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  Home > Journals & magazines > Electronics Letters > Volume 49 Issue 18
  Volume 49, Issue 18, 29 August 2013
  Source: Electronics Letters, Volume 49, Issue 18, page: 1112 –1112
  DOI: 10.1049/el.2013.2699
  p. 1112 (1)
  Author(s): Carlos Thomaz
  DOI: 10.1049/el.2013.2700
  Source: Electronics Letters, Volume 49, Issue 18, page: 1113 –1113
  DOI: 10.1049/el.2013.2719
  p. 1113 (1)
  Source: Electronics Letters, Volume 49, Issue 18, page: 1114 –1114
  DOI: 10.1049/el.2013.2698
  p. 1114 (1)
  Author(s): B. Sanz-Izquierdo and E.A. Parker
  Source: Electronics Letters, Volume 49, Issue 18, p. 1117 –1118
  DOI: 10.1049/el.2013.2256
  Author(s): M.J. Hua ; P. Wang ; Y. Zheng ; S.L. Yuan
  Source: Electronics Letters, Volume 49, Issue 18, p. 1118 –1119
  DOI: 10.1049/el.2013.1669
  A compact triple-band coplanar waveguide (CPW)-fed antenna for WLAN/WiMAX applications is proposed. The radiation patch is fed by capacitive coupling of the top transmission line. By only using one metallic strip etched on the bottom of the substrate, tri-band resonances of the antenna are generated. The proposed antenna has a compact size of 30 × 27 mm2, which can provide stable omnidirectional radiation patterns in three bands. The measured − 10 dB impedance bandwidths are 150 MHz (2.39–2.54 GHz), 360 MHz (3.37–3.73 GHz) and 1170 MHz (5.02–6.19 GHz), which is suitable for WLAN/WiMAX applications.
  Author(s): Y.W. Wang ; G.M. Wang ; X.J. Gao ; C. Zhou
  Source: Electronics Letters, Volume 49, Issue 18, p. 1119 –1121
  DOI: 10.1049/el.2013.2180
  Author(s): Q. Li and A.P. Feresidis
  Source: Electronics Letters, Volume 49, Issue 18, p. 1121 –1123
  DOI: 10.1049/el.2013.1965
  A miniaturised double-layer slit-patch structure is introduced for decoupling two closely spaced co-planar waveguide-fed printed monopoles with a common ground. The double-layer structure consists of a slit etched on the common ground between the antennas and a conducting dipole element printed on a very thin dielectric film separating the two layers. Simulated results of the antennas' performance as well as measurements of fabricated prototypes are presented.
  A priori-driven multivariate statistical approach to reduce dimensionality of MEG signals
  Author(s): C.E. Thomaz ; E.L. Hall ; G.A. Giraldi ; P.G. Morris ; R. Bowtell ; M.J. Brookes
  Source: Electronics Letters, Volume 49, Issue 18, p. 1123 –1124
  DOI: 10.1049/el.2013.1796
  A magnetoencephalography (MEG) multivariate data exploratory analysis is described and implemented that combines the variance criterion used in principal component analysis with some prior knowledge about the sensory experimental task. By using the idea of rearranging the data matrix in classification pairs that correspond to the time-varying representation of either stable or stimulus phases of the specific task, the feature extraction method is constrained reducing significantly the number of principal components necessary to represent most of the total variance explained by the MEG signals.
  Author(s): Jungmoon Kim and Chulwoo Kim
  Source: Electronics Letters, Volume 49, Issue 18, p. 1125 –1126
  DOI: 10.1049/el.2013.1479
  Low-noise and high-gain wideband LNA with gm -boosting technique
  Author(s): Zhiqun Li ; Liang Chen ; Zengqi Wang ; Chenjian Wu ; Jia Cao ; Meng Zhang ; Chong Wang ; Yang Liu ; Zhigong Wang
  Source: Electronics Letters, Volume 49, Issue 18, p. 1126 –1128
  DOI: 10.1049/el.2013.1687
  A broadband low-noise amplifier (LNA) is proposed. The active gm -boosting technique is utilised to reduce the common-gate (CG) LNA noise figure and improve gain. An implemented prototype using 0.13 μm CMOS technology is evaluated using on-wafer probing. S 11 and S 22 are below − 10 dB across 0.1–5 GHz. Measurements show a power gain of 18.3 dB with a − 3 dB bandwidth from 100 MHz to 2.1 GHz and an IIP3 of − 7 dBm at 2 GHz. The measured noise figure is better than 2.5 dB below 2.1 GHz, better than 4.5 dB below 5 GHz and at 500 MHz it obtains its minimum value 1.8 dB. The LNA consumes 14 mW from 1.5 V supply and occupies an area of 0.04 mm2.
