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Electronics Letters

Issue 5 • Date February 28 2013

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Displaying Results 1 - 25 of 41
  • In brief

    Page(s): 310
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  • Interview

    Page(s): 310
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    Dr. Oscar Gustafsson from Linkoping University in Sweden talks about the research behind his paper 'Unified architecture for 2, 3, 4, 5, and 7-point DFTs based on the Winograd Fourier transform algorithm' on page 348. View full abstract»

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  • Phase space

    Page(s): 311
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    Researchers at the University of Cantabria in Spain have designed and fabricated a phase switch for use in radio astronomy and other microwave measurement systems. Using existing techniques and an unconventional application of bandpass filters the group have created a phase switch that can be integrated into a microwave receiver, optimise imbalances between branches and reduce noise. View full abstract»

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  • Aiming for the sky

    Page(s): 312
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    Research from France presents a compact, single-source subwavelength metamaterial directive Fabry-Pérot cavity antenna with 56° of beam steering aimed at aerospace applications. View full abstract»

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  • Metamaterial-based frequency reconfigurable antenna

    Page(s): 315 - 316
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    A frequency reconfigurable antenna based on metamaterial is presented. It is composed of a coplanar-fed straight-line monopole with two double split-ring resonators (DSRRs) of different size disposed at its proximity. Each cell exhibits a negative permeability over a frequency band, which produces magnetic couplings with the monopole that starts to radiate at new bands; the whole structure is now a tri-band antenna. The frequencies over which the two DSRRs exhibit a negative permeability have been arbitrarily chosen to show that the proposed approach can be used to create new operating bands and also to introduce notches. By using a single switch at each metamaterial cell, their effect can be deactivated and the corresponding resonance can be suppressed, resulting in a frequency reconfigurable antenna. Simulated and measured results are presented and good agreement is achieved. View full abstract»

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  • Broadband beam scanning circularly-polarised leaky-wave antenna based on modified substrate integrated waveguide

    Page(s): 316 - 318
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (482 KB)  

    A high gain broadband beam scanning circularly-polarised (CP) leakywave antenna (LWA) is proposed based on a modified substrate integrated waveguide. The designed CP LWA has been fabricated and its performance measured. The reported antenna presents expected broadband matched impedance with a measured reflection coefficient |S11| <;- 10 dB from 15.4 to 19 GHz. The radiation pattern was measured and the axial ratio of the antenna is within 3 dB from 15.9 to 17.2 GHz. The antenna exhibits continuous beam scanning from 35° at 15.5 GHz to 47° at 18 GHz according to the broadside with maximum gain of 12.3 dBi. View full abstract»

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  • Fast measurement of antenna pattern overlap matrix in reverberation chamber

    Page(s): 318 - 319
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (215 KB)  

    Presented is a fast way for the measurement of the pattern overlap matrix in an arbitrary multi-port antenna system by a reverberation chamber. This parameter is central for calculation of the spatial correlation between different elements with arbitrary terminations. To the authors' knowledge, this is the fastest method for the measurement of the pattern overlap matrix in a lossy structure. View full abstract»

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  • Inductive-varying grid for highly beamsteerable cavity antennas

    Page(s): 319 - 321
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (369 KB)  

    The design of a locally one-dimensional inductive-varying metamaterial operating near 10 GHz is reported. This is combined with a fixed capacitive grid to design a phase-varying metasurface. This composite metasurface is then used as a partially reflecting surface (PRS) together with a perfect electric conductor surface to form a resonant Fabry-Pérot type cavity. A patch antenna acting as a primary source is embedded in the cavity to constitute a highly beam-steerable directive antenna. A 56́ deflection of the antenna beam is experimentally observed. View full abstract»

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  • Wideband and non-dispersive wavelet transmission using leaky lens antenna

    Page(s): 321 - 322
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (405 KB)  

    An ultra-wideband, non-dispersive leaky lens antenna system for impulse applications has been designed, fabricated and characterised. An in-house wavelet generator is connected to the antenna to transmit 100 ps-long square pulses with centre frequencies at 45, 60 and 75 GHz. It is shown that the leaky lens antenna has negligible distortion and preserves the pulse shape generated by the millimetre-wave pulse generator. View full abstract»

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  • Innovative design of implanted medical lead to reduce MRI-induced scattered electric fields

    Page(s): 323 - 324
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (213 KB)  

    The radio frequency coils in magnetic resonance imaging (MRI) systems induce scattered electric fields in the implanted medical lead and result in tissue heating. A novel structure of the medical lead has been designed to reduce the scattered field. Proposed metal nails are placed along the medical lead. The scattered electric field is calculated near the medical lead tip at 64 MHz (1.5 T MRI). By installing this design on the conventional lead, a significant decrease in the scattered electric field at the tip of the lead is observed. View full abstract»

