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Electrical and Electronics Engineering publications abstract of: 04-2010 sorted by title, page: 0
» θ-QAM: A parametric quadrature amplitude modulation family and its performance in AWGN and fading channels
Abstract:
We study a parametric quadrature amplitude modulation (QAM) family, called θ-QAM, which includes other known constellations, such as square QAM (SQAM) and triangular QAM (TQAM), as special cases. The versatile structure of the θ-QAM signal constellation, which occurs from the varying angle between the signal points, results in achieving the minimum symbol error rate (SER) or bit error rate (BER), under an average power constraint. The theoretical study aims at providing insight into the trade-off between error performance and complexity of this parametric modulation scheme. Exact analytical expressions are obtained for the SER in additive white Gaussian Noise (AWGN) and Nakagami-m fading channels, while highly accurate BER approximations are presented. Finally, we find the optimum angles, in a minimal SER or BER sense, for a specific signal-to-noise ratio (SNR) and modulation order, M. This serves as an indicator for the appropriate constellation with respect to channel conditions and SER or BER requirements. The presented theoretical analysis is validated via extensive computer simulations.
Autors: Pappi, K.N.;Lioumpas, A.S.;Karagiannidis, G.K.;
Appeared in: IEEE Transactions on Communications
Publication date: Apr 2010, volume: 58, issue:4, pages: 1014 - 1019
Publisher: IEEE
 
» κ-Penalty: a novel approach to find κ-Disjoint paths with differentiated path costs
Abstract:
In this paper we investigate the issue of preplanned end-to-end protection against multiple failures. In recent communications networks, such protection is provided by finding a set of κ-disjoint paths for each demand. In particular, we analyze here the problem of calculating the set of κ-disjoint paths of a demand in multi-cost networks, where each network arc ah may be assigned κ different costs /spl epsilon/(1) h , /spl epsilon/(2) h , . . . , /spl epsilon/(κ) h . A novel algorithm, called κ-Penalty, is next introduced, in which the relation between values /spl epsilon/(i) h for each arc ah may be arbitrary.
Autors: Rak, J.;
Appeared in: IEEE Communications Letters
Publication date: Apr 2010, volume: 14, issue:4, pages: 354 - 356
Publisher: IEEE
 
» ’Power law scaling during physical vapor deposition under extreme shadowing conditions
Abstract:
A qualitative model that relates the period of the surface roughness to the vertical and spherical growth rates of glancing angle deposited (GLAD) nanorods suggests that rod self-shadowing is responsible for the previously reported temperature dependence in the rod width. Atomic shadowing interactions between neighboring rods as well as surface islands on the rod growth fronts control the morphological evolution which is quantified by the growth exponent p that relates the rod width w (=Ahp) to their height h. An analytical formalism predicts linear dependences of p and A on the average island separation and provides an explanation for reported anomalous p values. Experimental validation using new and previously published GLAD data for Al, Cr, Nb, and Ta shows quantitative agreement for all metallic systems under consideration and confirms the predicted dependences. In addition, a discontinuity in the p versus homologous deposition temperature θ suggests a critical value θc=0.24±0.02 for a transition from two-dimensional to three-dimensional island growth, which is independently confirmed by a discontinuity in the measured island width.
Autors: Mukherjee, S.;Gall, D.;
Appeared in: Journal of Applied Physics
Publication date: Apr 2010, volume: 107, issue:8, pages: 084301 - 084301-7
Publisher: IEEE
 
» “Non-Hydrogen-Transport” Characteristics of Dynamic Negative-Bias Temperature Instability
Abstract:
It has been proposed that negative-bias temperature instability (NBTI) is driven by interface-state generation, rate limited by hydrogen transport. In this letter, we examine dynamic NBTI characteristics and present evidence which does not conform to a hydrogen-transport model. It is observed that the amount of recovery of the threshold voltage shift remains constant, independent of the number of stress/recovery (SR) cycles. This behavior is inconsistent with the hydrogen-transport model, which stipulates that the amount of recovery should decrease with increase in the number of SR cycles. Results show that dynamic NBTI is made up of a symmetric “switching holetrap” mechanism superimposed on a background of relatively permanent deep-level hole trap and interface-state generation.
Autors: Teo, Z. Q.;Ang, D. S.;Ng, C. M.;
Appeared in: IEEE Electron Device Letters
Publication date: Apr 2010, volume: 31, issue:4, pages: 269 - 271
Publisher: IEEE
 
» “Rainbow” trapped in a self-similar coaxial optical waveguide
Abstract:
We report in this paper that the light waves with different frequencies can be selectively guided and spatially separated in a self-similar dielectric waveguide, where a hollow core is surrounded by a coaxial Thue–Morse multilayer. Due to the self-similar furcation feature in the photonic band structure, the transmission multibands are achieved. More interestingly, this dielectric waveguide supports “cladding modes,” which are spatially separated and confined along the waveguide. Consequently, a “rainbow” can be trapped (spatial confined but not stopped) in the Thue–Morse waveguide. The finding can be applied to designing miniaturized compact photonic devices, such as spectroscopy on a chip.
Autors: Hu, Qing;Zhao, Jin-Zhu;Peng, Ru-Wen;Gao, Feng;Zhang, Rui-Li;Wang, Mu;
Appeared in: Applied Physics Letters
Publication date: Apr 2010, volume: 96, issue:16, pages: 161101 - 161101-3
Publisher: IEEE
 
» 'Tis the gift to be simple
Abstract:
IC engineers rarely get to crash test their designs. Instead, they take pride in getting the design right the first time—no room for iterations and redesign. This is done by performing extensive computer simulations of designs. These simulations let engineers accurately predict the behavior of the design while it is still represented by computer data, before it ever becomes a real physical object.
Autors: Nassif, Sani R.;
Appeared in: IEEE Design & Test of Computers
Publication date: Apr 2010, volume: 27, issue:2, pages: 84 - 86
Publisher: IEEE
 
» (Fe,Si,Al)-based nanocrystalline soft magnetic alloys for cryogenic applications
Abstract:
In this work Al and Si are substituted for Fe in a (Fe,Si,Al)–Nb–B–Cu alloy with the goal of improving its magnetic properties at 77 K. The x-ray diffraction patterns for a series of five alloys annealed at 823 K shows a Fe3(Si,Al) ordered phase with some residual amorphous phase. The lowest coercivity at room temperature was observed for the alloy with composition Fe68Si15.5Al3.5Nb3B9Cu1. At cryogenic temperatures, the saturation magnetization of 99.3 Am2/kg, coercivity of 0.45 A/m, and resistivity of 122 μΩ cm for the Fe63Si17.5Al6Nb3B9Cu1 alloy, compare favorably to commercial alloys at 77 K.
Autors: Daniil, Maria;Osofsky, Michael S.;Gubser, Donald U.;Willard, Matthew A.;
Appeared in: Applied Physics Letters
Publication date: Apr 2010, volume: 96, issue:16, pages: 162504 - 162504-3
Publisher: IEEE
 
» 1.75-Kilowatt continuous-wave output fiber laser using homemade ytterbium-doped large-core fiber
Abstract:
We have demonstrated a homemade high-efficient ytterbium-doped fiber laser with up to 1.75 kW of continuous-wave output power at 1.09 [mu]m with a slope efficiency of 76%. The fiber is pumped by two laser diode array (LDA) sources launched through opposite ends. No undesirable effect is observed with increasing pump power, which suggests that the homemade fiber laser could produce higher power output by using more pump sources. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1668-1671, 2010; DOI 10.1002/mop.25226
Autors: Bing He, Jun Zhou, Qihong Lou, Yuhao Xue, Zhen Li, Wei Wang, Jingxing Dong, Yunrong Wei, Weibiao Chen
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» 10 Quick, Dirty, and Cheap Things to Improve Enterprise Security
Abstract:
These tips can help you cheaply build some security into your enterprise.
Autors: McGovern, James;Peterson, Gunnar;
Appeared in: IEEE Security & Privacy
Publication date: Apr 2010, volume: 8, issue:2, pages: 83 - 85
Publisher: IEEE
 
» 100-nm-Gate (Al,In)N/GaN HEMTs Grown on SiC With
Abstract:
One-hundred-nanometer-gate (Al,In)N/GaN high-electron-mobility transistors (HEMTs) grown on semi-insulating SiC achieve a maximum current density of 1.84 A/mm at , an extrinsic transconductance of 480 mS/mm, and a peak current gain cutoff frequency as high as , which is the highest so far reported for any (Al,In)N/GaN-based HEMT. This matches the best published values that we could find for 100-nm-gate (Al,Ga)N/GaN HEMTs, thus closing the cutoff frequency gap between (Al,In)N/GaN and (Al,Ga)N/GaN HEMTs. Additionally, similar devices grown on (111) high-resistivity silicon show a peak of 113 GHz, also setting a new performance benchmark for (Al,In)N/GaN HEMTs on silicon. Our findings indicate significant performance advantages for (Al,In)N/GaN HEMTs fabricated on SiC substrates. The improved performance for devices grown on SiC is derived from the superior transport properties of (Al,In)N/GaN 2DEGs grown on that substrate.
Autors: Sun, H.;Alt, A. R.;Benedickter, H.;Feltin, E.;Carlin, J.-F.;Gonschorek, M.;Grandjean, N.;Bolognesi, C. R.;
Appeared in: IEEE Electron Device Letters
Publication date: Apr 2010, volume: 31, issue:4, pages: 293 - 295
Publisher: IEEE
 
» 107-GHz (Al,Ga)N/GaN HEMTs on Silicon With Improved Maximum Oscillation Frequencies
Abstract:
We report high-speed fully passivated deep submicrometer (Al,Ga)N/GaN high-electron mobility transistors (HEMTs) grown on (111) high-resistivity silicon with current gain cutoff frequencies of as high as and maximum oscillation frequencies reaching . Together, these are the highest and values achieved for GaN-based HEMTs implemented on silicon substrates to date. The performance reported here is competitive with recently published results for similar geometry high-performance passivated HEMTs on semi-insulating silicon-carbide substrates.
Autors: Tirelli, S.;Marti, D.;Sun, H.;Alt, A. R.;Benedickter, H.;Piner, E. L.;Bolognesi, C. R.;
Appeared in: IEEE Electron Device Letters
Publication date: Apr 2010, volume: 31, issue:4, pages: 296 - 298
Publisher: IEEE
 
» 11W broad area 976 nm DFB lasers with 58% power conversion efficiency
Abstract:
A report is presented on how distributed feedback (DFB) lasers can achieve high optical power and power conversion efficiency together with a narrow vertical emission angle. Recently developed 976 nm DFB lasers emit 11 W, have a maximum power conversion efficiency of 58%, a spectral linewidth of ~0.4 nm FWHM and a narrow vertical far field of 28° FWHM. This considerable enhancement was obtained with an improved epitaxy design and optimised grating fabrication process. These are DFB lasers that achieve power, efficiency and emission angle values comparable to conventional Fabry-Perot lasers, but with spectral stabilisation. Accordingly, these lasers are particularly well suited for pumping fibre and solid-state lasers.
Autors: Schultz, C.M.;Crump, P.;Wenzel, H.;Brox, O.;Maabdorf, A.;Erbert, G.;Trankle, G.;
Appeared in: Electronics Letters
Publication date: Apr 2010, volume: 46, issue:8, pages: 580 - 581
Publisher: IEEE
 