  Author(s): F. Tavernier ; P. Moreira ; K. Poltorak
  Source: Electronics Letters, Volume 49, Issue 18, p. 1128 –1130
  DOI: 10.1049/el.2013.1925
  A robust and fully integrated solution to calibrate the voltage controlled oscillator frequency to the data rate frequency in a clock and data recovery is described. As such, no external reference frequency or a separate reference phase-locked loop is required. The proposed calibration circuit has been designed in a 130 nm CMOS technology. It shows a very low temperature dependency below 100 ppm °C−1.
  Clock buffer with supply noise active compensation for reduced period jitter
  Source: Electronics Letters, Volume 49, Issue 18, p. 1130 –1131
  DOI: 10.1049/el.2013.1178
  A simple circuit that actively compensates supply noise and reduces period jitter in CMOS clock buffers is presented. The locally sensed supply noise modulates a current injected in the buffer output node during transitions. By injecting the current in opposite phase to the supply noise, the transient variations are counterbalanced and the jitter removed. Designed in a 28 nm CMOS technology, a chain of 16 inverters using the proposed circuit shows a period jitter up to three times smaller than that of an equally long chain of basic inverters. Conventional local supply noise filtering would require approximately 70 times the area used by the proposed circuit to achieve similar performance.
  Design of four-state inverter using quantum dot gate-quantum dot channel field effect transistor
  Source: Electronics Letters, Volume 49, Issue 18, p. 1131 –1133
  DOI: 10.1049/el.2013.0570
  Quaternary logic can be implemented using quantum dot gate-quantum dot channel field effect transistors (QDG-QDCFETs) which produce four states in their transfer characteristics. A circuit model is used to simulate a four-state state inverter which is the basic building block of any multi-valued logic (MVL) circuit design. A basic problem of MVL implementation is the noise margin. The stable nature of the transfer characteristics of the QDG-QDCFET can make them a promising circuit element in future MVL circuit design. Comparison of fabricated device characteristics and the model data is shown.
  Low complexity lowpass linear-phase multiplierless FIR filter
  Author(s): V.D. Pavlović ; D.S. Antić ; S.S. Nikolić ; S.Lj. Perić
  Source: Electronics Letters, Volume 49, Issue 18, p. 1133 –1135
  DOI: 10.1049/el.2013.1791
  A new class of lowpass linear-phase FIR filter function given in an explicit compact form is introduced. First, the general form of a new class of nth-order difference equations with all real coefficients equals one is proposed, and after that the simple frequency sampling structure for any odd and even orders of the filter is designed. Finally, several simulation experiments have been performed in order to compare this filter with other known filters for the same values of free real integer parameters. It should be highlighted that the new filters compare favourably even with the already existing filters, because they have an insert attenuation of 158 dB, 15.1681% lower cutoff frequency of the passband of the filter, and 18.5313% lower cutoff frequency of the stopband of the filter, for an insert loss of 100 dB.
  Unified split-step precise integration time-domain method for dispersive media
  Author(s): Qi Liu ; Xikui Ma ; Feng Chen
  Source: Electronics Letters, Volume 49, Issue 18, p. 1135 –1136
  DOI: 10.1049/el.2013.2101
  Based on the use of auxiliary differential equations, a unified split-step precise integration time-domain (SS-PITD) method is proposed for modelling wave propagation in linear dispersive media. The unification of this method is achieved by using a general expression to represent the Debye, Lorentz and Drude dielectric medium models. Moreover, due to the introduction of the SS scheme, the original two-dimensional (2D) or 3D electromagnetic problem reduces to a set of 1D sub-problems which can be efficiently solved by using the conventional PITD algorithm. It leads to a great reduction in the requirement of computation time and storage space. The proposed method is verified with a numerical example and compared with the finite-difference time-domain method.
