Electronics Letters
Volume 52, Issue 5, 03 March 2016
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Volume 52, Issue 5
03 March 2016
- Features
- Antennas and propagation
- Biomedical technology
- Circuits and systems
- Control engineering
- Dielectrics
- Image and vision processing and display technology
- Information and communications
- Microwave technology
- Optical communication
- Photonics
- Power electronics, energy conversion and sustainability
- Radar, sonar and navigation
- Semiconductor technology
- Signal processing
- Wireless communications
- Errata
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- Source: Electronics Letters, Volume 52, Issue 5, page: 332 –332
- DOI: 10.1049/el.2016.0467
- Type: Article
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- Source: Electronics Letters, Volume 52, Issue 5, page: 332 –332
- DOI: 10.1049/el.2016.0466
- Type: Article
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- Source: Electronics Letters, Volume 52, Issue 5, page: 333 –333
- DOI: 10.1049/el.2016.0463
- Type: Article
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in brief
interview
simple terahertz
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- Author(s): Chao Chen and Jianhui Wu
- Source: Electronics Letters, Volume 52, Issue 5, p. 335 –336
- DOI: 10.1049/el.2015.3881
- Type: Article
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A 0.6-V 2.1-mW RF receiver with regular threshold transistors is presented. A passive mixer which is built on low-power current-buffer is designed to build the RF front-end. A master–slave operational trans-conductance amplifier (OTA) structure which provides sufficient common-mode rejection ratio (CMRR) by auto-adjusting the gate of the triode-region biased tail current source is proposed as the building block of the intermediate-frequency (IF) modules. The proto-type of the RF receiver is designed and fabricated in Semiconductor Manufacturing International Corporation (SMIC) 65 nm CMOS process. The measurement indicates that the receiver covers a bandwidth from 1 to 1.5 GHz, achieving a voltage gain of 32 dB and a noise figure (NF) of 10 dB.
- Author(s): R. Chandel and A.K. Gautam
- Source: Electronics Letters, Volume 52, Issue 5, p. 336 –338
- DOI: 10.1049/el.2015.3889
- Type: Article
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A novel MIMO sharp band-notched antenna with high isolation for UWB applications is presented. The antenna consists of two antenna elements with an overall area of 18 × 36 mm2. A T-shaped stub is extruded in the ground plane to improve isolation and an L-shaped stub to introduce band-notched function C-band (3.62–4.77 GHz). The designed antenna possesses a low mutual coupling of <−20 dB over the operating band from 2.9 to 20 GHz. The performance of this antenna is studied in terms of isolation between the two ports, radiation pattern, efficiency, realised gain, and envelope correlation coefficient.
- Author(s): Jie Zhuang ; Qian Ye ; Qiushi Tan ; Abdulrahman Hussein Ali
- Source: Electronics Letters, Volume 52, Issue 5, p. 338 –340
- DOI: 10.1049/el.2015.3844
- Type: Article
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Although the majority of the existing robust adaptive beamformers focus on how to choose an identical loading factor for all eigenvalues, relatively few investigations on variable loading (VL) have been conducted. A low-complexity VL beamformer is proposed in which the beamformer weight vector is deliberately prevented from converging to the noise components. Then inspired by the traditional identical loading method, the loading factor can be set in an ad hoc manner. Numerical results demonstrate the superior performance of the proposed beamformer relative to other existing approaches such as ‘identical diagonal loading’ and ‘robust Capon’ beamformers.
- Author(s): M. Agarwal ; A.K. Behera ; M.K. Meshram
- Source: Electronics Letters, Volume 52, Issue 5, p. 340 –342
- DOI: 10.1049/el.2015.4134
- Type: Article
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Closed ring resonator (CRR)-based quad-band metamaterial absorber is presented. The unit cell of proposed absorber consists of four separate CRRs which are diagonally connected to square patches enclosed within an individual CRR. The structure is fabricated on 0.8 mm-thick FR4 substrate. Simulated peak absorptivities of 98.5, 97.7, 94.8, and 96% are obtained at 4.34, 6.68, 8.58, and 10.64 GHz, respectively. The measured and simulated absorption characteristics of the proposed absorber are in good agreement. The proposed absorber is wide angle and polarisation insensitive and has identical absorption characteristics for both transverse-electric and transverse-magnetic polarised radiations.