» 187 MHz Subthreshold-Supply Charge-Recovery FIR
Abstract:
This paper presents a finite impulse response (FIR) filter chip that relies on a charge-recovery logic family to achieve multi-MHz clock frequencies with subthreshold DC supply levels. Fabricated in a 0.13 CMOS process with , the FIR operates with a two-phase power-clock in the 5 MHz–187 MHz range and with DC supplies in the 0.16 V–0.36 V range. Using a single DC supply, the chip achieves its most energy-efficient operating point when resonating at 20 MHz with a 0.27 V supply. Recovering 89% of the energy supplied to its 57 pF per-phase load, it consumes 15.57 pJ per cycle and yields 17.37 nW/Tap/MHz/InBit/CoeffBit. Using two subthreshold DC supplies at 20 MHz, energy per cycle can be further reduced by 17.1%, yielding 14.40 nW/Tap/MHz/InBit/CoeffBit.
Autors: Ma, W.-H.;Kao, J. C.;Sathe, V. S.;Papaefthymiou, M. C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 793 - 803
Publisher: IEEE
 
» 2-D finite difference time domain model of ultrasound reflection from normal and osteoarthritic human articular cartilage surface
Abstract:
Quantitative high-frequency ultrasonic evaluation of articular cartilage has shown a potential for the diagnosis of osteoarthritis, where the roughness of the surface, collagen and proteoglycan contents, and the density and mechanical properties of cartilage change concurrently. Experimentally, these factors are difficult to investigate individually and thus a numerical model is needed. The present study is the first one to use finite difference time domain modeling of pulse-echo measurements of articular cartilage. Ultrasound reflection from the surface was investigated with varying surface roughness, material parameters (Young's modulus, density, longitudinal, and transversal velocities) and inclination of the samples. The 2-D simulation results were compared with the results from experimental measurements of the same samples in an identical geometry. Both the roughness and the material parameters contributed significantly to the ultrasound reflection. The angular dependence of the ultrasound reflection was strong for a smooth cartilage surface but disappeared for the samples with a rougher surface. These results support the findings of previous experimental studies and indicate that ultrasound detects changes in the cartilage that are characteristic of osteoarthritis. In the present study there are differences between the results of the simulations and the experimental measurements. However, the systematic patterns in the experimental behavior are correctly reproduced by the model. In the future, our goal is to develop more realistic acoustic models incorporating inhomogeneity and anisotropy of the cartilage.
Autors: Kaleva, E.;Liukkonen, J.;Toyras, J.;Saarakkala, S.;Kiviranta, P.;Jurvelin, J.S.;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Apr 2010, volume: 57, issue:4, pages: 892 - 899
Publisher: IEEE
 
» 2-D Ultrasound Probe Complete Guidance by Visual Servoing Using Image Moments
Abstract:
This paper presents a visual-servoing method that is based on 2-D ultrasound (US) images. The main goal is to guide a robot actuating a 2-D US probe in order to reach a desired cross-section image of an object of interest. The method we propose allows the control of both in-plane and out-of-plane probe motions. Its feedback visual features are combinations of moments extracted from the observed image. The exact analytical form of the interaction matrix that relates the image-moments time variation to the probe velocity is developed, and six independent visual features are proposed to control the six degrees of freedom of the robot. In order to endow the system with the capability of automatically interacting with objects of unknown shape, a model-free visual servoing is developed. For that, we propose an efficient online estimation method to identify the parameters involved in the interaction matrix. Results obtained in both simulations and experiments validate the methods presented in this paper and show their robustness to different errors and perturbations, especially those inherent to the noisy US images.
Autors: Mebarki, R.;Krupa, A.;Chaumette, F.;
Appeared in: IEEE Transactions on Robotics
Publication date: Apr 2010, volume: 26, issue:2, pages: 296 - 306
Publisher: IEEE
 
» 2010 MTT-S-Sponsored IEEE Fellows [MTT-S Society News]
Abstract:
Lists the Microwave Theory and Techniques Society members that were elevated to the level of IEEE Fellow.
Autors: Trew, R.;
Appeared in: IEEE Microwave Magazine
Publication date: Apr 2010, volume: 11, issue:2, pages: 41 - 41
Publisher: IEEE
 
» 2D operators on topographic and non-topographic architectures - implementation, efficiency analysis, and architecture selection methodology
Abstract:
Topographic and non-topographic image processing architectures and chips, developed within the CNN community recently, are analyzed and compared. It is achieved on a way that the 2D operators are collected to classes according to their implementation methods on the different architectures, and the main implementation parameters of the different operator classes are compared. Based on the results, an efficient architecture selection methodology is formalized. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: Ákos Zarándy, Csaba Rekeczky
Appeared in: International Journal of Circuit Theory and Applications
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» 3-D phantom and in vivo cardiac speckle tracking using a matrix array and raw echo data
Abstract:
Cardiac motion has been tracked using various methods, which vary in their invasiveness and dimensionality. One such noninvasive modality for cardiac motion tracking is ultrasound. Three-dimensional ultrasound motion tracking has been demonstrated using detected data at low volume rates. However, the effects of volume rate, kernel size, and data type (raw and detected) have not been sufficiently explored. First comparisons are made within the stated variables for 3-D speckle tracking. Volumetric data were obtained in a raw, baseband format using a matrix array attached to a high parallel receive beam count scanner. The scanner was used to acquire phantom and human in vivo cardiac volumetric data at 1000-Hz volume rates. Motion was tracked using phase-sensitive normalized cross-correlation. Subsample estimation in the lateral and elevational dimensions used the grid-slopes algorithm. The effects of frame rate, kernel size, and data type on 3-D tracking are shown. In general, the results show improvement of motion estimates at volume rates up to 200 Hz, above which they become stable. However, peak and pixel hopping continue to decrease at volume rates higher than 200 Hz. The tracking method and data show, qualitatively, good temporal and spatial stability (for independent kernels) at high volume rates.
Autors: Byram, B.C.;Holley, G.;Giannantonio, D.M.;Trahey, G.E.;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Apr 2010, volume: 57, issue:4, pages: 839 - 854
Publisher: IEEE
 
» 3-D System Integration of Processor and Multi-Stacked SRAMs Using Inductive-Coupling Link
Abstract:
This paper describes a three-dimensional (3-D) system integration of a full-fledged processor chip and two memory chips using inductive coupling. To attain a 3-D communication link with a smaller area and lower power-consumption, shortening the link distance and preventing signal degradation due to unused inductors are important challenges. Therefore, we developed a new 3D-integrated wire-penetrated multi-layer structure for a shorter link distance and an open-skipped-inductor scheme for suppressing signal degradation. In addition, to avoid undefined-value propagation in stacking multi-memories using an inductive-coupling link, we proposed a memory-access-control scheme with a pinpoint-data-capture scheme. We demonstrate that three fabricated chips can be successfully AC-coupled using inductive coupling. The power and area efficiency of the link are 1 pJ/b and , respectively, which are the same as those of two-chip integration.
Autors: Saen, M.;Osada, K.;Okuma, Y.;Niitsu, K.;Shimazaki, Y.;Sugimori, Y.;Kohama, Y.;Kasuga, K.;Nonomura, I.;Irie, N.;Hattori, T.;Hasegawa, A.;Kuroda, T.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 856 - 862
Publisher: IEEE
 
» 3D Isotropic Dispersion (ID)-FDTD Algorithm: Update Equation and Characteristics Analysis
Abstract:
Three 3D isotropic dispersion-finite-difference time-domain (ID-FDTD) algorithms are formulated based on two new spatial difference equations. The difference equations approximate the spatial derivatives in Maxwell's equation using more spatial sampling points distributed in an isotropic manner. The final spatial difference equation is a weighted summation of the two new difference and the conventional central difference equations. Therefore, based on the proposed spatial difference equation and choices of the weighting factors, seven different FDTD schemes can be formulated, which include the Yee scheme. Among the seven schemes, three methods can show isotropy of the dispersion superior to that of the Yee scheme. The weighting factors for the three schemes are numerically determined to minimize the anisotropy of the dispersion by using an optimization technique. In this paper, the dispersion & stability characteristics and the numerical complexity of the three ID-FDTD schemes are addressed. Also, the upper bound of the Courant number of the three ID-FDTD schemes is heuristically proposed and numerically verified. One scattering problem is considered to show the improved accuracy of the proposed ID-FDTD scheme.
Autors: Kim, W.-T.;Koh, I.-S.;Yook, J.-G.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Apr 2010, volume: 58, issue:4, pages: 1251 - 1259
Publisher: IEEE
 
» 4,4',4''-Tris(4-naphthalen-1-yl-phenyl)amine as a multifunctional material for organic light-emitting diodes, organic solar cells, and organic thin-film transistors
Abstract:
We have developed the first multifunctional organic material, 4,4',4''-tris(4-naphthalen-1-yl-phenyl)amine (1-TNPA), which can be used as a deep blue emitting and hole-transporting material in organic light-emitting diodes (OLEDs), as a donor material in organic solar cells (OSCs), and as an active material in organic thin-film transistors (OTFTs). In particular, in the case of 1-TNPA-based OLEDs, efficient emission characteristics, the emission of deep-blue light similar to the NTSC standard blue, and more efficient hole transport than that in the case of NPD-based OLEDs were observed. 1-TNPA can be also used as a donor in OSCs and as an organic semiconductor in OTFTs.
Autors: Jongchul, Kwon , Myoung Ki, Kim , Jung-Pyo, Hong , Woochul, Lee , Seunguk, Noh , ...
Appeared in: Organic Electronics
Publication date: Apr 2010
Publisher: Elsevier B.V.
 
» 4-D SAR Imaging: The Case Study of Rome
Abstract:
Four-dimensional synthetic aperture radar (SAR) imaging, also known as differential SAR tomography, is a new research topic in the framework of coherent multitemporal/multibaseline SAR processing that extends the interferometry concept. Four-dimensional SAR imaging-based processing could improve the capability of ground-scatterer monitoring with respect to classical differential interferometric SAR processing. The first results on the applicability of such an advanced tomographic SAR processing to real spaceborne data were recently discussed in the literature. In this letter, we present the results of an experiment with a data set that demonstrates the potentialities of this new technique for monitoring complex targets, such as infrastructures.
Autors: Fornaro, G.;Serafino, F.;Reale, D.;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Apr 2010, volume: 7, issue:2, pages: 236 - 240
Publisher: IEEE
 
» 6.7 GHz high-Q active inductor design using parasitic cancellation with process variation control
Abstract:
A correction to a previously published Q- and bandwidth-enhancing design technique using parasitic cancellation to obtain a high-Q active inductor operating at frequencies above 6 GHz using nonminimal- length CMOS technologies is presented. A measured inductance of 1.9 nH is acheived at 6.75 GHz with a Q of 38 occupying only 0.0026 mm2 silicon chip area. The active inductor is then used to obtain a narrowband output matching element for an LNA with its input unmatched in 130 nm CMOS technology. The input-unmatched inductorless LNA parameters measured at 6.7 GHz are: S21 12.8 dB, 3.5 GHz BW, NF 7.2 dB (with simulated NFmin of 3.3 dB) and S22 less than 220 dB, while consuming only 6.4 mW with a 1.2 V supply. The high NF can be easily reduced to NFmin with input matching.
Autors: Ahmed, A.;Wight, J.;
Appeared in: Electronics Letters
Publication date: Apr 2010, volume: 46, issue:7, pages: 486 - 487
Publisher: IEEE
 