  Fast and efficient blind image quality index in spatial domain
  Author(s): Shuhong Jiao ; Huan Qi ; Weisi Lin ; Weihe Shen
  Source: Electronics Letters, Volume 49, Issue 18, p. 1137 –1138
  DOI: 10.1049/el.2013.1837
  A fast and efficient method [fast efficient blind (FEB)] for no-reference image quality assessment (IQA) is presented. Two new features, log-energy and variance, are proposed in the spatial domain, which make the IQA algorithm faster and more efficient. FEB obviates the training process of distortion images and subjective opinion scores due to the properties of the new features. The experiment shows that the proposed method outperforms conventional methods in terms of both accuracy and execution speed and is also consistent with the subjective assessment of human beings. Owing to the simplicity of the features proposed, FEB can realise real-time IQA completely.
  Specularity detection method based on MSER
  Author(s): H. Zhu ; C. Gao ; Y. Guo ; Y. Shao
  Source: Electronics Letters, Volume 49, Issue 18, p. 1138 –1140
  DOI: 10.1049/el.2013.2306
  A new algorithm for specularity detection using a single image, which is based on the maximally stable extremal regions (MSER) detector, is presented. This algorithm takes full advantage of the characteristics of specularity and requires no assumptions. For this reason, it separates specularities very well regardless of the illumination condition and the surface material. To illustrate the effectiveness of the prposed algorithm, experiments are performed using the images of both dielectric and metal surfaces. Experimental results show that the presented approach outperforms the traditional methods from the point of view of sensitivity to correctness.
  Automatic foreground extraction via joint CRF and online learning
  Author(s): W. Zou ; K. Kpalma ; J. Ronsin
  Source: Electronics Letters, Volume 49, Issue 18, p. 1140 –1142
  DOI: 10.1049/el.2013.2100
  A novel approach is proposed for automatic foreground extraction which aims to segment out all foreground objects from the background in the image. The segmentation problem is formulated as an iterative energy minimisation of the conditional random field (CRF), which can be efficiently optimised by graph-cuts. The energy minimisation is initialised and modulated by a soft location map predicted by a discriminative classifier which is learned on-the-fly from a set of segmented exemplar images. Iteratively minimising the CRF energy leads to optimal segmentation. Experimental results on the Pascal visual object classes (VOC) 2010 segmentation dataset, a widely acknowledged difficult dataset, show that the proposed approach outperforms the state-of-the-art techniques.
  Author(s): J. Byun ; Y. Jung ; J. Kim
  Source: Electronics Letters, Volume 49, Issue 18, p. 1142 –1143
  DOI: 10.1049/el.2013.0936
  Author(s): S. Gruenwedel ; N.I. Petrović ; L. Jovanov ; J.O. Niño-Casta-ñeda ; A. Pižurica ; W. Philips
  Source: Electronics Letters, Volume 49, Issue 18, p. 1143 –1145
  DOI: 10.1049/el.2013.1944
  High-throughput CABAC codec architecture for HEVC
  Author(s): Yongseok Choi and Jongbum Choi
  Source: Electronics Letters, Volume 49, Issue 18, p. 1145 –1147
  DOI: 10.1049/el.2013.1811
  A VLSI architecture of a context adaptive binary arithmetic coding (CABAC) entropy codec for high-efficiency video coding (HEVC), the next generation video coding standard, is presented and analysis of its performance in terms of effective processing throughput, i.e. bin/s, is provided. For high throughput, the architecture is designed to process up to two regular bins per unit time while minimising pipeline stall due to inherent dependencies of CABAC through various optimisations including context forwarding and speculative decoding. The experiments show that the effective throughput is achieved up to 1.60 bins or 1.41 bits per cycle, which corresponds to 469.5 Mbit/s at the operating frequency of 333 MHz, under practical video coding environments.