0.6-V 2.1-mW RF receiver based on passive mixing and master–slave common-mode rejection technique in 65 nm CMOS
Compact MIMO/diversity slot antenna for UWB applications with band-notched characteristic
Low-complexity variable loading for robust adaptive beamforming
Wide-angle quad-band polarisation-insensitive metamaterial absorber
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- Author(s): S. Kwon ; H. Lee ; S. Lee
- Source: Electronics Letters, Volume 52, Issue 5, p. 342 –344
- DOI: 10.1049/el.2015.3613
- Type: Article
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A time-domain microwave imaging system with improved image quality is presented for early detection of breast cancer. The time-domain system has the advantage of short scan time compared with the frequency-domain system but suffers from low signal-to-noise ratio (SNR) due to high attenuation of the RF signal within the breast tissue. Signal averaging of repeated measurements can improve the SNR, but this method also smears the signal peaks due to the signal-averaged jitter, which adversely affects the reconstructed image quality. An image enhancement method using Gaussian bandpass filtering (BPF) is proposed for a time-domain imaging system. The results from the proposed method were compared with those from the deconvolution method, which is typically used to remove the effects of signal-averaged timing jitter in short pulse measurements. Simulation results with a 3D hemispherical homogeneous breast model containing tumour cells revealed improvement of the reconstructed image quality with the proposed method in the presence of timing jitter. The signal-to-mean ratio was increased from 6.46 to 14.15 with BPF, whereas deconvolution resulted in an increase to 9.36. Simulation results with a non-homogeneous realistic breast model also showed image enhancement with the proposed method.
Image enhancement with Gaussian filtering in time-domain microwave imaging system for breast cancer detection
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- Author(s): Linfeng Wang ; Qiao Meng ; Wenwei He ; Daoyuan Zhang ; Hengfei Ma
- Source: Electronics Letters, Volume 52, Issue 5, p. 344 –346
- DOI: 10.1049/el.2015.3934
- Type: Article
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In high-speed folding and interpolating ADC design, an important issue is the encoding error result from the fine and coarse channel joint encoding technology. The last bit of the coarse channel only uses the last comparator of the fine channel to encode, the misjudgement of this comparator caused by offset and other non-ideal factors will lead to the encoding error of the last bit of the coarse channel and deteriorate the linearity. A digital encoding calibrated unit is presented. It utilises the lowest four comparators of the fine channel instead of one to calibrate error encoding of the comparator. An 8 bit 1 GS/s folding and interpolating ADC with this digital encoding calibrated unit is fabricated in 180 nm CMOS technology has been used to assess the validity of the calibration.
- Author(s): Bo Zhou ; Shuli Liu ; Patrick Chiang
- Source: Electronics Letters, Volume 52, Issue 5, p. 346 –348
- DOI: 10.1049/el.2015.2637
- Type: Article
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A near-threshold low-complexity bandgap reference (BGR) and power-on reset (POR) hybrid circuit is implemented in 65 nm CMOS, with an ultra-low supply voltage of 0.55 V and power consumption of 2.5 μW. The BGR employing amplifier offset voltage and current matching, and the POR based on offset voltage matching and loop settling feature, are proposed. The circuit-level simulation results verify that the presented implementation, not only generates a stable reference voltage with the typical temperature coefficient of 120 ppm/°C and line-regulation feature of 3.3%/V, but provides a robust reset signal with power-on and brown-out detection function. The proposed near-threshold circuit has ultra-low power supply and design complexity, both for BGR and POR modules, when compared to the reported.
- Author(s): Shiuh-hua Wood Chiang
- Source: Electronics Letters, Volume 52, Issue 5, p. 348 –350
- DOI: 10.1049/el.2015.3664
- Type: Article
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A ‘charge-dumping’ digital-to-analogue converter (DAC) switching scheme is proposed for successive-approximation-register analogue-to-digital converters. The proposed switching scheme utilises switched current sources to shift DAC voltages without consuming any power. The proposed scheme reduces DAC switching energy by 99.86% and DAC capacitance by 93.75% from the conventional scheme, the highest reductions among all reported switching schemes.