» 60¿110 GHz low loss HDI transitions for LCP-packaged silicon substrate
Abstract:
Wideband 3D transitions from 60 to 110 GHz using 50 μm via technology on liquid crystal polymer (LCP) are presented. A conductor backed coplanar waveguide (CBCPW) transition on a homogeneous LCP sample shows less than 0.8 dB loss from 60 to 110 GHz. In addition, a CBCPW-to-CBCPW and a CBCPW-to-CPW transition on LCP bonded to silicon substrate are presented also in the range 60¿110 GHz. The CBCPW-to-CBCPW transition shows less than 0.5 dB loss up to 100 GHz. The CBCPW-to-CPW transition yields less than 1 dB loss up to 110 GHz. These transitions are the first characterisation of vias in organic substrate packaged silicon in the 60¿110 GHz frequency range.
Autors: Chung, D.J.;Papapolymerou, J.;
Appeared in: Electronics Letters
Publication date: Apr 2010, volume: 46, issue:8, pages: 577 - 578
Publisher: IEEE
 
» 664 GHz dual polarisation frequency selective surface
Abstract:
The design, manufacture and performance of a frequency selective surface (FSS) which is required to operate simultaneously in the TE and TM planes at 45° incidence over the frequency range 173¿ 671 GHz is presented. The FSS was designed to allow transmission of radiation over a 2% bandwidth centred at 664 GHz and reflect four channels centred at 448, 325, 243 and 183 GHz with a loss < 0.5 dB. The filter was formed from silicon on insulator material which was precision micromachined with an array of Jerusalem cross-slots and encapsulated with high conductivity silver. Experimental results yielded virtually identical spectral responses in the two polarisation planes with the electromagnetic performance exceeding the above specifications.
Autors: Dickie, R.;Cahill, R.;Mitchell, N.;Gamble, H.;Fusco, V.;Munro, Y.;Rea, S.;
Appeared in: Electronics Letters
Publication date: Apr 2010, volume: 46, issue:7, pages: 472 - 474
Publisher: IEEE
 
» BaTiO3 ferroelectric nanoparticles dispersed in 5CB nematic liquid crystal: Synthesis and electro-optical characterization
Abstract:
We report in this paper studies on a mixture of nematic liquid crystal (5CB) and BaTiO3 ferroelectric nanoparticles (NPs). Apart a drastic change in the electro-optical (EO) properties of this mixture, which is reported as a conclusion, we focused our attention onto the characteristics of those NPs. The initial powder obtained by solid way is first analyzed: this material is crystallized in the ferroelectric phase as shown by x-ray diffraction and Raman spectroscopy. A high speed second milling was performed to obtain NPs: they have been characterized by high resolution transmission electron microscopy (size and structural characterizations) and by dynamic light scattering. Then these NPs were blended with a nematic liquid crystal (5CB). Raman spectroscopy measurements were used to measure and compare the scalar order parameter of both samples. The EO properties were measured in planar liquid crystal cell configuration by using classical EO setup. We amazingly found a significant decrease in the Freedericksz threshold, compared to the pure material. This is to be compared to the Glushchenko’s measurement, who observed no variation, for a similar mixture in concentration, but for smaller NPs. Switching times were measured using the same setup and we noticed a decrease in the “τon” for the 5CB+BTO mixture compared to the pure 5CB one.
Autors: Blach, J.-F.;Saitzek, S.;Legrand, C.;Dupont, L.;Henninot, J.-F.;Warenghem, M.;
Appeared in: Journal of Applied Physics
Publication date: Apr 2010, volume: 107, issue:7, pages: 074102 - 074102-7
Publisher: IEEE
 
» m-plane (101_0) InN heteroepitaxied on (100)-γ-LiAlO2 substrate: Growth orientation control and characterization of structural and optical anisotropy
Abstract:
Heteroepitaxial growth of m-plane (101_0) InN film on (100)-γ-LiAlO2 (LAO) substrate has been realized by plasma-assisted molecular-beam epitaxy. Surface treatment of LAO substrate plays an important role in controlling the resultant phase and purity of m-plane InN. X-ray diffraction, reflection high-energy electron diffraction, electron back scatter diffraction, and transmission electron microscopy (TEM) studies revealed formation of pure m-plane InN film using substrate preannealed at 800 °C but without any nitridation. In contrast, using substrate with nitridation but otherwise identical pretreatment and growth conditions, c-plane (0001) InN columnar structure was grown, instead of m-plane InN film. Structural anisotropy of the m-plane InN epitaxied on LAO is attributed to the I1 type base-plane stacking faults according to the modified Williamson–Hall and TEM analyses. A rectangular-to-rectangular atomic stacking sequence and a commensurately lattice-matched condition in epitaxial direction of [12_10]InN||[001]LAO with a small misfit strain of ∼0.2% are proposed to realize this heteroepitaxy. Angle-dependent polarized UV-Raman spectra showed that all the InN phonon modes follow Raman selection rule well. Strong polarization anisotropy of photoluminescence (PL) emission located at ∼0.63 eV was observed, as evidenced by a high polarization degree of 87% of the m-plane InN determined by infrared polarized PL spectroscopy.
Autors: Hsiao, Ching-Lien;Chen, Jr-Tai;Hsu, Hsu-Cheng;Liao, Ying-Chieh;Tseng, Po-Han;Chen, Yen-Ting;Feng, Zhe Chuan;Tu, Li-Wei;Chou, Mitch M. C.;Chen, Li-Chyong;Chen, Kuei-Hsien;
Appeared in: Journal of Applied Physics
Publication date: Apr 2010, volume: 107, issue:7, pages: 073502 - 073502-7
Publisher: IEEE
 
» -Optimization in Block-Sparse Compressed Sensing and Its Strong Thresholds
Abstract:
It has been known for a while that -norm relaxation can in certain cases solve an under-determined system of linear equations. Recently, E. Candes (“Robust uncertainty principles: Exact signal reconstruction from highly incomplete frequency information,” IEEE Trans. Information Theory, vol. 52, no. 12, pp. 489–509, Dec. 2006) and D. Donoho (“High-dimensional centrally symmetric polytopes with neighborlines proportional to dimension,” Disc. Comput. Geometry, vol. 35, no. 4, pp. 617–652, 2006) proved (in a large dimensional and statistical context) that if the number of equations (measurements in the compressed sensing terminology) in the system is proportional to the length of the unknown vector then there is a sparsity (number of nonzero elements of the unknown vector) also proportional to the length of the unknown vector such that -norm relaxation succeeds in solving the system. In this paper, in a large dimensional and statistical context, we determine sharp lower bounds on the values of allowable sparsity for any given number (proportional to the length of the unknown vector) of equations for the case of the so-called block-sparse unknown vectors considered in “On the reconstruction of block-sparse signals with an optimal number of measurements,” (M. Stojnic , IEEE Trans, Signal Processing, submitted for publication.
Autors: Stojnic, M.;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Apr 2010, volume: 4, issue:2, pages: 350 - 357
Publisher: IEEE
 
» Determination Method With the Help of the Virgin Magnetization Curve of a Superconducting Cylinder
Abstract:
It is well known that the critical current density of a superconducting material depends on the magnetic flux density . For practical applications, it is essential to have accurate information about , which can be obtained from different experimental techniques (transport current, hysteretic cycle, and ac susceptibility). This paper presents a simple and quick experimental determination method for a superconducting cylinder. A first experimental evaluation method consists of measuring the magnetization cycle and determining the width of this cycle for each value of . This is generally done using the Bean model, where is considered constant. A more accurate method is presented in this paper. The cylinder first magnetization curve is calculated with the Kim model [ ] and with a linear model and compared with the measured first magnetization curve . In so doing, and are determined, and the results obtained using both $J_{C}(B)$ determination methods are compared and discussed.
Autors: Douine, B.;Leveque, J.;Mezani, S.;
Appeared in: IEEE Transactions on Applied Superconductivity
Publication date: Apr 2010, volume: 20, issue:2, pages: 82 - 86
Publisher: IEEE
 
» -Switched Performance of Diode Pumped Nd : Lu Y VO Lasers
Abstract:
A continuous-wave (CW) and actively -switched Nd :  laser was demonstrated for the first time. The maximum CW output power of 9.92 W was obtained, corresponding to an optical conversion efficiency of 52.5% and a slope efficiency of 56.1%. For actively -switched operation, a 10.4-ns pulse was attained with the repetition frequency of 10 kHz. Under the same conditions, the pulse energy and the peak power were estimated to be 0.6 mJ and 57.9 kW, respectively.
Autors: Zhang, S.;Xu, L.;Wang, Y.;Wang, M.;Peng, H.;Xu, J.;Zhao, B.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Apr 2010, volume: 22, issue:8, pages: 556 - 558
Publisher: IEEE
 
» -Band Bandpass Filter Using Micromachined Air-Cavity Resonator With Current Probes
Abstract:
This letter presents a -band micromachined air-cavity bandpass filter (BPF) using a novel integration method of a micromachined silicon air-cavity resonator with silicon pillars. With silicon pillars, which were fabricated simultaneously with a deep reactive ion etching process for forming a cavity structure, a micromachined silicon air-cavity can be easily integrated on a package substrate with a flip-chip interconnection. In this work, a thin-film substrate with a flip-chip interconnection was employed as a package substrate, in which the silicon pillars were used as the current probe between the air-cavity resonator and TFMS input/output feeding lines. With the novel integration of the air-cavity resonator, a -band four-pole BPF has been successfully demonstrated on a thin-film substrate with a flip-chip interconnection, which exhibits a minimum insertion loss of 1.3 dB and return loss better than 16 dB with a 4.9% 3-dB fractional bandwidth at a center frequency of 93.7 GHz.
Autors: Song, S.;Yoo, C.-S;Seo, K.-S.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Apr 2010, volume: 20, issue:4, pages: 205 - 207
Publisher: IEEE
 
» Controller Design for Networked Predictive Control Systems Based on the Average Dwell-Time Approach
Abstract:
This brief focuses on the problem of control for a class of networked control systems with time-varying delay in both forward and backward channels. Based on the average dwell-time method, a novel delay-compensation strategy is proposed by appropriately assigning the subsystem or designing the switching signals. Combined with this strategy, an improved predictive controller design approach in which the controller gain varies with the delay is presented to guarantee that the closed-loop system is exponentially stable with an -norm bound for a class of switching signal in terms of nonlinear matrix inequalities. Furthermore, an iterative algorithm is presented to solve these nonlinear matrix inequalities to obtain a suboptimal minimum disturbance attenuation level. A numerical example illustrates the effectiveness of the proposed method.
Autors: Wang, R.;Wang, B.;Liu, G.-P.;Wang, W.;Rees, D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Apr 2010, volume: 57, issue:4, pages: 310 - 314
Publisher: IEEE
 
» -Based Memory Cell With a Self-Rectifying Effect for Crossbar WORM Memory Application
Abstract:
A memory cell based on n+-Si/ZrO2/Pt structure with self-rectifying properties is demonstrated for write-once-read-many-times (WORM) memory application. The fresh devices can be set to a low resistance state (LRS) as an antifuse and keep in LRS permanently with a rectification ratio exceeding 104. The memory devices show a large on/off ratio of about 106 and narrow resistance distributions before and after programming. The different transport mechanisms of forward and reverse currents are studied, which are responsible for this reliable self-rectifying characteristic. The demonstrated memory cell with self-rectifying properties has potential application in high-density passive crossbar WORM memory.
Autors: Qingyun Zuo;Shibing Long;Shiqian Yang;Qi Liu;Lubing Shao;Qin Wang;Sen Zhang;Yingtao Li;Yan Wang;Ming Liu;
Appeared in: IEEE Electron Device Letters
Publication date: Apr 2010, volume: 31, issue:4, pages: 344 - 346
Publisher: IEEE
 