  Author(s): YoungJae Kwon and Jong-Seok Lee
  Source: Electronics Letters, Volume 49, Issue 18, p. 1147 –1148
  DOI: 10.1049/el.2013.1951
  Combination of step sizes for affine projection algorithm with variable mixing parameter
  Author(s): Jong Hyun Choi ; Hyeonwoo Cho ; Jae Jin Jeong ; Sang Woo Kim
  Source: Electronics Letters, Volume 49, Issue 18, p. 1149 –1150
  DOI: 10.1049/el.2013.1790
  An algorithm that introduces a novel scheme for the combination of the two adaptation terms of the affine projection algorithm with different step sizes is proposed. The mixing parameter of the proposed algorithm is determined by minimising the mean-square deviation. The simulation results show that the proposed algorithm has a faster convergence rate and a smaller steady-state error than other existing combination algorithms.
  Author(s): V. Rajovic ; G. Savic ; V. Ceperkovic ; M. Prokin
  Source: Electronics Letters, Volume 49, Issue 18, p. 1150 –1152
  DOI: 10.1049/el.2013.0931
  Subband transformation coefficients are typically computed by first filtering and downsampling of an input uncompressed signal and then subsequently filtering and downsampling the result intermediate signals with a set of lowpass and highpass filters. State-of-the-art subband transformers are complex, which increases consumed power. A novel method for significantly decreasing the complexity of subband transformers to a minimum is presented. This solution was implemented in a field programmable gate array, together with various methods for compression and decompression.
  Author(s): V. Savaux ; Y. Louët ; M. Djoko-Kouam ; A. Skrzypczak
  Source: Electronics Letters, Volume 49, Issue 18, p. 1152 –1154
  DOI: 10.1049/el.2013.1993
  An expression of the minimum mean square error (MMSE) of the linear MMSE channel estimation is given in the case of a non-invertible channel covariance matrix, as in single-input single-output (SISO) OFDM system. A matrix expression, already proposed for a multi-input multi-output OFDM system in a previous article, is not valid in SISO. A new proof is then proposed, by deriving a scalar expression of the MMSE, which leads to solve an optimisation problem. Furthermore, we show that the proposed solution is the global minimum. Simulations validate the proposed development.
  Author(s): L. Sommervogel ; L. El Sahmarany ; L. Incarbone
  Source: Electronics Letters, Volume 49, Issue 18, p. 1154 –1155
  DOI: 10.1049/el.2013.1042
  A new post-processing approach which aims at reducing the dispersion effect of the wave travelling inside a waveguide is presented. The main objective is to improve the time domain reflectometry measurements performed over long-distance cables, relative to the wavelength λ. A real-case scenario is presented so that the gain of this method can be appreciated.
  Author(s): Hui Wang ; Yu-Qian Yang ; Wei Kang ; Wen Wu ; Kam-Weng Tam ; Sut-Kam Ho
  Source: Electronics Letters, Volume 49, Issue 18, p. 1156 –1157
  DOI: 10.1049/el.2013.1319
  A compact ultra-wideband differential bandpass filter (BPF) based on a self-coupled ring resonator is proposed. The self-coupled line contributes to not only three poles in differential-mode (DM) but also three zeros in common-mode (CM) offering both a wide differential passband and good CM suppression. A fabricated filter with a 3 dB fractional bandwidth of 118% for the DM and insertion loss greater than 18 dB for the CM has been designed and measured. This filter is only 30.4 × 1.0 mm (1.0λ 0 × 0.03λ 0) and it is only 15% of the size of the most reported differential BPFs. The simulated and measured results are in good agreement.
  On-chip dual-band bandpass filter on a GaAs substrate
  Author(s): Hsuan-Ling Kao ; Xin Dai ; Xiu Yin Zhang ; Cheng-Lin Cho ; Chih-Sheng Yeh ; Hsien-Chin Chiu
  Source: Electronics Letters, Volume 49, Issue 18, p. 1157 –1159
  DOI: 10.1049/el.2013.1128
  A dual-band bandpass filter in a millimetre-wave band that uses 0.5 μm GaAs pHEMT technology with two sets of stepped-impedance resonators, which results in a reduction in size, is presented. The two passband frequencies can be flexibly controlled by adjusting the lengths of the two sets of resonators. Two bandwidths can be tuned independently, using external quality factors and coupling coefficients. The fractional 1-dB bandwidths at 60 and 77 GHz are 8.6 and 4.1%, respectively. The measured S 21 values at 60 and 77 GHz are − 2.26 and − 3.9 dB. Good performance is obtained in terms of the excellent microwave properties of the semi-insulating GaAs substrate, which makes this system attractive for wireless communication applications.
