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Electronics Letters

Issue 23 • Date November 11 2010

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Displaying Results 1 - 25 of 32
  • In brief

    Page(s): 1528
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (131 KB)  

    First Page of the Article
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  • Interview

    Page(s): 1528
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (67 KB)  

    "The aircraft industry is increasingly subject to economical as well as safety requirements" View full abstract»

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  • A rocking tune

    Page(s): 1529
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (149 KB)  

    A hybrid technology, which combines silicon MEMS and superconductor thin films, shows promise for tunable high-performance microwave circuits. Doped silicon has potential as a good low-loss dielectric material at cryogenic temperatures for device applications in frequency tuning and reconfiguration, UK-based researchers have shown. A team from the University of Birmingham demonstrated how their micromachined silicon rocking actuator can be used to tune a high temperature superconducting resonator without significantly affecting its Q factor. View full abstract»

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  • An opening for solar cells

    Page(s): 1530
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    In this paper, a cheap and efficient method for the manufacture of large-area selective emitter solar cells using laser processing as a photolithography step has been demonstrated. View full abstract»

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  • Compact CPW-fed ultra-wideband antenna with band-notched characteristic

    Page(s): 1533 - 1534
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (378 KB)  

    A CPW-fed ultra-wideband antenna with a band-notch characteristic is presented. By cutting two inverted L-shaped slots in the CPW ground, the impedance bandwidth of the proposed antenna can be enhanced. In addition, a tuning stub is inserted in the middle of the fork-like patch to achieve the band rejection characteristic. Experimental and numerical results show that the proposed antenna, with compact size of 21 × 28 mm, has an impedance bandwidth range from 2.38 to 10.6 GHz for a voltage standing-wave ratio less than 2, while rejecting the 5-6 GHz band. View full abstract»

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  • Compact wideband antenna with double-fed structure having band-notched characteristics

    Page(s): 1534 - 1536
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (339 KB)  

    A compact ultra-wideband (UWB) printed planar antenna with double band-notched characteristic is presented. This antenna consists of a circular monopole and two W-shaped slots etched into the monopole and the truncated ground plane, which lead to the desired high attenuation at the two notch frequencies: WiMAX (3.4-3.8 GHz), WLAN (4.8-6.2 GHz). It is fed by a microstrip line with a double-fed structure and built on an FR-4 substrate with 20 × 30 mm surface area. The antenna is successfully simulated by CST, and measured to cover the bandwidth for UWB (3.0-10.8 GHz), which is obtained with promising performances, including stable radiation patterns and constant gain over its whole frequency band of interest. View full abstract»

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  • Design of symmetric beam pattern reconfigurable antenna

    Page(s): 1536 - 1537
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    A radiation pattern-reconfigurable antenna is designed to operate over DCS 1800 and PCS 1900 bands. The proposed antenna is symmetric with respect to the vertical centre line and has a pair of pin diodes for switching. The electrical shape of the antenna consists of a monopole-loaded loop and an open wire, which serves as a director. Depending on the switching state, the antenna can select between two beam directions with essentially no input impedance variation. The return losses and radiation patterns for two bias conditions are measured and compared with simulated results. The measured results indicate that the antenna has high front-to-back ratios for both bias conditions, representing clear pattern reconfigurability. View full abstract»

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  • Dielectric-based leaky-wave antenna for high gain using a printed surface-wave source

    Page(s): 1537 - 1539
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (261 KB)  

    A multilayer leaky-wave antenna (LWA) is presented for microwave and millimetre-wave frequencies. By placing two superstrate dielectric layers on top of a base grounded dielectric slab, a practical resonant cavity structure can be realised for high gain at 17.39 GHz. The compact 6 × 6 cm LWA is fed by a printed surface-wave source integrated in the bottom ground plane. Measured gain values are greater than 11 dBi at broadside with half power beam less than 77°. The presented low cost and low profile LWA may be useful for radar applications and surveillance systems where lightweight and compact antenna designs are of interest. View full abstract»

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  • Isolation enhancement of planar disc antenna and ground plane in UWB applications

    Page(s): 1539 - 1541
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    A technique is proposed to mitigate the unwanted effect of ground plane currents when an antenna is mounted on a printed circuit board (PCB). To demonstrate the concept a CPW fed monopole is integrated onto a relatively large PCB. In the first stage of integration, a microstrip to grounded CPW feedline is incorporated to avoid connecting the PCB and antenna ground directly. To reduce the flow of current onto the edges of the PCB, two pairs of quarter-wavelength stubs are then utilised. A prototype is manufactured and examined. To show how this method enhances the radiation characteristics, the radiation patterns of the antenna in both an isolated and an integrated scenario with and without stubs are compared. View full abstract»

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  • Substrate integrated waveguide Yagi-Uda antenna