» -Optimization in Block-Sparse Compressed Sensing and Its Strong Thresholds
Abstract:
It has been known for a while that ¿1-norm relaxation can in certain cases solve an under-determined system of linear equations. Recently, E. Candes (¿Robust uncertainty principles: Exact signal reconstruction from highly incomplete frequency information,¿ IEEE Trans. Information Theory, vol. 52, no. 12, pp. 489-509, Dec. 2006) and D. Donoho (¿High-dimensional centrally symmetric polytopes with neighborlines proportional to dimension,¿ Disc. Comput. Geometry, vol. 35, no. 4, pp. 617-652, 2006) proved (in a large dimensional and statistical context) that if the number of equations (measurements in the compressed sensing terminology) in the system is proportional to the length of the unknown vector then there is a sparsity (number of nonzero elements of the unknown vector) also proportional to the length of the unknown vector such that ¿1-norm relaxation succeeds in solving the system. In this paper, in a large dimensional and statistical context, we determine sharp lower bounds on the values of allowable sparsity for any given number (proportional to the length of the unknown vector) of equations for the case of the so-called block-sparse unknown vectors considered in ¿On the reconstruction of block-sparse signals with an optimal number of measurements,¿ (M. Stojnic et al., IEEE Trans, Signal Processing, submitted for publication.
Autors: Stojnic, M.;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Apr 2010, volume: 4, issue:2, pages: 350 - 357
Publisher: IEEE
 
» -Band Bandpass Filter Using Micromachined Air-Cavity Resonator With Current Probes
Abstract:
This letter presents a -band micromachined air-cavity bandpass filter (BPF) using a novel integration method of a micromachined silicon air-cavity resonator with silicon pillars. With silicon pillars, which were fabricated simultaneously with a deep reactive ion etching process for forming a cavity structure, a micromachined silicon air-cavity can be easily integrated on a package substrate with a flip-chip interconnection. In this work, a thin-film substrate with a flip-chip interconnection was employed as a package substrate, in which the silicon pillars were used as the current probe between the air-cavity resonator and TFMS input/output feeding lines. With the novel integration of the air-cavity resonator, a -band four-pole BPF has been successfully demonstrated on a thin-film substrate with a flip-chip interconnection, which exhibits a minimum insertion loss of 1.3 dB and return loss better than 16 dB with a 4.9% 3-dB fractional bandwidth at a center frequency of 93.7 GHz.
Autors: Song, S.;Yoo, C.-S;Seo, K.-S.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Apr 2010, volume: 20, issue:4, pages: 205 - 207
Publisher: IEEE
 
» A 0.13?m CMOS adaptive sigma-delta modulator for triple-mode GSM/Bluetooth/UMTS applications
Abstract:
This paper describes the design and experimental characterization of a 0.13?m CMOS switched-capacitor reconfigurable cascade ?? modulator intended for multi-standard GSM/Bluetooth/UMTS hand-held devices. Both architectural- and circuital-level reconfiguration strategies are incorporated in the chip in order to adapt the effective resolution and the output rate to different standard specifications with optimized power dissipation. This is achieved by properly combining different reconfiguration modes that include the variation in the order of the loop filter (3rd- or 4th-order), the clock frequency (40 or 80MHz), the internal quantization (1 or 2bits), and the bias currents of the amplifiers. The selection of the modulator...
Autors: Alonso, Morgado , Rocío, del Río , José M., de la Rosa , Rafael, Castro-López , Belén, Pérez-Verdú
Appeared in: Microelectronics Journal
Publication date: Apr 2010
Publisher: Elsevier B.V.
 
» A 0.2 mm , 27 Mbps 3 mW ADC/FFT-Less FDM BAN Receiver With Energy Exploitation Capability
Abstract:
A 27-Mbps, frequency-division multiplexing (FDM) receiver was developed. The 3-channel FDM signal is demodulated in the receiver with a traveling subband demodulator using intra-symbol intermittent demodulation for each subband, which does not require an analog-to-digital converter/fast Fourier transform. Also, the receiver sustains a sensitivity of dBm comparable to that of, e.g., Bluetooth standards ( dBm) with respect to 14-dB sensitivity degradation caused by signal bandwidth enhancement, with receiver power dissipation of 3 mW. Furthermore, we have successfully demonstrated energy-exploitation capability from the power of unused FDM signals and interference.
Autors: Ishizaki, H.;Mizuno, M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 921 - 927
Publisher: IEEE
 
» A 0.5 V Sub-Microwatt CMOS Image Sensor With Pulse-Width Modulation Read-Out
Abstract:
Energy minimization is a critical goal in size-constrained wireless sensors. Sensing elements are traditionally power hungry and require special attention in low energy systems. In this work, we study ultra-low power image sensors. In particular, we explore the use of aggressive voltage scaling in CMOS image sensors for applications ranging from retinal prostheses to battlefield monitoring and surveillance. We begin with a discussion of the challenges faced by a traditional 3T active pixel sensor as the supply voltage scales to 0.5 V and below. We then discuss an image sensor with pulse-width modulation read-out that is optimized for 0.5 V operation. A 0.13 test-chip with a 128 128 pixel array is shown to be functional with as low as 0.45 V with energy consumption of 140 nJ/frame at (8.5 frames per second) and power consumption of only 700 nW at (0.5 frames per second). A focus is also placed on quantifying the noise implications of low voltage operation on the test-chip, which has a measured signal-to-noise ratio of 23.4 dB in saturation at .
Autors: Hanson, S.;Foo, Z.;Blaauw, D.;Sylvester, D.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 759 - 767
Publisher: IEEE
 
» A 0.6 mW/Gb/s, 6.4–7.2 Gb/s Serial Link Receiver Using Local Injection-Locked Ring Oscillators in 90 nm CMOS
Abstract:
This paper describes a quad-lane, 6.4–7.2 Gb/s serial link receiver prototype using a forwarded clock architecture. A novel phase deskew scheme using injection-locked ring oscillators (ILRO) is proposed that achieves greater than one UI of phase shift for multiple clock phases, eliminating phase rotation and interpolation required in conventional architectures. Each receiver, optimized for power efficiency, consists of a low-power linear equalizer, four offset-cancelled quantizers for 1:4 demultiplexing, and an injection-locked ring oscillator coupled to a low-voltage swing, global clock distribution. Measurement results show a 6.4–7.2 Gb/s data rate with across 14 cm of PCB, and also an 8.0 Gb/s data rate through 4 cm of PCB. Designed in a 1.2 V, 90 nm CMOS process, the ILRO achieves a wide tuning range from 1.6–2.6 GHz. The total area of each receiver is 0.0174 , resulting in a measured power efficiency of 0.6 mW/Gb/s.
Autors: Hu, K.;Jiang, T.;Wang, J.;O'Mahony, F.;Chiang, P. Y.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 899 - 908
Publisher: IEEE
 
» A 10-bit 50-MS/s SAR ADC With a Monotonic Capacitor Switching Procedure
Abstract:
This paper presents a low-power 10-bit 50-MS/s successive approximation register (SAR) analog-to-digital converter (ADC) that uses a monotonic capacitor switching procedure. Compared to converters that use the conventional procedure, the average switching energy and total capacitance are reduced by about 81% and 50%, respectively. In the switching procedure, the input common-mode voltage gradually converges to ground. An improved comparator diminishes the signal-dependent offset caused by the input common-mode voltage variation. The prototype was fabricated using 0.13- 1P8M CMOS technology. At a 1.2-V supply and 50 MS/s, the ADC achieves an SNDR of 57.0 dB and consumes 0.826 mW, resulting in a figure of merit (FOM) of 29 fJ/conversion-step. The ADC core occupies an active area of only .
Autors: Liu, C.-C.;Chang, S.-J.;Huang, G.-Y.;Lin, Y.-Z.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 731 - 740
Publisher: IEEE
 
» A 12-Bit Vernier Ring Time-to-Digital Converter in 0.13 CMOS Technology
Abstract:
A 12-bit Vernier ring time-to-digital converter (TDC) with time resolution of 8 ps for digital-phase-locked-loops (DPLL) is presented. This novel Vernier ring TDC places the Vernier delay cells and arbiters in a ring format and reuses them for the measurement of the input time interval. The proposed TDC thus achieves large detectable range, fine time resolution, small die size and low power consumption simultaneously. A pre-logic unit is developed to measure both positive and negative phase errors for DPLL applications. The TDC achieves a large detectable range of 12 bits with core area of in a 0.13 CMOS technology. The total power consumption for the entire TDC chip is only 7.5 mW with a 1.5 V power supply, while operating at a clock frequency of 15 MSPS.
Autors: Yu, J.;Dai, F. F.;Jaeger, R. C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 830 - 842
Publisher: IEEE
 
» A 20 mV Input Boost Converter With Efficient Digital Control for Thermoelectric Energy Harvesting
Abstract:
This paper presents a low power boost converter for thermoelectric energy harvesting that demonstrates an efficiency that is 15% higher than the state-of-the-art for voltage conversion ratios above 20. This is achieved by utilizing a technique allowing synchronous rectification in the discontinuous conduction mode. A low-power method for input voltage monitoring is presented. The low input voltage requirements allow operation from a thermoelectric generator powered by body heat. The converter, fabricated in a 0.13 CMOS process, operates from input voltages ranging from 20 mV to 250 mV while supplying a regulated 1 V output. The converter consumes 1.6 (1.1) of quiescent power, delivers up to 25 (175) of output power, and is 46 (75)% efficient for a 20 mV and 100 mV input, respectively.
Autors: Carlson, E. J.;Strunz, K.;Otis, B. P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 741 - 750
Publisher: IEEE
 
» A 21-Gb/s 87-mW Transceiver With FFE/DFE/Analog Equalizer in 65-nm CMOS Technology
Abstract:
A 21-Gb/s backplane transceiver has been presented. The transmitter incorporates half-rate topology with purely digital blocks to substantially reduce power consumption. The receiver employs analog and decision-feedback equalizers in a full-rate structure to avoid complicated structure. The one-tap decision-feedback equalizer merges the summer and the slicer into the flipflop, shortening the feedback path and speeding up the operation considerably. Fabricated in 65-nm CMOS, the transceiver (excluding clock generating PLL and CDR circuits) delivers 21-Gb/s data (2 1 PRBS) over 40-cm FR4 channel while consuming 87 mW from a 1.2-V supply.
Autors: Wang, H.;Lee, J.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 909 - 920
Publisher: IEEE
 
» A 3-D Hybrid Finite Element Model to Characterize the Electrical Behavior of Cutaneous Tissues
Abstract:
Finite element modeling of the skin is useful to study the electrical properties of cutaneous tissues and gain a better understanding of the current distribution within the skin. Such an epithelial finite element model comprises extremely thin structures like cellular membranes, nuclear membranes, and the extracellular fluid. Meshing such narrow spaces considerably increases the number of elements leading to longer computing time. This also greatly reduces the number of epithelial cells that can be assembled before reaching computing limitations. To avoid the problem of meshing extremely narrow spaces while unnecessarily increasing the number of elements, we present a new hybrid modeling approach to develop a 3-D finite element model of the skin. This skin model comprises all skin layers, different lesion types, and a complete electrode model. It is used to analyze the complex electrical behavior of normal and malignant skin tissues. The current distribution within this model is also simulated to assess the depth of field achievable by an electrical impedance tomography system at different operating frequencies.
Autors: Hartinger, A. E.;Guardo, R.;Kokta, V.;Gagnon, H.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Apr 2010, volume: 57, issue:4, pages: 780 - 789
Publisher: IEEE
 