  Compact microstrip lowpass filter with sharp roll-off and ultra-wide stop-band
  Author(s): M. Hayati ; A. Abdipour ; A. Abdipour
  Source: Electronics Letters, Volume 49, Issue 18, p. 1159 –1160
  DOI: 10.1049/el.2013.1622
  A compact microstrip lowpass filter (LPF) with sharp roll-off and ultra-wide stop-band bandwidth is presented. The structure consists of high-impedance meandered transmission lines loaded by triangular and polygonal resonant patches. The cutoff frequency of the proposed LPF is 2.44 GHz and the measured results show good performance such as sharp roll-off, good insertion loss and an ultra-wide stop-band from 2.53 to 35 GHz with the insertion-loss higher than 20 dB. There is a good agreement between the electromagnetic-simulation and measurement results.
  Author(s): K. Song ; F. Zhang ; S. Hu ; Y. Fan
  Source: Electronics Letters, Volume 49, Issue 18, p. 1160 –1162
  DOI: 10.1049/el.2013.1991
  Miniaturised dual-wideband bandpass filter using novel dual-band coupled-line sections
  Author(s): Jin Xu and Wen Wu
  Source: Electronics Letters, Volume 49, Issue 18, p. 1162 –1163
  DOI: 10.1049/el.2013.1665
  A novel dual-wideband bandpass filter (BPF) by using the proposed dual-band open stub-loaded coupled-line section is presented. The proposed dual-band BPF has a symmetrical frequency response along the designing frequency f 0, and the transmission zero at f 0 improves the filter band-to-band isolation significantly. As an example, a dual-wideband BPF for 2.4 GHz WLAN and 6.8 GHz RFID applications is designed, fabricated and measured. The fabricated filter has the merits of simple topology, compact size, good return loss, low insertion loss and high isolation. The measurement agrees well with the simulation.
  Two-dimensional crest factor reduction for performance improvement of concurrent dual-band power amplifiers
  Author(s): Xiaofan Chen ; Silong Zhang ; Wenhua Chen
  Source: Electronics Letters, Volume 49, Issue 18, p. 1163 –1165
  DOI: 10.1049/el.2013.1650
  A two-dimensional crest factor reduction (2D-CFR) is proposed to improve the performance of concurrent dual-band power amplifiers (PAs). Experimental measurements are performed on a 1.9–2.6 GHz concurrent dual-band LTE PA by using the proposed 2D-CFR and conventional 1D-CFR, respectively. Measured results after 2D digital predistortion (2D-DPD) show that the output power with the proposed 2D-CFR is increased by 10%, the efficiency is improved from 28.1 to 30.6% and the error vector magnitude is reduced from 3.46 to 2.67%, indicating a significant performance improvement.
  High-resolution technique for simultaneous measurement of phase noise of multi-wavelength optical systems
  Author(s): A.P. Anthur and D. Venkitesh
  Source: Electronics Letters, Volume 49, Issue 18, p. 1165 –1167
  DOI: 10.1049/el.2013.1784
  A technique is proposed and demonstrated to simultaneously measure the phase noise of four-wave mixing components, using a combination of heterodyning and delayed self-heterodyning techniques.
  Inertial micro-switch capable of prolonging contact time
  Author(s): Kangfa Deng ; Weiguo Su ; Song Li ; Yating Zhang ; Wei Zhang
  Source: Electronics Letters, Volume 49, Issue 18, p. 1167 –1168
  DOI: 10.1049/el.2013.0872
  A novel inertial micro-switch capable of prolonging contact time and reducing the contact-bouncing effect is proposed. Based on the nonlinear-spring shock stop, both the moveable and the fixed electrodes are made flexible by using a moveable contact point and a cascaded beam, respectively. The switch was successfully fabricated by bulk micromachining process. From the drop hammer test, the switch-on time increased with an increase of the input acceleration and reached a maximum of 335 μs, which is over 30 times larger than that of the traditional switch; and no bounce occurred.