Digital encoding calibrated unit used in 8 bit 1 GS/s folding and interpolating ADC
Low-complexity 0.55-V 2.5-μW bandgap reference and power-on reset hybrid circuit
Charge-dumping switching scheme for successive-approximation-register analogue-to-digital converters
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- Author(s): M. Kim ; Hangil Joe ; Son-Ceol Yu
- Source: Electronics Letters, Volume 52, Issue 5, p. 350 –352
- DOI: 10.1049/el.2015.3809
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A dual-loop robust controller is proposed for precise position control of an autonomous underwater vehicle under uncertain hydrodynamics and unknown disturbances. In the inner-loop, a time-delay controller is presented in which a time-delay estimator estimates uncertain hydrodynamics and unknown disturbances from its time-delayed information and cancels these, thereby reducing control efforts on internal dynamics considerably. In the outer-loop, the linear controller stabilises the position error of the AUV without prior knowledge on values of hydrodynamic parameters. The proposed dual-loop controller features simple structure and easy implementation because it does not require real-time estimation of hydrodynamics.
Dual-loop robust controller design for autonomous underwater vehicle under unknown environmental disturbances
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- Author(s): P. Ransom ; Z. Larimore ; S. Jensen ; M.S. Mirotznik
- Source: Electronics Letters, Volume 52, Issue 5, p. 352 –354
- DOI: 10.1049/el.2015.3326
- Type: Article
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A method to fabricate continuously tapered antireflective (AR) coatings using fused deposition modelling (FDM) is presented. The method leverages FDM's ability to fabricate spatially varying 3D structures with variable polymer fill volumes, thus producing a spatially varying effective permittivity profile. The method is validated experimentally within the Ka-band. Experimental results closely match predictions, and AR treated samples demonstrate much less transmission loss than non-AR treated samples.
Fabrication of wideband antireflective coatings using fused deposition modelling
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- Author(s): K. Lee and J. Jeong
- Source: Electronics Letters, Volume 52, Issue 5, p. 354 –355
- DOI: 10.1049/el.2015.3612
- Type: Article
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A new bilateral frame rate up-conversion (FRUC) algorithm based on the bi-directional comparison of the texture complexity in the reference frame is proposed. In the proposed algorithm, the accuracy of the motion estimation (ME) process is determined by the comparison of the prediction size in the reference region of the bi-directional ME process. Base on this comparison, the adaptive refinement process is adjusted. In the experimental results, the proposed algorithm outperforms the conventional bilateral FRUC algorithm by 0.27 dB.
- Author(s): Sangseok Hong ; Jin S. Lee ; Tae-Yong Kuc
- Source: Electronics Letters, Volume 52, Issue 5, p. 355 –357
- DOI: 10.1049/el.2015.2500
- Type: Article
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An algorithm that can compute the rotation angle between two images is proposed, independently of the translation angle by using only two-point correspondence pairs. A parameterised solution vector can be calculated from the null-space of a matrix constructed of two-point correspondence pairs, and then the rotation angle is evaluated from this vector by using the relation between the elements of the essential matrix. Once the rotation angle is determined, the translation angle can be computed by using the Ackermann steering constraint, and then the translation distance can be determined. In the experiments, the proposed algorithm estimated the rotation angle and the translation distance better than did previous algorithms.
- Author(s): H. Ha and E.-S. Ryu
- Source: Electronics Letters, Volume 52, Issue 5, p. 357 –359
- DOI: 10.1049/el.2015.3093
- Type: Article
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A layer weight switching-based unequal Luby transform (LWS-ULT) method is proposed to minimise video distortion over packet-lossy networks. The proposed ULT method divides all quality layers into more important set (MIS) and less important set to provide unequal packet protection property in LT codes based on error propagation effects. The number of quality layer in MIS is adjusted in accordance with channel status. At high packet loss rate, lower number of quality layer is assigned into MIS for more protection of quality layer with larger error propagation weight. On the other hand, higher number of quality layer is included in MIS for improving video quality by expanding the range of protection at low packet loss rate. Simulation results demonstrate that the proposed LWS-ULT method gives robust performance and significantly improved video quality (0.9–1.2 dB in Y-PSNR), compared with the conventional ULT schemes.