» A 31 ns Random Cycle VCAT-Based 4F DRAM With Manufacturability and Enhanced Cell Efficiency
Abstract:
A functional DRAM was implemented based on the technology combination of stack capacitor and surrounding-gate vertical channel access transistor (VCAT). A high performance VCAT has been developed showing excellent Ion-Ioff characteristics with more than twice turn-on current compared with the conventional recessed channel access transistor (RCAT). A new design methodology has been applied to accommodate cell array, achieving both high performance and manufacturability. Especially, core block restructuring, word line (WL) strapping and hybrid bit line (BL) sense-amplifier (SA) scheme play an important role for enhancing AC performance and cell efficiency. A 50 Mb test chip was fabricated by 80 nm design rule and the measured random cycle time (tRC) and read latency (tRCD) are 31 ns and 8 ns, respectively. The median retention time for 88 Kb sample array is about 30 s at 90 C under dynamic operations. The core array size is reduced by 29% compared with conventional DRAM.
Autors: Song, K.-W.;Kim, J.-Y.;Yoon, J.-M.;Kim, S.;Kim, H.;Chung, H.-W.;Kim, K.;Park, H.-W.;Kang, H. C.;Tak, N.-K.;Park, D.;Kim, W.-S.;Lee, Y.-T.;Oh, Y. C.;Jin, G.-Y.;Yoo, J.;Oh, K.;Kim, C.;Jun, Y.-H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 880 - 888
Publisher: IEEE
 
» A 32-Mb SPRAM With 2T1R Memory Cell, Localized Bi-Directional Write Driver and `1'/`0' Dual-Array Equalized Reference Scheme
Abstract:
A 32-Mb SPin-transfer torque RAM (SPRAM) chip was demonstrated with an access time of 32 ns and a cell write-time of 40 ns at a supply voltage of 1.8 V. The chip was fabricated with 150-nm CMOS and a 100 200-nm tunnel magneto-resistive (TMR) device element. A required thermal stability of 67 of the TMR device was estimated by taking into account the disturbances during read operations and data retention periods of 10 years for nonvolatile operation. The 32-Mb SPRAM chip features three circuit technologies suitable for a large-scale array: 1) a two-transistor, one-resistor (2T1R) type memory cell for achieving a sufficiently large write current despite the small cell size, 2) a compact read/write separated hierarchy bit/source-line structure with a localized bi-directional write driver for efficiently distributing write current, and 3) a '1'/'0' dual-array equalized reference scheme for stable read operation.
Autors: Takemura, R.;Kawahara, T.;Miura, K.;Yamamoto, H.;Hayakawa, J.;Matsuzaki, N.;Ono, K.;Yamanouchi, M.;Ito, K.;Takahashi, H.;Ikeda, S.;Hasegawa, H.;Matsuoka, H.;Ohno, H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 869 - 879
Publisher: IEEE
 
» A 4 kb Metal-Fuse OTP-ROM Macro Featuring a 2 V Programmable 1.37 m 1T1R Bit Cell in 32 nm High-k Metal-Gate CMOS
Abstract:
A 4 kb high-density PROM array featuring the first high-volume manufacturable metal-fuse technology in 32 nm high-k metal-gate CMOS is introduced. In contrast to traditional salicided polysilicon based 2-D fuse cells, the metal-fuse technology enables a 3-D cell topology with program device and fuse element stacked on each other, achieving a 1.37 m cell footprint. The 128-row by 32-column array with an asymmetric tunable static sense scheme can operate down to 0.5 V and provides multi-bit programming capability. Programming success using a 2 V-1 s pulse condition is demonstrated. The technology is scalable and maintains full compatibility with modern high-k metal-gate processes.
Autors: Kulkarni, S. H.;Chen, Z.;He, J.;Jiang, L.;Pedersen, M. B.;Zhang, K.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 863 - 868
Publisher: IEEE
 
» A 4.3 GB/s Mobile Memory Interface With Power-Efficient Bandwidth Scaling
Abstract:
This paper presents a 4.3 GB/s mobile memory interface that utilizes low power states with rapid transition times to support power efficient signaling over a wide range of effective bandwidths. The fastest power state transition is implemented by a global synchronous clock pause that gates dynamic power consumption without any loss of system state. Extensive use of CMOS circuit topologies, with low static power consumption, provides maximum power savings when the clocks are paused. The memory controller forwards a half bit-rate clock to the memory for synchronous communication, which is similarly paused in the low power state. Thus, dynamic interface power on the memory itself naturally responds to the clock pausing, without any explicit communication from the controller or special low-power state on the memory. Low-swing differential signaling based on a push-pull voltage mode driver results in good signal integrity and power efficiency at peak activity. Test-chips fabricated in a 40 nm low-power CMOS technology achieve 3.3 mW/Gb/s power efficiency at 4.3 GB/s data bandwidth, and support better than 5 mW/Gb/s operation over a range from 0.03 to 4.3 GB/s.
Autors: Leibowitz, B.;Palmer, R.;Poulton, J.;Frans, Y.;Li, S.;Wilson, J.;Bucher, M.;Fuller, A. M.;Eyles, J.;Aleksic, M.;Greer, T.;Nguyen, N. M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 889 - 898
Publisher: IEEE
 
» A 54-GHz push-push VCO with wide tuning range in 0.18-[mu]m CMOS technology
Abstract:
The design of a V-band 54-GHz push-push voltage-controlled oscillator (VCO) with a wide tuning range is presented in this article. The circuit is fabricated using 0.18-[mu]m CMOS technology. A new single-turn inductor structure with a smaller inductance, which can reduce the substrate loss, is adopted for the oscillator core to have the performances of low phase noise and a wide tuning range. Besides, a new technique that delivers the output signal from the common drain of the two-stage buffers has been proposed to enhance the output power. The VCO core dissipates 8.54 mW from a 2 V supply. The buffer stage consumes 10.11 mW for raising the measured output power level up to -25 dBm. The measured output phase noise at an offset of 1 MHz from the carrier frequency of 53.0 GHz is about -94.45 dBc/Hz. This VCO, with a tuning range of 2.68 GHz (4.9%), shows the tuning-related figure-of-merit FOMT of -170.12 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1480-1483, 2010; DOI 10.1002/mop.25268
Autors: Tzuen-Hsi Huang, Pen-Li You, Kai-Li Huang
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A 7.9 GHz Low-Power PMOS Colpitts VCO Using the Gate Inductive Feedback
Abstract:
A low-power PMOS Colpitts voltage controlled oscillator (VCO) topology using the technique of gate inductive feedback is demonstrated. The topology enhances the negative conductance and overcomes the start-up difficulty of the conventional Colpitts VCO. This enables the Colpitts VCO to be operated in low-power consumption. The fabricated VCO operates from 7.4 to 7.9 GHz with 7% tuning range, a power consumption of 4.9 mW, and a supply voltage of 1.5 V. The measured phase noise at 1 MHz offset is 108.3 dBc/Hz at 7.9 GHz.
Autors: Hou, J.-A.;Wang, Y.-H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Apr 2010, volume: 20, issue:4, pages: 223 - 225
Publisher: IEEE
 
» A 77 GHz 90 nm CMOS Transceiver for FMCW Radar Applications
Abstract:
The first 77 GHz frequency modulated continuous wave (FMCW) radar transceiver IC with an accurate FMCW chirp signal generator using a 90 nm CMOS process is presented. To realize accurate FMCW radar system in CMOS, a PLL synthesizer based FMCW generator with chirp smoothing technique that is able to output linear FMCW frequency chirp using a nonlinear reference chirp signal supplied from a low spec/cost digital-oriented frequency reference is applied. The fabricated IC consists of an LNA, a down-conversion mixer with an output buffer, a driver amplifier, a power amplifier with power combiner, an LO distributer and an FMCW synthesizer. The measured FMCW signal from the proposed FMCW generator achieves 93 kHz frequency error (nonlinearity) at the 77 GHz chip signal. Radar performance of the IC has less than 1% ranging error from 1 m to 8 m distance from the measurement in a laboratory. These results show the transceiver achieves a fundamental function for radar applications with 520 mW power consumptions.
Autors: Mitomo, T.;Ono, N.;Hoshino, H.;Yoshihara, Y.;Watanabe, O.;Seto, I.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 928 - 937
Publisher: IEEE
 
» A 90 nm CMOS LC-Tank Divide-by-3 Injection-Locked Frequency Divider With Record Locking Range
Abstract:
This letter proposes a wide-locking range divide-by-3 injection-locked frequency divider fabricated in the 90 nm 1P9M CMOS technology. The divider consists of an nMOS cross-coupled p-core Armstrong LC oscillator and a center-tapped inductor in series with the pMOSFETs. The pMOSFETs are used as a linear and second harmonic mixer. At the supply voltage of 1 V, the free-running frequency is from 7.84 to 8.42 GHz, the current and power consumption of the divider without buffers are 4 mA and 4 mW respectively. At the incident power of 0 dBm, the locking range is 4.28 GHz (19.8%), from the incident frequency 19.52 to 23.8 GHz.
Autors: Jang, S.-L.;Chang, C.-W.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Apr 2010, volume: 20, issue:4, pages: 229 - 231
Publisher: IEEE
 
» A Background Self-Calibrated 6b 2.7 GS/s ADC With Cascade-Calibrated Folding-Interpolating Architecture
Abstract:
We have developed a 6b 2.7 GS/s folding ADC with on-chip background self-calibration in 90 nm CMOS technology. The ADC achieves high-speed operation of 2.7 GS/s at low power consumption of 50 mW from a 1.0 V power supply and the figure of merit (FOM) is 0.47 pJ/conversion-step. The key technique is a digital background self-calibration architecture which compensates for the large mismatch of small devices in the ADC and also corrects the ADC characteristics degradation during operation due to the drift of environmental factors such as temperature. This background calibration technique suited for multi-GHz operation is realized by two-channel ADC architecture and digital smoothing technique, which uses averaging of two comparator offsets and reconfiguration of reference connection. To minimize the power dissipation, a cascade-calibrated folding-interpolating architecture has been developed. It reduces the overall analog power of our design by 50%, compared with a conventional architecture which applies calibration only to preamplifiers. By utilizing these low-power techniques, we have successfully developed a low-power ADC with all functions including the background self-calibration control circuit.
Autors: Nakajima, Y.;Sakaguchi, A.;Ohkido, T.;Kato, N.;Matsumoto, T.;Yotsuyanagi, M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Apr 2010, volume: 45, issue:4, pages: 707 - 718
Publisher: IEEE
 
» A Bayesian model for the joint optimization of quality and maintenance decisions
Abstract:
We develop a model for the economic design of a Bayesian control chart for monitoring a process mean. The process may randomly suffer failures that result in a non-operating state, and thus call for an immediate corrective maintenance action, as well as assignable causes that shift the process mean to an undesirable level. Quality shifts, apart from poorer quality outcome and higher operational cost, also result in higher failure rate. Consequently, their removal, besides improving the outcome quality and reducing the quality-related cost, is also a preventive maintenance action since it reduces the probability of a failure. The proposed Bayesian model allows the determination of the design parameters that minimize the total expected quality and maintenance cost per time unit. The effectiveness of the proposed model is evaluated through the comparison of its expected cost against the optimum expected cost of the simpler variable-parameter Shewhart chart. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: George Nenes, Sofia Panagiotidou
Appeared in: Quality and Reliability Engineering International
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A broadband and high-gain metamaterial microstrip antenna
Abstract:
A broad bandwidth and high gain rectangular patch antenna was specifically designed in this paper using planar-patterned metamaterial concepts. Based on an ordinary patch antenna, the antenna has isolated triangle gaps and crossed strip-line gaps etched on the metal patch and ground plane, respectively. Demonstrated to have left-handed characteristics, the patterned metal patch and finite ground plane form a coupled capacitive-inductive circuit of negative index metamaterial. It is shown to have great impact on the antenna performance enhancement in terms of the bandwidth significantly broadened from a few hundred megahertz to a few gigahertz, and also in terms of high efficiency, low loss, and low voltage standing wave ratio. Experimental data show a reasonably good agreement between the simulation and measured results. This antenna has strong radiation in the horizontal direction for some specific applications within the entire band.
Autors: Li, Le-Wei;Li, Ya-Nan;Yeo, Tat Soon;Mosig, Juan R.;Martin, Olivier J. F.;
Appeared in: Applied Physics Letters
Publication date: Apr 2010, volume: 96, issue:16, pages: 164101 - 164101-3
Publisher: IEEE
 