  Ultra-dense and ultra-low power microhotplates using silica aerogel
  Author(s): M. Seyedjalali ; S. Kumar ; M.R. Madani
  Source: Electronics Letters, Volume 49, Issue 18, p. 1168 –1170
  DOI: 10.1049/el.2013.1389
  A thin film of silica aerogel has been spin coated on silicon wafers to investigate its super thermal insulating capability. The temperature of the thin film heaters fabricated on the aerogel coated wafer is measured at different applied powers. Simulations are performed to compare the aerogel coated wafers with the micromachined wafers. Both experimental and simulation results show better heat insulation for aerogel coated wafers as compared with simulated micromachined wafers. The measurement and simulation results of aerogel coated wafers are in good agreement. The aerogel film can replace the air cavity created by conventional micromachining of wafers to save power and chip area in metal oxide gas sensor arrays.
  Self-adaptive load technology for multiple-string LED drivers
  Author(s): Ning Ning ; Wen Bin Chen ; De Jun Yu ; Chun Yi Feng ; Cheng Bi Wang
  Source: Electronics Letters, Volume 49, Issue 18, p. 1170 –1171
  DOI: 10.1049/el.2013.2093
  A self-adaptive load technology for multiple-string LED drivers is presented. Directly operating from an AC voltage, the proposed technology realises soft switching with a self-adaptive load resistor, so that the LED avoids the current glitch during current switching. Thus, the quality of lighting, the lifetime and the performance of the LED are improved. An AC LED driver using the proposed technology was fabricated in a 0.25 µm BCDMOS process and tested with a five-string LED. The measured results show that the power factor is 0.998 (0.997) with 5.1% (7.2%) total harmonic distortion under 19 W 110 V/AC (220 V/AC) condition.
  Author(s): Q.T. Le ; D. Briggmann ; F. Kueppers
  Source: Electronics Letters, Volume 49, Issue 18, p. 1171 –1173
  DOI: 10.1049/el.2013.1996
  Tuning power spectrum of semiconductor and intracavity-etalon based modelocked laser via detuning
  Author(s): D.S. Seo ; D.E. Leaird ; A.M. Weiner
  Source: Electronics Letters, Volume 49, Issue 18, p. 1173 –1175
  DOI: 10.1049/el.2013.2135
  A report is presented on the tuning of the frequency envelope of a broadband comb source generated from a semiconductor-based modelocked ring laser with an intracavity high finesse Fabry-Pérot etalon (FPE). By deliberately adjusting the matching condition between FPE transmission peaks and lasing optical comb frequencies, ∼ 7 nm tuning of more than 200 optical frequency comb lines spaced by 10 GHz is achieved.
  Author(s): H.C. Sun ; Z. Zhong ; Y.X. Guo
  Source: Electronics Letters, Volume 49, Issue 18, p. 1175 –1176
  Fast algorithm based on self-resonant frequency for decoupling capacitor selection
  Author(s): Xiu Qin Chu ; Yong Jia Lin ; Bo Hua Pan ; Songsong Zhang
  Source: Electronics Letters, Volume 49, Issue 18, p. 1176 –1178
  DOI: 10.1049/el.2012.3744
  A fast algorithm based on the self-resonant frequency for decoupling capacitor (decap) selection is proposed and verified experimentally. The proposed algorithm has been compared with the genetic algorithm (GA). Results show that they both give quality and similar decoupling solutions, but the proposed algorithm is superior to the GA in computation speed.
  Ambiguity analysis of HD FM waveforms for use in passive radar
  Author(s): G.E. Smith ; J.L. Garry ; R.L. Ewing ; C.J. Baker
  Source: Electronics Letters, Volume 49, Issue 18, p. 1178 –1179
  DOI: 10.1049/el.2013.1582
  Analogue VHF waveforms have been used extensively as signals of opportunity in passive radar concepts. They have time-varying ambiguity properties determined by the instantaneous nature of the broadcast content and correspondingly this results in a time-varying radar performance. In this reported work, the ambiguity properties of high definition (HD) FM signals are examined. It is shown that the digital modulation imposed on these transmissions results in more stable ambiguity properties better suited to reliable and consistent passive radar performance.