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  • Noise reduction in magnetic resonance images using adaptive non-local means filtering

    Page(s): 324 - 326
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    Proposed is a noise reduction method for magnetic resonance (MR) images. This method can be considered a new adaptive non-local means filtering technique since different weights based on the edgeness of an image are applied. Unlike conventional noise reduction methods, which typically fail in preserving detailed information, the proposed method preserves fine structures while significantly reducing noise in MR images. For comparing the proposed method with other noise reduction methods, both a simulated ground truth data set and real MR images were used. The experiment shows that the proposed method outperforms conventional methods in terms of both restoration accuracy and quality. View full abstract»

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  • 2-4 GHz wideband power amplifier with ultra-flat gain and high PAE

    Page(s): 326 - 327
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (401 KB)  

    Demonstrated is a 2-4 GHz wideband power amplifier (WPA) using Cree 10 W GaN HEMT CGH40010. Also a novel process to find the optimum impedances is presented, with which the gain flatness can be taken into account. A compact PCB has been fabricated and tested with continuous waves at low (20 dBm) and high (28 dBm) input power level. From the measured results, at low power level, the gain is 13.1-14.1 dB across 2.0-3.9 GHz and 12.3-14.1 dB across 2.0-4.0 GHz. For large signals, power gain is 11.1-12.6 dB with power-added efficiency (PAE) 36.5-53.4% while output power is around 40 dBm. Gain flatness keeps less than 1 dB beyond 95% of the band. For a 5 MHz WCDMA signal, the adjacent channel leakage ratio of the WPA with digital predistortion reaches - 45.3 dBc with an average drain efficiency of 46.7%. View full abstract»

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  • VCM-based monotonic capacitor switching scheme for SAR ADC

    Page(s): 327 - 329
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (198 KB)  

    A novel energy-efficient VCM-based monotonic capacitor switching scheme for successive approximation register (SAR) analogue to-digital converters (ADCs) is proposed. Based on the third reference voltage VCM and monotonic capacitor switching procedure, the proposed switching scheme achieves 97.66% less switching energy and 75% less number of capacitors over the conventional architecture, resulting in the most energy-efficient switching scheme among the reported switching sequences. View full abstract»

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  • Ternary R2R DAC design for improved energy efficiency

    Page(s): 329 - 330
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    An R2R DAC using three digital input levels rather than two is proposed as well as a modified two-level structure that emulates the three-level DAC's benefits. This three-level structure provides power reductions of 79% and linearity improvements due to matching of a factor of 2 over the two-level case. Ideal implementation is also described in terms of the logic needed to code the DAC and the requirements of the additional third reference level. View full abstract»

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  • Energy-efficient charge-recovery switching scheme for dual-capacitive arrays SAR ADC

    Page(s): 330 - 332
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (223 KB)  

    Proposed is an energy-efficient charge-recovery switching scheme for a dual-capacitive arrays successive approximation register (DCA-SAR) analogue-to-digital converter (ADC). With the use of the charge-recovery technique in a fully differential DCA-SAR architecture, the proposed switching scheme achieves 98.7 and 46.9% reduction in switching energy and area, respectively, while maintaining the switching energy constant for different output codes. View full abstract»

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  • FPGA realisation of inverse kinematics for biped robot based on CORDIC

    Page(s): 332 - 334
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (533 KB)  

    A FPGA realisation structure based on CORDIC is proposed to implement inverse kinematics for a biped robot. First, the angle equations of inverse kinematics for the biped robot are described. Based on these equations represented by the inverse tangent function, a FPGA structure based on two CORDIC operators of circular vectoring and hyperbolic vectoring is proposed and implemented on a FPGA chip. Finally, comparison of the proposed FPGA realisation and the software realisation to calculate these angle equations is presented to illustrate the effectiveness of the proposed structure. View full abstract»

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  • Generalised Pareto distribution for extreme value modelling in electromagnetic compatibility

    Page(s): 334 - 335
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (309 KB)  

    Statistical studies involved in risk management mainly focus on general tendencies which are considered as sufficient for non-critical applications. This implies laying aside extreme events which may nonetheless be crucial to the security of critical facilities. In light of this observation, it is proposed here to follow the opposite approach and to focus on the extreme values statistics. In particular, it is argued that the approach highlights the benefit of the extremal types theorem from the electromagnetic compatibility point of view. View full abstract»

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  • Fundamental relationship between bilateral Kernel and locally adaptive regression Kernel

    Page(s): 335 - 337
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    The relationship between the bilateral kernel function and the recently proposed locally adaptive regression kernel is examined. Despite the difference in implementation, both locally adaptive approaches are designed to prevent averaging across edges while smoothing an image. Their similarity suggests that they can reasonably be linked although both filtering approaches have grown to become well-established theories in their fields. First, the locally adaptive regression kernel is analysed theoretically. Then, the connection between the methods is explored by applying the spectral distance measure to the bilateral kernel. Finally, a direct relation is established between the bilateral kernel and the locally adaptive regression kernel. View full abstract»