» A Broadband High Efficiency High Output Power Frequency Doubler
Abstract:
An 8 to 30 GHz broadband high efficiency, high output power frequency doubler using 0.5 AlGaAs/InGaAs enhancement-mode pseudomorphic high electronic mobility transistor process is presented in this paper. A common-gate/common-source field effect transistor pair is employed in the balanced doubler. With an input power of 8 dBm, this work features a conversion gain of better than with a fundamental rejection of better than 13 dB over the operation bandwidth. The output 1 dB compression point and the saturation output power are higher than 7.3 and 10 dBm, respectively. This work presents the highest figure-of-merit (FOM) of 25.14 as compared to other previously reported broadband doublers.
Autors: Chang, H.-Y.;Chen, G.-Y.;Hsin, Y.-M.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Apr 2010, volume: 20, issue:4, pages: 226 - 228
Publisher: IEEE
 
» A Broadband Impedance Matching Method for Proximity-Coupled Microstrip Antenna
Abstract:
In a proximity-coupled microstrip antenna, when a laminate used is too thick for the antenna layer, the coupling will be decreased. And it is hard to achieve broadband impedance matching. The authors present a method to optimize impedance matching through narrow cavity backed configuration. A prototype antenna is designed with this method and fabricated. Simulation and measurement results indicate that the bandwidth of the antenna exceeds 40% . The antenna has a larger effective coupling as compared with the conventional proximity-coupled antenna without the narrow cavity backed configuration. It is easier to enhance the bandwidth with a thicker laminate. Meanwhile, this antenna is benefit for manufacturing and assembling to an array due to its simple configuration.
Autors: Sun, D.;You, L.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Apr 2010, volume: 58, issue:4, pages: 1392 - 1397
Publisher: IEEE
 
» A broadband linearization method using a novel opto-electrical predistorter for radio-over-fiber systems
Abstract:
A broadband linearization method with a novel opto-electrical predistorter was experimentally demonstrated. With the proposed method, the third-order intermodulation distortion was simultaneously enhanced by more than 10 dB for 510 MHz ranges and by 24 dB at 2.2 GHz without any change in electrical circuitry. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1638-1640, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25240
Autors: Yon-Tae Moon, Woon-Kyung Choi, Young-Wan Choi
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A Calculation Method for the Hybrid Electric Field Under UHVAC and UHVDC Transmission Lines in the Same Corridor
Abstract:
Parallel adjacent erection of UHVAC and UHVDC transmission lines in the same corridor will occur in the east of China. So the calculation method for the ac and dc hybrid electric field over the ground surface under this type of lines need to be studied so as to satisfy the requirements of engineering design and environmental protection. Based on the analysis of mutual influences between UHVAC and UHVDC transmission lines in the same corridor, a calculation method is proposed. The corresponding calculation results obtained with this method are shown as follows. Near the center of UHVAC and UHVDC transmission lines in the same corridor, especially in the side of UHVDC transmission lines, the change of voltages applied to ac conductor bundles can evidently affect the magnitude of the hybrid electric field; the hybrid electric field is sometimes enhanced and sometimes diminished, and the total effect appears subdued in an ac cycle. Except for the area close to the center of this type of lines, that whether the mutual influences between UHVAC and UHVDC transmission lines are considered or not can hardly affect the lateral distribution of the hybrid electric field.
Autors: Yang, Y.;Lu, J.;Lei, Y.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Apr 2010, volume: 25, issue:2, pages: 1146 - 1153
Publisher: IEEE
 
» A capacitive-sensing based simple serial mouse [Instrumentationnotes]
Abstract:
Capacitive sensing is a way of sensing changes by measuring changes in capacitance. We decided to build a very simple mouse using home-grown capacitive sensors. Using an analog microcontroller (the Analog Devices ADuC841), a few simple chips, and a few cents worth of copper we put together a very simple capacitive-sensing based mouse. Along the way, we learned quite a bit ¿ including how a serial mouse really works.
Autors: Engelberg, S.;Hazout, H.H.;Hirshowitz, J.;
Appeared in: IEEE Instrumentation & Measurement Magazine
Publication date: Apr 2010, volume: 13, issue:2, pages: 32 - 36
Publisher: IEEE
 
» A career in system-level design research [review of "Embedded System Design: Modeling, Synthesis, and Verification (Gajski, D.D. et al; 2009)]
Abstract:
This is a review of Embedded System Design: Modeling, Synthesis and Verification (by Daniel D. Gajski, Samar Abdi, Andreas Gerstlauer, and Gunar Schirner). The book introduces readers to embedded-systems design methodologies and tools, both those in use and those yet to come. It summaries the pioneering work of Daniel Gajski and colleagues in system-level design and shows both progress made and yet to be made in the field.
Autors: Martin, Grant;
Appeared in: IEEE Design & Test of Computers
Publication date: Apr 2010, volume: 27, issue:2, pages: 82 - 83
Publisher: IEEE
 
» A class of constant modulus algorithms for uniform linear arrays with a conjugate symmetric constraint
Abstract:
A class of constant modulus algorithms (CMAs) subject to a conjugate symmetric constraint is proposed for blind beamforming based on the uniform linear array structure. The constraint is derived from the beamformer with an optimum output signal-to-interferenceplus-noise ratio (SINR). The effect of the additional constraint is equivalent to adding a second step to the original adaptive algorithms. The proposed approach is general and can be applied to both the traditional CMA and its all kinds of variants, such as the linearly constrained CMA (LCCMA) and the least squares CMA (LSCMA) as two examples. With this constraint, the modified CMAs will...
Autors: Lei, Zhang , Wei, Liu , Richard J., Langley
Appeared in: Signal Processing
Publication date: Apr 2010
Publisher: Elsevier B.V.
 
» A Clinic for "Secure" Programming
Abstract:
Everyone has had problems with software. Some problems are particularly serious, such as the program on a satellite that contains an error, causing the loss of expensive equipment. So how can we develop better software? One way is to make good programming as much a part of learning computer science as good writing is a part of studying English and law. To test this idea, we developed a secure-programming clinic.
Autors: Bishop, Matt;
Appeared in: IEEE Security & Privacy
Publication date: Apr 2010, volume: 8, issue:2, pages: 54 - 56
Publisher: IEEE
 
» A Cloaking Metamaterial Based on an Inhomogeneous Linear Field Transformation
Abstract:
A new type of bianisotropic metamaterial is theoretically investigated on the basis of a linear inhomogeneous field transformation applied to an arbitrary free-space Maxwellian field. This transformation does not include any space compression as predicted by transformation optics, and consists of a linear combination with space-dependent coefficients of the electric and magnetic incident fields. Duality conditions are applied to select an appropriate shape of the constituent dyads, thus resulting in a metamaterial completely defined by two real differentiable functions of space and . When these functions satisfy the condition on the medium contour, the medium becomes globally lossless, and when imposing and at the same boundary, the medium does not scatter for any arbitrary incident field, that is, it becomes invisible. When an additional internal boundary is introduced with boundary conditions and , the medium becomes a perfect cloak. Explicit analytical results are given for an invisible sphere and for a spherical cloak to provide additional physical insight.
Autors: Maci, S.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Apr 2010, volume: 58, issue:4, pages: 1136 - 1143
Publisher: IEEE
 
» A Closed-Form Solution for Schedulability and Optimal Scheduling of Dual-Arm Cluster Tools With Wafer Residency Time Constraint Based on Steady Schedule Analysis
Abstract:
Because of wafer residency time constraints for cluster tools, it is very difficult to schedule them. This paper addresses their scheduling issues and conducts their schedulability and scheduling analysis. A Petri net (PN) model is developed to model them. With this model, to schedule a dual-arm cluster tool with wafer residency time constraints is to determine when and how long the robot should wait for. Based on the model, necessary and sufficient conditions under which the system is schedulable are presented. The conditions can be checked analytically. Meanwhile, an algorithm is developed for the optimal scheduling of dual-arm cluster tools. The algorithm finds an optimal periodic schedule with closed form expressions if it is schedulable. A method is also presented for the implementation of the obtained cyclic schedule by appropriately controlling the initial transient process. Examples are presented to show the application and power of the theory and algorithm.
Autors: Wu, N.;Zhou, M.;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Apr 2010, volume: 7, issue:2, pages: 303 - 315
Publisher: IEEE
 
» A Collusion-Resistant Routing Scheme for Noncooperative Wireless Ad Hoc Networks
Abstract:
In wireless ad hoc networks, routing needs cooperation of nodes. Since nodes often belong to different users, it is highly important to provide incentives for them to cooperate. However, most existing studies of the incentive-compatible routing problem focus on individual nodes' incentives, assuming that no subset of them would collude. Clearly, this assumption is not always valid. In this paper, we present a systematic study of collusion-resistant routing in noncooperative wireless ad hoc networks. In particular, we consider two standard solution concepts for collusion resistance in game theory, namely Group Strategyproofness and Strong Nash Equilibrium. We show that achieving Group Strategyproofness is impossible, while achieving Strong Nash Equilibrium is possible. More specifically, we design a scheme that is guaranteed to converge to a Strong Nash Equilibrium and prove that the total payment needed is bounded. In addition, we propose a cryptographic method that prevents profit transfer among colluding nodes, as long as they do not fully trust each other unconditionally. This method makes our scheme widely applicable in practice. Experiments show that our solution is collusion-resistant and has good performance.
Autors: Zhong, S.;Wu, F.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Apr 2010, volume: 18, issue:2, pages: 582 - 595
Publisher: IEEE
 
» A Combinatorial Study of Thin-Film Process Variables Using Microhotplates
Abstract:
A major goal of materials research over the past two decades has been the development of high-throughput methods for rapid discovery and optimization of processing routes. These methods rely on highly parallel materials synthesis to efficiently create libraries wherein at least one processing parameter has been systematically varied. Here, we demonstrate a method of using an array of microelectromechanical-systems (MEMS)-based microhotplates in the high-throughput optimization of a chemical vapor deposition (CVD) process. Electrical and thermal processing variables are independently controlled at each element of the array, both during and after deposition. In the experiment described, films were deposited on the microhotplates at 375 or 500 , with pulsed or continuous heating, and with voltage applied or not applied to the films. A 16-element microhotplate array was used, thus allowing a repeated two-level full factorial exploration of the experimental space. After deposition, sputter depth profile via X-ray photoelectron spectroscopy was used to determine the deposition rate of the films. Statistical modeling then determined the main effects and interaction effects of the growth conditions. Although applied here to the growth rate during CVD, the technology described is generally applicable for high-throughput study of the effects of thermal and electrical processing steps in thin-film manufacture. [2009-0137]
Autors: Lahr, D. L.;Hertz, J. L.;Semancik, S.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Apr 2010, volume: 19, issue:2, pages: 239 - 245
Publisher: IEEE
 