- Author(s): H.W. Yu ; J.D. Jeon ; B.H. Lee
- Source: Electronics Letters, Volume 52, Issue 5, p. 359 –361
- DOI: 10.1049/el.2015.2599
- Type: Article
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A new smoothing algorithm to obtain surface normals for superpixels in the noisy depth image is proposed. For smoothing surface normals, the plane normal that indicates a surface characteristic is obtained by considering the inherent geometric similarity. This process results in smoothed surface normals which are free from noise of the depth image. The superpixels method with suggested smoothing algorithm outperforms in higher quality than the state-of-the art oversegmentation algorithms. The proposed technique can also be applied to any smoothing algorithms using surface normals for 3D features. Experimental results to demonstrate the effectiveness of the proposed smoothing surface normal technique is provided.
Bilateral frame rate up-conversion algorithm based on the comparison of texture complexity
Improved algorithm to estimate the rotation angle between two images by using the two-point correspondence pairs
Reliable scalable video streaming using layer weight switching-based unequal Luby transform
Surface normal smoothing for superpixels in noisy depth images
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- Author(s): E. Abolfazli and V. Shah-Mansouri
- Source: Electronics Letters, Volume 52, Issue 5, p. 361 –363
- DOI: 10.1049/el.2015.2818
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Transmission control protocols (TCPs) are used to control the congestion in the Internet. Various types of TCP protocols have been proposed including TCP Reno, TCP Tahoe and TCP Vegas. Although TCP Reno is widely used for wired communications, TCP Vegas is proved to have better performance in wireless environments. In TCP Reno, to achieve a certain queue level at the intermediate routers, active queue management (AQM) schemes are used. An AQM scheme marks the packets at the intermediate routers and TCP Reno source uses that mark to adjust its speed. However, in TCP Vegas, such scheme is not useable. Consequently, the queue level adjustment is not achievable. A scheme which is employed at the source and adjusts the TCP Vegas parameters dynamically to achieve a certain queue level at the intermediate router is proposed. To the best of the knowledge, this is the first attempt to dynamically adjust the queue levels when TCP Vegas is employed. Our proposed scheme plays the role of AQM in TCP Reno for TCP Vegas. The control scheme presented is designed based on integral backstepping technique and will be applied to the linearised model of TCP Vegas.
- Author(s): D.-S. Yoo and J. Lim
- Source: Electronics Letters, Volume 52, Issue 5, p. 363 –365
- DOI: 10.1049/el.2015.2188
- Type: Article
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An analytic mean squared error formula is derived for transform-based decision-directed channel estimation schemes in general M-ary phase shift keying modulated OFDM systems.
- Author(s): Qingshuang Zhang ; Aijun Liu ; Yingxian Zhang
- Source: Electronics Letters, Volume 52, Issue 5, p. 365 –367
- DOI: 10.1049/el.2015.3729
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Theoretically, the accurate signal-to-noise ratio (SNR) is necessary when using a successive cancelation (SC) or belief propagation (BP) decoder for polar codes. However, the effect of an SNR mismatch on the bit error rate performance of polar codes has not been addressed yet. The sensitivity of polar decoding with SC and BP decoders to the mismatch of SNR is studied. Theoretical and simulation results show that an estimation of SNR is not necessary for polar codes from a practical point of view.
- Author(s): Guohua Zhang
- Source: Electronics Letters, Volume 52, Issue 5, p. 367 –369
- DOI: 10.1049/el.2015.2634
- Type: Article
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From Sidon sequences, two explicit methods for constructing (2J, 2L)-regular type-II quasi-cyclic (QC) low-density parity-check (LDPC) codes are proposed without four cycles. The advantage of the new methods is two-fold: (i) compared with the existing lower bound of circulant permutation matrix (CPM) sizes above which type-II QC-LDPC codes exist without four cycles, the novel constructions enable much tighter lower bounds; and (ii) the codes constructed by the first method perform almost as well as type-II QC-LDPC codes from perfect cyclic difference set, while possessing a much more flexible CPM sizes.