    Page(s): 1541 - 1542
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    A novel substrate integrated waveguide (SIW) Yagi-Uda antenna for 60 GHz applications is presented. The proposed antenna has the merits of low profile and light weight and is suitable for direct integration with the SIW wireless front end. Simulated results are compared with measured data and good agreement is reported. View full abstract»

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  • Wideband conical monopole antenna with frequency band-notched behaviour

    Page(s): 1542 - 1543
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    Wideband antennas with band-notched behaviour have recently attracted increasing interest. Presented is a conical monopole antenna with two C-shaped slots. Compared to previous work reported in the literature, the antenna provides a notch band with increased gain suppression within the notch band, combined with omnidirectional pattern at frequencies throughout the operating band. View full abstract»

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  • Non-uniform time sampling FIR filter design based on least-squares criterion

    Page(s): 1544 - 1545
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    The finite impulse response (FIR) digital filter for non-uniform time samples is investigated. By the upsampling technique this filter design is reduced to determining filter coefficients with many zeros. Only those coefficients that are not zeros correspond to time samples which are used to obtain the filtered output. Determining such a set of filter coefficients is exactly a best m-term approximation problem. The optimal non-uniform least-squares filter is obtained by a matching pursuit algorithm. In general, nonzero filter coefficients are not distributed consecutively in order to ensure the better performance of a filter. Satisfactory performances of the present method have been demonstrated by simulation. View full abstract»

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  • Small-area, periodically-refreshed DAC array in 45 nm SOI CMOS

    Page(s): 1545 - 1546
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (302 KB)  

    A small-area digital-to-analogue converter (DAC) in 45 nm SOI CMOS technology is presented that is based on a centrally located, static current-mode DAC, the output current of which is fed to an array of distributed, dynamically-refreshed small-area DACs. Owing to the dynamic operation of the distributed DACs, a single array element can be made as small as 8 × 8 μm. The measured retention time of a single array element with 7-bit resolution is 3 ms at a temperature of 125°C. View full abstract»

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  • Adaptive sharpening of depth maps for 3D-TV

    Page(s): 1546 - 1548
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (199 KB)  

    Depth maps, which can be represented as greyscale images, are used to aid rendering of novel views in three-dimensional (3D) video systems. However, compressing them using existing video codecs, such as H.264/AVC, leads to low quality rendered views. Presented is a sharpening method based on adaptive bilateral filtering to eliminate certain artifacts observed in compressed depth maps to improve the quality of rendered views. Experimental results demonstrate that significant rendering quality improvements of up to 1.9 dB can be achieved with the proposed method. View full abstract»

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  • Compressed sensing joint reconstruction for multi-view images

    Page(s): 1548 - 1550
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    The problem of compressed sensing joint reconstruction of multi-view images in camera networks is considered. Noting that the neighbouring images are visually similar, the multi-view correlation is captured by the sparse prior of the difference images between two contiguous multi-view images. Thus the joint reconstruction is formulated as an unconstrained optimisation problem, which contains a quadratic fidelity term and two regularisation terms encouraging the sparse priors for multi-view images and their difference images, respectively. Moreover, an effective iterative algorithm is presented to solve the optimisation problem. Experimental results with the real multi-view images show that the proposed method can perform joint reconstruction with greater accuracy than CS image-by-image reconstruction. View full abstract»

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  • Interactions of an eddy current sensor and a multilayered structure

    Page(s): 1550 - 1551
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (234 KB)  

    A study of the interactions between a cup-core eddy current sensor and a metallic layered structure is reported. An affine relationship between the sensor's normalised impedance and the distance between two plates of a metallic assembly is brought to light both by the experiment and by finite elements computations. View full abstract»

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  • ΔΣ digitised polar transmitter with CMOS switching power amplifier

    Page(s): 1551 - 1553
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    A delta-sigma (ΔΣ) digitised polar RF transmitter with a CMOS switching power amplifier is presented. The proposed power amplifier consists of a class-E amplifier with a modulating current source which allows high efficiency and high linearity. A current source is introduced in the proposed power amplifier to achieve ΔΣ digitised amplitude modulation. The current mode amplitude modulation is suitable for a high speed modulated signal such as an oversampled ΔΣ signal. View full abstract»

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  • GaN HEMT PA with over 84% power added efficiency

    Page(s): 1553 - 1554
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (251 KB)  

    Described are the design procedure and measured performance of a PA targeted for the W-CDMA downlink band exhibiting over 84% PAE at 2.14%GHz. The PA is designed with an uncharacterised GaN HEMT. A measurement-based design approach is used to optimise the source and load impedance at the fundamental frequency with class-F-1 harmonic terminations enforced. S-parameters extracted from a full-wave EM model characterising the impedance transformation from the virtual drain of the GaN HEMT to an output matching circuit are used to design class-F-1 second- and third-harmonic terminations. The highest efficiency for the final PA occurred 10 MHz off the design frequency, exhibiting 84.9 PAE, 8.2 W output power and 18.4 dB of gain at 2.15 GHz. View full abstract»