» A compact bandpass filter using interdigital and step-impedance hairpin resonators
Abstract:
A four-pole elliptic function bandpass filter is designed using miniaturized microstrip interdigital hairpin resonator and step-impedance hairpin resonator. Miniaturization hairpin resonators are realized by using interdigital structure and step-impedance structure having parallel coupled lines. The full-wave simulator IE3D is used to design the compact hairpin resonator and to calculate the coupling coefficient of the basic coupling strictures. The response of the fabricated filters using Al2O3 ([epsiv]r = 9.7, Q × f = 350000 GHz) and 0.6Sm(Co1/2Ti1/2)O3-0.4CaTiO3 ([epsiv]r = 37, Q × f = 43000 GHz) dielectric substrates are designed at a center frequency of 2 GHz. The compact size and the performance of this class of filter have been demonstrated. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1493-1495, 2010; DOI 10.1002/mop.25231
Autors: Cheng-Hsing Hsu, Chung-I. G. Hsu, Cheng-Chi Yu, Hsuan-An Ho
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A compact dual band branch line coupler with arbitrary power division ratio
Abstract:
This article presents a compact dual-band (DB) branch line coupler (BLC) with different power division ratio at arbitrary two frequency bands. In this article, we add a technique to satisfy transmission lines of conventional BLC with different impedance at two bands, while they are transformed to [pi]-type equivalent circuits. The design equations for DB BLC with different coupling coefficients at two bands are given. Furthermore, folded shape of shunt lines make about 77% circuit dimension comparing to conventional single-band BLC. A DB BLC operating different power division ratio at 0.9 and 2.0 GHz is demonstrated in excellent agreement with both circuit simulation and experimental results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1476-1480, 2010; DOI 10.1002/mop.25258
Autors: Kwisoo Kim, Jongsik Lim, Kwangsoo Kim, Dal Ahn
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A compact multilayer diplexer in LTCC substrate using LPF with multiple attenuation poles and wideband BPF
Abstract:
Recently, compact wideband BPFs for a UWB system have been studied actively. In this paper we propose a compact diplexer built into an LTCC substrate for a UWB system and 2.4-GHz wireless systems. First, a wideband BPF for a UWB system and an LPF with multiple attenuation poles for 2.4-GHz wireless systems are described. Second, we design matching circuits of a common port to retain the basic performance of both the BPF and the LPF. Third, in accordance with the results of the study, we design a compact diplexer built into an LTCC substrate. Finally, we verify the effectiveness of the proposed method by experiments. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(5): 24-32, 2010; Published online in Wiley InterScience (). DOI 10.1002/ecj.10210
Autors: Shimpei Oshima, Kouji Wada, Ryuji Murata, Yukihiro Shimakata
Appeared in: Electronics and Communications in Japan
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A Compact Six-Port Dielectric Resonator Antenna Array: MIMO Channel Measurements and Performance Analysis
Abstract:
MIMO systems ideally achieve linear capacity gain proportional to the number of antennas. However, the compactness of terminal devices limits the number of spatial degrees of freedom (DOFs) in such systems, which motivates efficient antenna design techniques to exploit all available DOFs. In this contribution, we present a compact six-port dielectric resonator antenna (DRA) array which utilizes spatial, polarization and angle diversities. To evaluate the proposed DRA array, a measurement campaign was conducted at 2.65 GHz in indoor office scenarios for four 6 6 multiple antenna systems. Compared to the reference system of monopole arrays which only exploit spatial diversity, the use of dual-polarized patch antennas at the transmitter enriches the channel's DOF in the non-line-of-sight scenario. Replacing the monopole array at the receiver with the DRA array that has a 95% smaller ground plane, the 10% outage capacity evaluated at 10 dB reference signal-to-noise ratio becomes equivalent to that of the reference system, due to the DRA's rich diversity characteristics. In the line-of-sight scenario, the DRA array gives a higher DOF than the monopole array as the receive counterpart to the transmit patch array. However, the outage capacity is 1.5 bits/s/Hz lower, due to the DRA array's lower channel gain.
Autors: Tian, R.;Plicanic, V.;Lau, B. K.;Ying, Z.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Apr 2010, volume: 58, issue:4, pages: 1369 - 1379
Publisher: IEEE
 
» A Compact Tri-Band Monopole Antenna With Single-Cell Metamaterial Loading
Abstract:
A compact tri-band planar monopole antenna is proposed that employs reactive loading and a “defected” ground-plane structure. The reactive loading of the monopole is inspired by transmission-line based metamaterials (TL-MTM), which enables the loaded antenna to operate in two modes. The first resonance exhibits a dipolar mode over the lower WiFi band of 2.40 GHz – 2.48 GHz, and the second resonance has a monopolar mode over the 5.15–5.80 GHz upper WiFi band. Full-wave analysis shows that the currents of the two modes are orthogonal to each other, resulting in orthogonal radiation patterns in the far field. The feature of a “defected” ground-plane, formed by appropriately cutting an -shaped slot out of one of the CPW ground-planes, leads to the third resonance that covers the WiMAX band at 3.30–3.80 GHz. Air bridges at the intersection between the antenna and the CPW feedline ensure a balanced current. A fabricated prototype has compact dimensions of 20.0 mm 23.5 mm 1.59 mm, and exhibits good agreement between the measured and simulated parameters and radiation patterns. The measured radiation efficiencies are 67.4% at 2.45 GHz, 86.3% at 3.50 GHz and 85.3% at 5.50 GHz.
Autors: Zhu, J.;Antoniades, M. A.;Eleftheriades, G. V.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Apr 2010, volume: 58, issue:4, pages: 1031 - 1038
Publisher: IEEE
 
» A comparative study of insulator materials exposed to high voltage AC and DC surface discharges
Abstract:
An experimental study was conducted, using the Inclined Plane Test method to determine the performance of typical power line insulator materials: RTV (Room Temperature Vulcanized) silicone rubber coated porcelain, HTV (High Temperature Vulcanized) silicone rubber and EPDM rubber. The constant voltage method was employed to evaluate the performance of the above samples when energized by ac and dc (both polarities) voltages. The relative performance of the different materials and the effect of the voltage types were investigated. The results show that the RTV silicone rubber coating exhibits the least erosion for ac voltage but shows extensive erosion in the case of negative dc voltage. The HTV silicone rubbers exhibit only minimal erosion when exposed to ac test voltage, but develop strong erosion under positive dc voltage, which can result in sample failure. EPDM experiences the least erosion for a negative dc voltage, but shows maximum erosion severity for ac voltage.
Autors: Heger, G.;Vermeulen, H.J.;Holtzhausen, J.P.;Vosloo, W.L.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Apr 2010, volume: 17, issue:2, pages: 513 - 520
Publisher: IEEE
 
» A comprehensive model of virtual competition in distribution energy systems
Abstract:
Drawbacks of traditional "rate of return" (ROR) regulation for distribution system operators (DSOs) have given birth to performance based regulations (PBRs), among which are price cap (PC), yardstick competition (YC), and quality regulation (QR). The PC method may be affected by information asymmetries between the regulator and DSOs and the integration of YC, a regulatory policy that makes the regulated DSO competing with a virtual competitor, partly solves this problem. QR also needs to be considered to ensure that the improvement of economics does not jeopardize quality. Thus, it seems appropriate to integrate the three PBRs to strive contemporaneously for economic and technical good performance.This paper aims to model the distribution system competition under the integrated PC, YC, and QR regulatory scheme, allowing for quantitative estimation of DSO's performance. We develop a comprehensive model to represent virtual competition under the integrated regulatory paradigm, capable of capturing the interaction among various DSOs, which is modeled as a Nash game where all the DSOs endeavor to reduce cost for profit maximization. The model is used to capture the impacts of various parameters on the technical and economic performances. An application of the model to real 5-DSOs case is provided and discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: Ettore Bompard, Roberto Napoli, Bo Wan, Ning Xie
Appeared in: European Transactions on Electrical Power
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A Comprehensive Technique for Determining the Intrinsic Light Yield of Scintillators
Abstract:
Precise knowledge of the intrinsic light yield of scintillating materials is important for characterizing, optimizing, and simulating scintillating detectors for radiation detection applications. We present here a comprehensive method for determining the intrinsic light yield of scintillating materials. By maintaining complete control over all aspects of photodetector response measurement, and through the use of a novel method for direct measurement of the light collection efficiency of the scintillator, we have successfully demonstrated that our technique allows for new levels of precision and understanding in the measurement of the intrinsic light yield of scintillating materials.
Autors: Salacka, J. S.;Bacrania, M. K.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Apr 2010, volume: 57, issue:2, pages: 901 - 909
Publisher: IEEE
 
» A computational fluid dynamics study of air mixing in a naturally ventilated livestock building with different porous eave opening conditions
Abstract:
Computational fluid dynamics models of wind-dominated and wind and buoyancy-influenced ventilation in a naturally ventilated livestock building were developed to investigate the mixing characteristics of the building and to determine its ventilation efficiency when different cladding materials are used at the eave openings. Firstly, CFD was used to provide insight into the air mixing characteristics of the building during wind-driven and wind and buoyancy-influenced ventilation. Secondly the relationship between an eave opening's resistance to airflow and indoor air mixing during wind-dominated ventilation was quantified, and finally the effect of eave opening conditions (i.e. eave cladding type, porosity, height) on building...
Autors: Tomás, Norton , Jim, Grant , Richard, Fallon , Da-Wen, Sun
Appeared in: Biosystems Engineering
Publication date: Apr 2010
Publisher: Elsevier B.V.
 
» A Constructive Proof of the Existence of Viterbi Processes
Abstract:
Since the early days of digital communication, hidden Markov models (HMMs) have now been also routinely used in speech recognition, processing of natural languages, images, and in bioinformatics. In an HMM , observations are assumed to be conditionally independent given a Markov process , which itself is not observed; moreover, the conditional distribution of depends solely on . Central to the theory and applications of HMM is the Viterbi algorithm to find a maximum a posteriori probability (MAP) estimate of given observed data . Maximum a posteriori paths are also known as the Viterbi paths, or alignments. Recently, attempts have been made to study behavior of the Viterbi alignments when . Thus, it has been shown that in some cases a well-defined limitin- g Viterbi alignment exists. While innovative, these attempts have relied on rather strong assumptions and involved proofs which are existential. This work proves the existence of infinite Viterbi alignments in a more constructive manner and for a very general class of HMMs.
Autors: Lember, J.;Koloydenko, A. A.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Apr 2010, volume: 56, issue:4, pages: 2017 - 2033
Publisher: IEEE
 
» A Contact-Less 2-Dimensional Laser Sensor for 3-Dimensional Wire Position and Tension Measurements
Abstract:
We have developed a contact-less two-dimensional laser sensor which combines position and tension measurements of wires with a diameter of order 0.2 mm. The sensor consists of commercially available laser pointers, lenses, color filters and photodiodes. In our application we have used this laser sensor in conjunction with an automated three-dimensional coordinate measuring machine (CMM). The device allows for a position measurement of wires in three dimensions with an accuracy of about 10 . At the same time the wire tension can be determined with an accuracy of 0.04 N. The device is operated at a distance of 150 mm from the wire.
Autors: Prall, M.;Hannen, V. M.;Johren, R.;Ortjohann, H.-W.;Reinhardt, M.;Weinheimer, C.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Apr 2010, volume: 57, issue:2, pages: 787 - 792
Publisher: IEEE
 
» A Contribution of Polarimetry to Satellite Differential SAR Interferometry: Increasing the Number of Pixel Candidates
Abstract:
This letter presents a general method for increasing the number of pixel candidates, those selected for processing in advanced differential SAR interferometry, by means of the exploitation of the polarimetric information provided by new satellite sensors. The algorithm is formulated for two different criteria of selection: the average coherence over the stack of interferograms and the amplitude dispersion index of the stack of images. Experimental results obtained with dual-pol images of TerraSAR-X over an urban area have demonstrated the expected improvement. The number of pixel candidates for an arbitrary threshold is 60% higher than that for single-pol data when using the average coherence and three times higher when using the dispersion index. The approach has also been compared to a selection based on a set of conventional channels (the copolar linear channels and the first two Pauli ones), showing a slight improvement for coherence selection and an important one for amplitude dispersion selection.
Autors: Navarro-Sanchez, V. D.;Lopez-Sanchez, J. M.;Vicente-Guijalba, F.;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Apr 2010, volume: 7, issue:2, pages: 276 - 280
Publisher: IEEE
 