Dynamic adjustment of queue levels in TCP Vegas-based networks
MSE expression for transform-based decision-directed channel estimation schemes in M-PSK OFDM systems
Signal-to-noise ratio mismatch in polar codes
Type-II quasi-cyclic low-density parity-check codes from Sidon sequences
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- Author(s): M. Varonen ; A. Safaripour ; D. Parveg ; P. Kangaslahti ; T. Gaier ; A. Hajimiri
- Source: Electronics Letters, Volume 52, Issue 5, p. 369 –371
- DOI: 10.1049/el.2015.3337
- Type: Article
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The feasibility of using CMOS technology for RF amplification in atmospheric remote sensing receiver is studied. The design and measurement results of a 200-GHz low-noise amplifier which is fabricated using a 32-nm SOI CMOS technology are presented. The 8-stage amplifier in a common-source configuration achieves a 9-dB noise figure and 25-dB gain with a power consumption of 33 mW.
- Author(s): Sen Wang and Ren-Hua Chang
- Source: Electronics Letters, Volume 52, Issue 5, p. 371 –372
- DOI: 10.1049/el.2015.3392
- Type: Article
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A bandpasss filter (BPF) using active transmission lines (ATLs) in a standard 0.18 μm CMOS technology at the 2.4 GHz band is presented. The ATL consists of a passive transmission line which is loaded by Λ-type circuits periodically. The ATL incorporating the Λ-type circuits not only compensates its resistive losses but also increases the slow-wave factors. Moreover, an inductor is also used in the BPF to improve the passband flatness and circuit instability. Under a power consumption of 21 mW, the BPF achieves 0.5 dB insertion loss at the centre frequency of 2.3 GHz, and a 3 dB bandwidth of 550 MHz.
- Author(s): N. Janković ; G. Niarchos ; V. Crnojević-Bengin
- Source: Electronics Letters, Volume 52, Issue 5, p. 372 –374
- DOI: 10.1049/el.2015.4087
- Type: Article
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A novel UWB bandpass filter based on a grounded square patch resonator with slots is proposed. Owing to this specific geometry, three fundamental resonances of the resonator can be independently controlled and by their even distribution within the UWB range, an UWB passband can be formed. An UWB filter with in-band insertion loss <0.9 dB, group delay variation of 0.25 ns, and very small size of only 0.26λ g × 0.26λ g has been designed and fabricated, and measurement results are in good agreement with simulations.
- Author(s): S. Jain ; F. Ellinger ; N.T. Tchamov
- Source: Electronics Letters, Volume 52, Issue 5, p. 374 –376
- DOI: 10.1049/el.2015.3884
- Type: Article
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This Letter reports an active inductor digitally controlled oscillator (DCO) for fast switchable low power wireless wake-up receivers. The LO output is held low when the enable pin is high and it oscillates when the enable pin goes low. The MOS transistor is used to turn on the oscillator for 200 ns (T on) to mitigate the requirement of wake-up receivers (T cycle = 1 µs). To save the die area, a symmetric differential-pair active inductor topology with 4-bit capacitor bank is proposed. The implemented circuit has one tenth of the chip size of LC oscillator.
- Author(s): A.A. Gaskell and T. Stander
- Source: Electronics Letters, Volume 52, Issue 5, p. 376 –378
- DOI: 10.1049/el.2015.3417
- Type: Article
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An on-chip implementation of a W-band filter with dual notches at 82 and 95 GHz is presented. Reflection mode filtering methods are implemented with dual hairpin resonator networks, using the inherent parasitic losses in the resonators to create matched loads at the stopband frequencies of interest while reflecting passband power. Notches of 6 and 10.6 dB stopband insertion loss, and 3.7 and 5.6% relative bandwidths, respectively, were achieved. This represents the first implementation of reflection mode filtering in the W-band on-chip.
- Author(s): V.V. Komarov ; V.P. Meschanov ; N.F. Popova
- Source: Electronics Letters, Volume 52, Issue 5, p. 378 –379
- DOI: 10.1049/el.2015.4214
- Type: Article
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A compact millimetre-wave waveguide load with wedge-shaped dielectric inserts is considered. Its reflectivity is studied numerically and experimentally. Chosen absorber shape and sizes provide good matching over a wide-frequency range 37.5–53.57 GHz. Simulations are carried out for two options of waveguide sizes.