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  • LTCC dual-band stepped-impedance-stub filter constructed with vertically folded structure

    Page(s): 1554 - 1556
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Dual-band filtiers are common in dual-band transceivers, to attenuate interfering signals, and transmit the main signal in the desired passband. Reported is a compact low-temperature co-fired ceramic (LTCC) dual-band filter, constructed with a vertically folded structure and stepped-impedance stubs. The novel vertical interconnection scheme with its multilayered structure reduces the area of the filter by half. A 2.4/5.8 GHz dual-band experimental filter has been designed and assembled to verify the proposed design concept. S-parameter test results demonstrated good agreement between simulation and measurement. View full abstract»

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  • Low-cost coaxial-type single TO-can bidirectional optical subassembly

    Page(s): 1556 - 1557
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (361 KB)  

    A novel low-cost coaxial-type single transistor outline-can (TO-can) bidirectional optical subassembly (BOSA) using an all passive alignment BOSA platform and only one typical glass-sealed TO-can package is presented. This proposed BOSA platform is sufficiently compact to integrate in a single TO-can package and realises the reduction in cost by simplifying packaging processes. The measurement results of 3 dB bandwidth of the proposed single TO-can BOSA are 10.3 GHz for transmitter part and 8.2 GHz for receiver part, respectively. The clear eye diagram for transmitter part with 14.5 dB of the extinction ratio and 4.7 mW of output optical power and -26.3 dBm of receiver minimum sensitivity at a bit error rate of 10-10 are obtained under 2.488 Gbit/s operations. View full abstract»

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  • Tunable microcantilever sensors with embedded piezotransistors

    Page(s): 1557 - 1559
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    Microcantilevers with embedded piezotransistors formulate simple and sensitive MEMS sensors. In this reported work, three different p-type metal-oxide-semiconductor field-effect transistor (PMOSFET) embedded microcantilevers are fabricated and their responses to physical displacements are evaluated. Effects of gate bias on the drain current change and device sensitivity are investigated. Specifically, a wide tuning range above 200% is demonstrated for the PMOSFET with the width/length ratio of 5 within a gate bias span of 6%V. Such tunable feature can be very useful to compensate process variations and optimise device performance for maximum sensitivity. View full abstract»

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  • Advanced selective emitter structures by laser opening technique for industrial mc-Si solar cells

    Page(s): 1559 - 1561
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (229 KB)  

    A laser opening technique is employed as the photolithography process to form selective emitter (SE) structures on multi-crystalline silicon (mc-Si) substrates for the large-area (156 × 156 × mm2) solar-cell industry. The best efficiency of 16.35% is obtained with the developed SE structure after a damage removal process with optimisation of heavily and lightly doped dopants, which yields a gain of 0.88% absolute compared with that of a reference cell. Significantly, the SE mc-Si solar cell without the damage removal process can also reach a gain of 0.48% absolute. The developed SE process has simplicity, reliability, is fast, cost-effective, and could be effectively applied to mass production in industrial applications. View full abstract»

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  • Bounds on generalised integrated sidelobe level in waveforms with stopbands

    Page(s): 1561 - 1562
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (57 KB)  

    Bounds on the generalised integrated sidelobe level (GISL) are built for waveforms with stopbands, i.e. sparse frequency waveforms. The bounds predict the best achievable GISL for any average-pass-to-stopband power ratio in sparse frequency waveforms. The optimal condition for the lower bounds also suggests new approaches for designing sparse frequency waveforms with sidelobe constraints. View full abstract»

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  • Doppler ambiguity resolution for multiple PRF radar using iterative adaptive approach

    Page(s): 1562 - 1563
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    A new improved complex-valued iterative adaptive approach is proposed to effectively resolve Doppler ambiguity in multiple pulse repetition frequency (PRF) radar. Exact termination criterion for the proposed method is adopted based on the sparsity of Doppler spectrum. Numerical studies demonstrated the effectiveness of the proposed method. View full abstract»

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  • Estimation of wall parameters by exploiting correlation of echoes in time domain

    Page(s): 1563 - 1565
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (251 KB)  

    Compensation of the effects of wall on through-the-wall synthetic aperture radar (SAR) imaging is a main concern. Wall parameters are essential for the compensation, which are normally not known a priori. After analysis of echo configuration characteristics in time domain, a new procedure for estimating wall parameters is proposed, which is based on the idea of exploiting the correlation between the measured returns reflected from the wall and the corresponding estimates calculated from a SAR return model of the wall together with electromagnetic theory. The new approach deals with echo data without imaging or localisation processing, and has a less resolution requirement. 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