» A cooperative diversity based handoff management scheme
Abstract:
Cooperative diversity has emerged as a promising technique to facilitate fast handoff mechanisms in mobile ad-hoc environments. The key concept behind a prominent cooperative diversity based protocol, namely, Partner-based Hierarchical Mobile IPv6 (PHMIPv6), is to enable mobile nodes anticipate handover events by selecting suitable partners to communicate on their behalves with Mobility Anchor Points (MAPs). In the original design of PHMIPv6, mobile hosts choose partners based on their signal strength. Such a naive selection procedure may lead to scenarios where mobile hosts lose communication with the selected partners before the completion of the handoff operations. In addition, PHMIPv6 overlooks security considerations, which can easily lead to vulnerable mobile hosts and/or partner entities. As a solution to these two shortcomings of PHMIPv6, this paper first proposes an extended version of PHMIPv6 called Connection Stability Aware PHMIPv6 (CSA-PHMIPv6). In CSA-PHMIPv6, mobile hosts select partners with whom communication can last for a sufficiently long time by employing the Link Expiration Time (LET) parameter. To tackle the security issues, the simple yet effective use of two distinct authentication keys is envisioned. Furthermore, to shorten the communication time between mobile hosts and their corresponding partners, a second handoff management approach called Partner Less Dependable PHMIPv6 (PLD-PHMIPv6) is proposed.
Autors: Taleb, T.;Letaief, K.B.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Apr 2010, volume: 9, issue:4, pages: 1462 - 1471
Publisher: IEEE
 
» A coupling system for connecting switch mode inverters to magnetic loops
Abstract:
This paper presents the analysis and design of a coupling system that allows magnetic loops to be connected efficiently to switch mode (SM) inverters. The coupling method involved has been traditionally used with linear amplifiers and transmission lines. The objective of this work is to develop a design procedure that is suitable for SM inverters. A detailed analysis is carried out on this coupling method and a design procedure is presented with an aim to optimize the operation of the inverter. The design procedure was used to build a 13.56 MHz prototype, the measurements from which they align very well with the theoretical predictions. Copyright © 2010 John Wiley & Sons, Ltd.
Autors: Michael P. Theodoridis, Stefan V. Mollov
Appeared in: International Journal of Circuit Theory and Applications
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A CPW-fed UWB monopole antenna and bifurcated antenna with a variable notching frequency
Abstract:
A small and compact ultra-wideband (UWB) monopole antenna with variable frequency band-notched characteristic is presented. The antenna consists of a coplanar waveguide fed triangular shaped radiating patch with a parasitic resonant structure in the conductor backed-plane. It is shown that the when the antenna is bisected, the bifurcated antenna exhibits virtually identical characteristics as the original UWB antenna, including variable frequency band-notched characteristics. It is also shown that the antenna's VSWR characteristics can be enhanced by deforming the ground-plane with periodic open end-slits. The fabricated antenna has a small size of 21.5 × 21 mm2, and the bifurcated antenna has a size of 10.75 × 21 mm2. The bifurcated antenna is substantially reduced in size by 50%. Both antennas operate over the frequency band between 2.7 and 11 GHz for VSWR < 2, whereas showing the band-rejection performance in the frequency band of 5.1-5.9 GHz. The proposed planar coplanar waveguide fed antennas are easily integrated with radio-frequency/microwave circuitry for low-manufacturing cost. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1545-1549, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25262
Autors: M. Naser-Moghadasi, L. Asadpor, R. Sadeghzadeh, Bal S. Virdee
Appeared in: Microwave and Optical Technology Letters
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A cubic-anvil high-pressure device for pulsed neutron powder diffraction
Abstract:
A compact cubic-anvil high-pressure device was developed for in situ neutron powder diffraction studies. In this device, a cubic shaped pressure medium is compressed by six anvils, and neutron beams pass through gaps between the anvils. The first high-pressure experiment using this device was conducted at J-PARC and clearly showed the neutron diffraction patterns of Pb. Combining the cubic-anvil high-pressure device with a pulsed neutron source will prove to be a useful tool for neutron diffraction experiments.
Autors: Abe, J.;Arakawa, M.;Hattori, T.;Arima, H.;Kagi, H.;Komatsu, K.;Sano-Furukawa, A.;Uwatoko, Y.;Matsubayashi, K.;Harjo, S.;Moriai, A.;Ito, T.;Aizawa, K.;Arai, M.;Utsumi, W.;
Appeared in: Review of Scientific Instruments
Publication date: Apr 2010, volume: 81, issue:4, pages: 043910 - 043910-5
Publisher: IEEE
 
» A cusp electron gun for millimeter wave gyrodevices
Abstract:
The experimental results of a thermionic cusp electron gun, to drive millimeter and submillimeter wave harmonic gyrodevices, are reported in this paper. Using a “smooth” magnetic field reversal formed by two coils this gun generated an annular-shaped, axis-encircling electron beam with 1.5 A current, and an adjustable velocity ratio α of up to 1.56 at a beam voltage of 40 kV. The beam cross-sectional shape and transported beam current were measured by a witness plate technique and Faraday cup, respectively. These measured results were found to be in excellent agreement with the simulated results using the three-dimensional code MAGIC.
Autors: Donaldson, C. R.;He, W.;Cross, A. W.;Li, F.;Phelps, A. D. R.;Zhang, L.;Ronald, K.;Robertson, C. W.;Whyte, C. G.;Young, A. R.;
Appeared in: Applied Physics Letters
Publication date: Apr 2010, volume: 96, issue:14, pages: 141501 - 141501-3
Publisher: IEEE
 
» A Darboux-Frame-Based Formulation of Spin-Rolling Motion of Rigid Objects With Point Contact
Abstract:
This paper investigates the kinematics of spin-rolling motion of rigid objects. This paper does not consider slipping but applies a Darboux frame to develop kinematics of spin-rolling motion, which occurs in a nonholonomic system. A new formulation of spin-rolling motion of the moving object is derived in terms of contravariant vectors, rolling velocity, and geometric invariants, including normal curvature, geodesic curvature, and geodesic torsion of the respective contact curve. The equation is represented with geometric invariants. It can be readily generalized to suit both arbitrary parametric surface and contact trajectory and can be differentiated to any order. Effect of the relative curvatures and torsion on spin-rolling kinematics is explicitly presented. The translation velocity of an arbitrary point on the moving object is also derived based on the Darboux frame.
Autors: Cui, L.;Dai, J. S.;
Appeared in: IEEE Transactions on Robotics
Publication date: Apr 2010, volume: 26, issue:2, pages: 383 - 388
Publisher: IEEE
 
» A Data-Mining Technique for Aerosol Retrieval Across Multiple Accuracy Measures
Abstract:
A typical approach in supervised learning is to select an accuracy measure and train a predictor that maximizes it. This can be insufficient in remote-sensing applications where predictor performance is often evaluated over multiple domain-specific accuracy measures. Here, we test the hypothesis that predictors can be trained to maximize performance over multiple accuracy measures. To do this, we evaluate several metalearning algorithms on the problem of aerosol optical depth (AOD) retrieval. The multiple accuracy measures included mean squared error, correlation, relative squared error, and fraction of satisfactory predictions. The proposed metalearning algorithms have a two-layer architecture, where the first layer consists of multiple neural networks, each trained using a different accuracy measure, and the second layer aggregates decisions of the first layer predictors. To evaluate AOD predictors, we used nearly 70 000 collocated data points whose attributes were radiances, solar and view angles, and terrain elevation from MODerate resolution Imaging Spectrometer (MODIS) instrument satellite observations and whose target AOD variable was obtained from the ground-based AEROsol robotic NETwork (AERONET) instruments. The data were collected at 221 AERONET locations over the globe in the period between 2005 and 2007. AOD prediction accuracies of neural networks were compared to the recently developed operational MODIS C005 retrieval algorithm and to several other data-mining methods. Results showed that neural networks are better at reproducing the test data than the operational retrieval algorithm and that predictors obtained by metalearning are robust over multiple accuracy measures.
Autors: Radosavljevic, V.;Vucetic, S.;Obradovic, Z.;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Apr 2010, volume: 7, issue:2, pages: 411 - 415
Publisher: IEEE
 
» A deadlock prevention approach for a class of timed Petri nets using elementary siphons
Abstract:
To solve the problem of deadlock prevention for timed Petri nets, an effective deadlock prevention policy based on elementary siphons is proposed in this paper. Without enumerating reachable markings, deadlock prevention is achieved by adding monitors for elementary siphons, increasing control depth variables when necessary, and removing implicit, liveness-restricted and redundant control places. The final supervisor is live. First, a timed Petri net is stretched into a stretched Petri net (SPN). Unchanging the system performance, each transition in the SPN has a unit delay time. Then the siphon-control-based approach is applied. Monitors computed according to the marking constraints are added to the SPN model to ensure all strict minimal siphons in the net invariant-controlled. A liveness-enforcing supervisor with simple structure can be obtained by reverting the SPN into a TdPN. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Autors: Jinwei Guo, Zhiwu Li
Appeared in: Asian Journal of Control
Publication date: Apr 2010
Publisher: Wiley InterScience
 
» A Deflation Procedure for Subspace Decomposition
Abstract:
A general deflation framework is described for the separation of a desired signal subspace of arbitrary dimensions from noisy multichannel observations. The method simultaneously uses single and multichannel priors to split the desired and undesired subspaces, even for coplanar (intersecting) subspaces. By appropriate use of signal priors, it can even extract signals from degenerate mixtures of signals and noise recorded from a few number of channels in low SNR scenarios, without the reduction of the data dimensions. As a case study, the performance of the proposed method is studied for the problem of extracting fetal cardiac signals from maternal abdominal recordings, over simulated and real data. A second case study deals with the degenerate problem of extracting diaphragmatic electromyogram from electrocardiograph artifacts. A provisional patent application based on this method has been filed.
Autors: Sameni, R.;Jutten, C.;Shamsollahi, M. B.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Apr 2010, volume: 58, issue:4, pages: 2363 - 2374
Publisher: IEEE
 
» A Design Method for Microstrip Directional Couplers Loaded With Shunt Inductors for Directivity Enhancement
Abstract:
An accurate design method is proposed for directivity enhancement of microstrip directional couplers loaded with shunt inductors. The parasitic effects of junction discontinuities in various parts of such microstrip directional couplers have critical effects especially on the directivity, and therefore they must be taken into account. Without proper modeling of these parasitic effects, directivity enhancement becomes extremely difficult especially for weak coupling levels. The demonstrated method of analysis can be applied to obtain exact designs of all previous microstrip directional couplers that are loaded symmetrically with series and/or shunt reactance for directivity enhancement, regardless of the coupling levels. Based on the proposed method, a 20-dB microstrip directional coupler is designed at 2.4 GHz. A maximum directivity of 56 dB has been measured, which is an improvement of 48 dB over a conventional microstrip directional coupler. A 16.3% bandwidth at 2.4 GHz has been measured in which the directivity remains above 20 dB, while the maximum variation in the coupling level is 0.5 dB. This is the first work to demonstrate directivity of more than 50 dB for a 20-dB microstrip directional coupler.
Autors: Lee, S.;Lee, Y.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Apr 2010, volume: 58, issue:4, pages: 994 - 1002
Publisher: IEEE
 

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