200-GHz CMOS amplifier with 9-dB noise figure for atmospheric remote sensing
2.4 GHz CMOS bandpass filter using active transmission line
Compact UWB bandpass filter based on grounded square patch resonator
Fast sampling DCO for 2.4 GHz wake-up receiver
Reflection mode mm-wave on-chip notch filters using coupled hairpin resonators
Short waveguide load for millimetre-wave applications
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- Author(s): M.N. Hutchinson ; K.E. Thompson ; N.J. Frigo
- Source: Electronics Letters, Volume 52, Issue 5, p. 379 –381
- DOI: 10.1049/el.2015.3090
- Type: Article
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A link employing a polarisation modulator aligned for intensity modulation applications is presented in which a discrete source of polarisation-dependent loss (PDL) is mitigated by intentionally altering the bias phase point of the link. The experimental data is verified by an earlier theoretical approach which describes a discrete PDL impairment in an otherwise ideal RF photonic link. The cancellation technique provided as much as 20 dB suppression of second-order distortion in the link.
Suppression technique for discrete polarisation-dependent loss in a polarisation modulated link
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- Author(s): Yancheng Ma ; Liang Fang ; Guoan Wu
- Source: Electronics Letters, Volume 52, Issue 5, p. 381 –383
- DOI: 10.1049/el.2015.4061
- Type: Article
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Helical gratings (HGs) have an achievement of flexible mode conversion for fibre-guided orbital angular momentum (OAM) modes. Sampled reflection HGs can realise the generation and conversion of OAM mode with comb spectra. They can be used to simultaneously filter wavelengths and convert modes, and thus may be applied to the hybrid multiplexing technology with wavelength division multiplexing and mode-division multiplexing.
- Author(s): A.A. Andronov ; E.P. Dodin ; Yu.N. Nozdrin ; V.I. Pozdnyakova ; Yu.G. Sadofiev ; A.G. Fefelov
- Source: Electronics Letters, Volume 52, Issue 5, p. 383 –385
- DOI: 10.1049/el.2015.4033
- Type: Article
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Properties of disk cavities for terahertz (THz) heterostructure lasers are discussed basing on observation of emission and beam from THz quantum cascade disk laser and analytical evaluation of modes, beams and losses of the laser disk cavities. The measured laser beam has beam peak at about 30° from vertical. To find condition for vertically emitted beam and for evaluation of the laser modes, emission beams and losses simple approach adopted in theory of slit (patch) antennas is used. With this approach results on observed laser beam are discussed and a possibility to create single-frequency disk laser with narrow vertical beam. This can be achieved if only single TEM1m cavity mode is exited. Several examples of such possibility for 100 µm wavelength with disk cavities from 18 to 200 µm in diameter and with cascade thickness 10 µm are presented. Depending on the diameter the cavity emission losses are higher than or of about that of THz quantum cascade laser waveguide losses or amplification. For wavelength longer than 100 µm and (or) with lower cascade thickness, the losses go down and cavity could be optimised for creation a single-mode powerful vertically emitted disk laser.
- Author(s): S. Butera ; P. Vines ; C.H. Tan ; I. Sandall ; G.S. Buller
- Source: Electronics Letters, Volume 52, Issue 5, p. 385 –386
- DOI: 10.1049/el.2015.3995
- Type: Article
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Time-of-flight measurements using pulsed laser illumination in the wavelength region between 1.3 to 2.37 μm have been demonstrated with an InAs avalanche photodiode (APD). InAs is photo-sensitive at wavelengths up to 3.5 μm and with predominantly electron multiplication reducing detector noise, InAs APDs have clear potential for sensitive optical measurements of picosecond transients in the mid-wave infrared. Laboratory-based demonstrations of time-of-flight ranging using InAs APDs operated at room temperature is described.
Comb mode converters based on sampled helical gratings
Modes, emission beams and losses of THz heterostructure disk lasers: single-mode laser with vertical beam option
Picosecond laser ranging at wavelengths up to 2.4 μm using an InAs avalanche photodiode
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- Author(s): L. Fan ; P.B. Monk ; A. Lakhtakia
- Source: Electronics Letters, Volume 52, Issue 5, p. 387 –388
- DOI: 10.1049/el.2015.3564
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If solar radiation can split into beams diffracted in different directions depending on the wavelength of the light, solar energy may be harvested efficiently using different photovoltaic solar cells optimised for different spectral regimes. Simulations based on the solution of the Maxwell equations lead to an optimal blazed-grating spectrum splitter.