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  • Object tracking using random sparse appearance model

    Page(s): 337 - 338
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (283 KB)  

    Selection of reliable templates is important for robust tracking. To this end a novel appearance model is proposed. This model consists of several representive templates. Each template, whose feature vector is extracted from a group of randomly selected feature points on the object, represents a different view of the object. By means of a sparse representation method, the appearance model is updated according to the sparse coefficients of the best candidate by solving l1-minimisation. Experiments with both public and the authors own challenging datasets show that the new method outperforms several state-of-the-art methods in accuracy. View full abstract»

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  • Optical road-ice detector operating in the near infrared

    Page(s): 338 - 340
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (361 KB)  

    Introduced is an optical approach for the assessment of the road conditions due to various atmospheric perturbations, such as the presence of ice and rain. The technique is based on measuring the polarisation contrast in reflection, in conjunction with the intensity of the diffused light, in the near infrared. View full abstract»

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  • Real-time swimmers' feedback based on smart infrared (SSIR) optical wireless sensor

    Page(s): 340 - 341
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (253 KB)  

    An IrDA link based on a serial infrared transceiver has been designed and implemented for real-time swimmers' feedback. A wrist-mounted accelerometer provided stroke information to the transmitter. The signal was detected using a photodiode detector. Both the transmitter and receiver units measured 27 ' 19 mm. Propagation experiments in air and under water were performed in a glass tank (91 ' 39 ' 45 cm) to validate the system. The maximum link length in air was 2 m and in still water 70 cm. In water with bubbles, the range reduced to 50 cm. This distance is sufficient for wrist'head communications during swimming. The information transmitted was the time duration of one complete stroke, which was updated every stroke and presented to the swimmer using an RGB LED mounted on the goggles. The hardware, software and implementation methods for the IrDA system are described. View full abstract»

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  • Spatiotemporal 3D motion vector filtering method for robust visual odometry

    Page(s): 341 - 343
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (393 KB)  

    Most of the previous visual odometry methods cannot deal with a large independently moving object that takes up over 50% of the image area. To overcome this problem, the spatiotemporal filter is incorporated into the RANSAC method to filter out false match that occurrs by a large independently moving object. This spatiotemporal filter uses the current and previous motion vector%s length and direction. Experimental results demonstrate that the proposed method effectively rejects the motion vectors generated from large independently moving objects and improves the visual odometry accuracy. View full abstract»

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  • Iterative Wiener filter

    Page(s): 343 - 344
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (154 KB)  

    A new adaptive filter algorithm, the iterative Wiener filter (IWF), is proposed to overcome the drawback of slow convergence speed for most LMS-type algorithms. The adaptive filter is posed as a problem of finding the solution of a linear matrix equation, equivalent to the Wiener equation. Then the step size is optimised, which is time variant in terms of the residual error in each step. This property gives the IWF the ability of fast convergent speed. The stability of the algorithm can be secured when the estimation of covariance and cross-covariance statistics become stationary. Only the product of the matrix and vector is needed for the implementation in each iteration. Numerical results demonstrate the superior performance of the IWF over some other LMS-type algorithms. View full abstract»

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  • Performance analysis for mobile-relay-based M2M two-way AF relaying in N*Nakagami-m fading

    Page(s): 344 - 346
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (163 KB)  

    The system outage probability of a mobile-relay-based two-way amplify-and-forward (AF) relaying system is investigated. Independently but not necessarily identically distributed N*Nakagami-m fading is adopted to provide a realistic description of the mobile-to-mobile (M2M) channel. By slightly adjusting the integral region, concise and generalised closed-form lower and upper bounds are obtained, providing valuable insight into practical system designs. Simulation results highlight the derived expressions and show that the lower bound can act as a tight closed-form outage probability expression. View full abstract»

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  • Polar codes for distributed source coding

    Page(s): 346 - 348
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (138 KB)  

    A polar coding method to construct a distributed source coding scheme which can achieve any point on the dominant face of the Slepian-Wolf rate region for sources with uniform marginals is proposed. Source encoding and decoding operations are performed using efficient algorithms which makes practical implementation feasible. Simulation results are given to exhibit the performance of the presented method. View full abstract»

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Aims & Scope

Electronics Letters is internationally renowned for its rapid communication of new developments and emerging topics across the broad and interdisciplinary field of modern electronics and electrical engineering.

Full Aims & Scope

Meet Our Editors

Editors-in-Chief

Professor Chris Toumazou
Director of the Biomedical Institute
Imperial College, London, UK

Professor Ian White
Head of Photonics Research
University of Cambridge, UK