  Clutter rank estimation rule for MIMO radar with arbitrary transmitted waveform synthetic strategies
  Author(s): Cunqian Feng ; Linrang Zhang ; Dong Zhang ; Yiduo Guo
  Source: Electronics Letters, Volume 49, Issue 18, p. 1180 –1181
  DOI: 10.1049/el.2013.1844
  A computational-efficient estimated rule of clutter rank for multiple-input multiple-output (MIMO) radar with arbitrary transmitted waveform synthetic strategies is presented and proved. It is suitable for both conventional phased array radar and MIMO radar with a uniform sparse or non-uniform sparse transmitting subarray, and is also valuable for the design of optimal waveform synthetic strategies and space–time adaptive processing algorithms. The effectiveness of the proposed rule is verified by simulation results.
  Measurement of normalised radar cross-section of polystyrene foam at 60 GHz
  Author(s): K. Kaneko ; K. Seki ; T. Ihara
  Source: Electronics Letters, Volume 49, Issue 18, p. 1181 –1183
  DOI: 10.1049/el.2013.1603
  The backscattering measurement of a rectangular solid volume of polystyrene foam (width: 0.92 m; height: 0.9 m; depth: 1.82 m) carried out at frequencies ranging from 59 to 60 GHz is described with horizontal polarisation for both transmission and reception antennas. The volume fraction of polystyrene in the measured material is about 0.01. The normalised radar cross-section of the measured polystyrene foam sample is estimated as 2.9 × 10 − 3(±3 × 10 − 4) m2/m3 by using the range-resolved data of the backscattered power arising from inside of the polystyrene foam volume. When using polystyrene foam as a support for radar targets in radar measurements, this result is considered useful for quantitatively estimating the intensity of the unwanted backscattered waves due to the foam.
  SAR image despeckling using adaptive multiscale products thresholding in directionlet domain
  Source: Electronics Letters, Volume 49, Issue 18, p. 1183 –1184
  DOI: 10.1049/el.2013.2186
  A directionlet transform (DT)-based multiscale products thresholding is presented which uses a generalised cross-validation (GCV) technique for synthetic aperture radar image despeckling. DT has gained popularity over the past few years as an anisotropic, critically sampled and perfect reconstruction transform with directional vanishing moments along any two directions. In this reported work, the multiscale correlation of DT is exploited by multiplying the adjacent scale coefficients to enhance edge structures while weakening noise. An optimal subband adaptive threshold based on GCV is then computed using this multiscale product. The despeckled image is finally synthesised by using the threshold applied DT coefficients. The employment of DT results in the significant features in images evolving with high magnitudes across scales, while the noise decays rapidly. The proposed scheme outperforms many of the traditional despeckling schemes in terms of speckle reduction and edge preservation.
  Source: Electronics Letters, Volume 49, Issue 18, p. 1184 –1186
  Outage probability analysis of signal space cooperative communications over Nakagami-m fading channels
  Author(s): Tao Lu ; Jianhua Ge ; Ye Yang ; Yang Gao
  Source: Electronics Letters, Volume 49, Issue 18, p. 1186 –1188
  DOI: 10.1049/el.2013.0011
  The outage probability of an efficient signal space cooperative (SSC) scheme is investigated over general independent and non-identically distributed Nakagami-m fading channels. In particular, the exact outage probability expression is derived for arbitrary values of the fading parameter m (m ≥ 0.5). Furthermore, an asymptotic approximation for the outage probability is obtained, which clearly shows the diversity and coding gains of the SSC scheme, and therefore can offer important theoretical guidance to scheme designers. Simulation results are provided to verify the theoretical analysis.
  Resolving phase measurement ambiguity in presence of coloured noise
  Author(s): Wenchao Li ; Xuezhi Wang ; Xinmin Wang ; Bill Moran
  Source: Electronics Letters, Volume 49, Issue 18, p. 1188 –1190
  DOI: 10.1049/el.2013.1209
  Recovering a distance from ambiguous phase measurements observed at multiple signal frequencies involves the estimation of both integer and scalar quantities simultaneously. The problem is optimally addressed by existing methods only when the measurement noise is IID. A noise 'whitening' procedure is derived with a least-square estimation structure inherent to the Lattice method proposed previously which thus extends this Lattice-based algorithm to cope with coloured phase measurement noise in an optimal manner demonstrated via simulation.