- Author(s): M. Laour and R. Tahmi
- Source: Electronics Letters, Volume 52, Issue 5, p. 388 –390
- DOI: 10.1049/el.2015.3296
- Type: Article
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An effective solution is introduced aimed to reduce the size and cost of electromagnetic interference (EMI) filters in dc–dc converters. This method is based on the insertion of small ground inductor (grounded through RF inductor). This technique is suitable for unshielded cables. The RF inductor prevent the return current of the common-mode (CM) noise at high frequencies, it is inserted between the earth ground (ground reference plane) and the chassis ground of the converter, therefore it isolate the converter chassis from power line ground at high frequencies. As well, maintaining the electrical safety grounding at the power frequency with very low impedance to ground. The efficiency of the proposed method is demonstrated by combining measurements and simulations for the fast testing. The level of CM current is compared versus a specific standard. This allows showing that the EMI emission levels can be reduced by as much as 30 dB.
- Author(s): Bo Yang ; Xiao Yu Peng ; Wen Feng Zheng ; Shan Liu
- Source: Electronics Letters, Volume 52, Issue 5, p. 390 –392
- DOI: 10.1049/el.2015.3779
- Type: Article
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A new algorithm for online power system frequency estimation is presented. The discrete power signal is decomposed into two subband signals by using a pair of orthogonal FIR filters. The frequency in each subband is measured quickly with three consecutive samples. Optimal estimation is achieved by fusing the measurements from the subbands based on a simple noise model. The effectiveness of the proposed algorithm is verified on simulated signals.
- Author(s): Eonsu Noh ; Kwang Hee Ko ; Kangwook Kim
- Source: Electronics Letters, Volume 52, Issue 5, p. 392 –393
- DOI: 10.1049/el.2015.3820
- Type: Article
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A transmitter (Tx) coil system without ferrite was designed and fabricated for use in wireless power transfer (WPT) based on magnetic induction. The Tx coil system consists of an active coil, which is directly connected to the source, and a parasitic coil, which replaces the ferrite. The effects of the parasitic coil parameters, i.e. size, number of turns, and distance from the active coil, on the WPT performance were investigated in terms of the utility value, which was developed based on the power transmission efficiency and shielding effectiveness. The proposed Tx coil system was fabricated, and its performance was measured. The measured results show that the proposed Tx coil system performs better than a conventional Tx coil in terms of the utility value.
Blazed-grating spectrum splitter for harvesting solar energy
Effective filtering solution with low cost small size for common-mode reduction in dc–dc converters
Optimal orthogonal subband fusion for online power system frequency estimation
Transmitter coil system without ferrite in wireless power transfer
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- Author(s): Da Lu and Bin Zou
- Source: Electronics Letters, Volume 52, Issue 5, p. 393 –395
- DOI: 10.1049/el.2015.3268
- Type: Article
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Land cover classification is one of the primary applications of remote sensing. Polarimetric synthetic aperture radar provides significant information of scattering mechanism for classification. The alpha angle extracted from the Cloude eigenvector decomposition has been wildly used in discriminating targets. However, the alpha angle is always overestimated in forest area, which will induce misclassification. The estimation bias of alpha angle will be discussed. An improved alpha angle estimation method is introduced to overcome the aforementioned problem. A validation process is performed by using National Aeronautics and Space Administration/Jet Propulsion Laboratory Airborne Synthetic Aperture Radar data.
Improved alpha angle estimation of polarimetric SAR data
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- Author(s): M.J. Hagmann and T.E. Henage
- Source: Electronics Letters, Volume 52, Issue 5, p. 395 –397
- DOI: 10.1049/el.2015.3671
- Type: Article
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A simplified method for calculations of the current in a tunnelling junction with its orientation and spatial distribution is described. The current at test points on either electrode is calculated for the shortest distance with expressions for point-to-point tunnelling by Simmons (1963) and then summed. The calculated distribution of the current in a spherical-tip/planar-sample model of a scanning tunnelling microscope (STM) agrees with that from finite-element simulations. This method may be applied to models having arbitrary shapes, and results are presented for a paraboloidal-tip/corrugated-sample STM model as the first approximation to the atomic structure.
Simplified calculations of the lateral distribution for the current in tunnelling junctions having general shapes
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- Author(s): V.R. Krstić
- Source: Electronics Letters, Volume 52, Issue 5, p. 397 –399
- DOI: 10.1049/el.2015.3052
- Type: Article
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The stochastic gradient algorithm presented employs the time-varying neuron's slope to optimise performing of the all-pole filter-whitener maximising the joint Shannon's entropy. By using the time adaptive slope, which matches the unknown probability density function of an input process, a neuron slope selection issue of the original algorithm is facilitated and its tracking of non-stationary statistics is improved. The performing of algorithm is verified using the whitener as a front-end amplitude equaliser of the blind equaliser.
- Author(s): Wenzhen Yue ; Yan Zhang ; Jingwen Xie
- Source: Electronics Letters, Volume 52, Issue 5, p. 399 –401
- DOI: 10.1049/el.2015.3963
- Type: Article
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A simple and effective quadrature phase shift keying (QPSK) signal design for a given correlation matrix is presented. The method exploits the correlation properties generated by memoryless nonlinear transformation of a Gaussian process. The correlation matrix of the designed QPSK signal is compared to the given matrix and good approximation is achieved.
Entropy-based stochastic gradient algorithm with adaptive neuron slope for all-pole whitening
QPSK signal design for given correlation matrix
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- Author(s): Yonghong Zhao ; Linrang Zhang ; Yabin Gu
- Source: Electronics Letters, Volume 52, Issue 5, p. 401 –402
- DOI: 10.1049/el.2015.2931
- Type: Article
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An off-grid direction-of-arrival (DOA) estimation method using sparse Bayesian learning (SBL) based on an array covariance matrix is presented. By the vectorisation operator, a new off-grid model that has a wider aperture and can therefore detect an increased number of sources is built. A scheme of SBL is utilised to estimate off-grid DOAs without needing to know the number of sources. Owing to the extended aperture and off-grid model, the proposed method cannot only improve the angle resolution but also enhance the accuracy of DOA estimation. Simulation results demonstrate the efficiency of the proposed method and illustrate the performance improvement over the existing methods.
- Author(s): B. Ozbek
- Source: Electronics Letters, Volume 52, Issue 5, p. 403 –404
- DOI: 10.1049/el.2015.2919
- Type: Article
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Device-relaying enhanced multiple-input single-output (MISO) orthogonal frequency-division multiple access (OFDMA) systems are one of the promising and cost-effective methods to satisfy data rate requirements of future wireless networks. To implement device relaying in MISO-OFDMA systems efficiently, the channel state information belonging to all links is required at the base station. However, the feedback load increases with the number of users, device-relay candidates, antennas and subcarriers. A novel scheduling and a joint feedback link design and relay selection algorithm in device-relaying enhanced downlink MISO-OFDMA systems are proposed, while reducing the feedback load significantly without sacrificing the system performance.
- Author(s): Yongle Wu ; Lidan Yao ; Lingxiao Jiao ; Weimin Wang ; Yuanan Liu
- Source: Electronics Letters, Volume 52, Issue 5, p. 405 –406
- DOI: 10.1049/el.2015.4131
- Type: Article
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A novel UWB balun with complete ground based on vertically mounted planar structure is presented. Two mutually perpendicular planes comprise the proposed balun. The vertical configuration of double-sided parallel-strip line ensures complete ground in the horizontal plane and the cascading of seven-section quarter-wavelength transformers facilitates UWB functionality. For verification, a prototype balun is designed, fabricated and measured. The simulation and measurement agree well, exhibiting a bandwidth from 0 up to 8 GHz with good return loss, flat insertion losses and high stability of 180° phase difference.
Array covariance matrix-based sparse Bayesian learning for off-grid direction-of-arrival estimation
Reduced feedback link design for device-relaying enhanced multiple-input single-output orthogonal frequency-division multiple access wireless systems
UWB balun with complete ground based on vertically mounted planar structure
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- Source: Electronics Letters, Volume 52, Issue 5, p. 406 –407
- DOI: 10.1049/el.2015.4276
- Type: Article
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Erratum: ‘Fully integrated CMOS overvoltage protection circuit for automotive applications’
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