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Electronics Letters

Issue 16 • Date August 2 2012

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Displaying Results 1 - 25 of 42
  • In brief

    Page(s): 966
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  • Interview

    Page(s): 966
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  • Flexible power

    Page(s): 967
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1401 KB)  

    A group in Korea have created a highly flexible, simple to manufacture thermoelectric generator designed to be worn next to the skin to provide power continuously for portable devices. The generator's flexibility allows it to sit snugly against the skin for maximum heat transfer, even over larger areas. View full abstract»

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  • mm waves in the mix

    Page(s): 968
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (182 KB)  

    A millimetre-wave integrated mixer that uses around 75% less power than previous designs has been presented by researchers in Taiwan. The research team at National Central University used a Darlington-pair topology to reach V-band operation, and a thin-film LC-hybrid linear combiner in 90%nm CMOS to create a compact mixer chip that should be easy to produce on a large scale for future applications, such as wireless HD home networking, game consoles and car radars. View full abstract»

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  • 2.45 GHz high-gain electrically small antenna with composite right/left-handed ladder structure

    Page(s): 971 - 972
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Electrically small antennas are needed to lower further the cost of wireless elements. However, the antenna gain is constrained to the Harrington limit, while the impedance matching and directivity characteristics deteriorate in electrically small antennas. Using a dipole antenna loaded with a left-handed ladder structure is a promising technique for reducing the size of antennas. Reported is the design of a lumped-component loading left-handed antenna on the basis of the composite right/left-handed transmission line theory. A 4-unit cell left-handed dipole antenna with a size of 20 mm (0.16λ0) was fabricated with a T-junction balun. The actual gain of the fabricated antenna was -0.01-dBi, which was about 1-dB lower than the Harrington limit and the highest ever achieved for fabricated antennas operating at around 2.45-GHz (kr=0.502). The directivity measured in the E-plane was similar to that of typical half-wavelength dipole antennas. View full abstract»

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  • Time-modulated reflector array

    Page(s): 972 - 974
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    The concept of a time-modulated reflector array (TMRA) is introduced and analysed. The TMRA is proposed as an alternative to conventional time-modulated array designs. The TMRA is potentially much simpler to implement in hardware than the conventional time-modulated array as it does not require a complex feed network. The results of a simple analysis of a TMRA based on an array-factor model combined with Fourier-series theory is presented to illustrate the basic operation of the system and to show that the TMRA exhibits similar characteristics to conventional time-switched arrays. A more realistic TMRA based on pin diode controlled dipole elements is also modelled using a full-wave electromagnetic simulator and the performance of this system is compared to that obtained from array-factor theory. View full abstract»

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  • Band-reject ultra-wideband monopole antenna using patch loading

    Page(s): 974 - 975
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (437 KB)  

    Proposed is a new simple technique for achieving band rejection characteristics in ultra-wideband monopole antennas. Two band notches were added to an existing UWB antenna by gluing a padding patch printed on a small single-layer piece of commercial substrate. The design of the new proposed structure has a controllable rejection in the 5 GHz WLAN and 8 GHz ITU frequencies while maintaining a wideband performance from 2.9 GHz to more than 12 GHz based on VSWR ≤ 2. A good agreement between measurement and simulation was achieved. Measurements confirm that the technique introduces negligible antenna radiation pattern distortion except at the notched frequencies. View full abstract»

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  • Compact diversity antenna for UHF RFID readers

    Page(s): 975 - 977
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (355 KB)  

    A diversity antenna combining four inverted-F antennas (IFAs) is evaluated for UHF RF identification (RFID) readers. Polarisation and pattern diversities are obtained for a sequentially rotated configuration of the IFAs. Mutual coupling between ports is minimised by etching quarter-wavelength slots into the ground plane. The resulting envelope correlation coefficient is less than 0.003 in the working band. A switching diversity scheme is then applied to evaluate the tags readability in a lab environment. It is shown that the antenna diversity enhances the reading range compared to a circularly or a linearly polarised antenna of the same size. View full abstract»

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  • Compact quad-band reconfigurable antenna for mobile phone applications

    Page(s): 977 - 979
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    A compact reconfigurable antenna for quad-band (GSM/DCS/PCS/ WCDMA) mobile phone applications is proposed and experimentally investigated. By independently controlling the on/off states of a pin diode placed on a radiating element, the proposed antenna can be operated in the planar inverted-F antenna (PIFA) and loop modes, respectively. The measured results show that the 6 dB reflection coefficient bandwidths of the proposed antenna are 8.7% (880-960 MHz) and 14.3% (1950-2250 MHz) in the PIFA mode and 21.5% (1620- 2010 MHz) in the loop mode. By electrically selecting between the two modes, a variety of communication systems can be conveniently served through only one antenna. View full abstract»

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  • Multiple-bridge-loop reader antenna for improved positioning and localisation

    Page(s): 979 - 980
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    Introduced is a novel HF RFID bridge reader antenna suitable for accurate positioning and localisation. Conventional HF RFID reader antennas can only indicate the presence or absence of a tag(s). The proposed reader antenna uses multiple loops to form multiple bridges so that the position of tags with respect to the reader recognition area can be obtained. The bridge-loop configuration can split the overall reader recognition area into sub-zones so that the location of the detected tag(s) with respect to these zones can be identified to help to improve positioning accuracy. Simulation and experimental results confirm the operation of the proposed bridge-loop HF RFID reader antenna. View full abstract»

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  • Octave-band, multi-resonance CPW-fed small slot antenna for UWB applications

    Page(s): 980 - 982
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (614 KB)  

    A novel multi-resonance CPW-fed slot antenna, for UWB applications, is proposed. The proposed antenna consists of a modified fan-shaped radiating stub and a sprocket-shaped ground plane provides a wide usable fractional bandwidth of more than 155% (2.39-24.53 GHz). By inserting eight pairs of gear-shaped teeth on the sprocket-shaped ground plane, an additional eight resonances are excited and hence much wider impedance bandwidth can be produced. Unlike other antennas reported in the literature to date, the proposed antenna displays a good omnidirectional radiation pattern even at higher frequencies. The designed antenna has a small size of 30×30 mm2. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behaviour within the UWB frequency range. View full abstract»

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  • On the efficiency of frequency reconfigurable high-Q antennas for 4G standards

    Page(s): 982 - 983
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (198 KB)  

    In the actual context of reducing antenna size and operating in multiple bands tunable antennas are investigated. Moreover, high-Q and low-Q tunable antennas are compared with respect to their efficiency. The loss issue that tunable high-Q antennas present is addressed. Using a variable capacitor as a tuning mechanism, simulations and measurements of a self-resonating antenna show the mismatch and the radiation efficiencies of the high-Q and the low-Q antennas. The investigated frequencies are in the low band of the 4G standard. Measurements are conducted for different tuning stages and the study shows that the high-Q design performs worse than the low-Q one. A 1.4 dB degradation in total efficiency is observed for a high-Q antenna in a tunable system. View full abstract»

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  • Pattern reconfigurable antenna for wireless sensor network system

    Page(s): 984 - 985
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (390 KB)  

    An antenna for a wireless sensor network for an indoor environment is proposed. The proposed antenna is composed of an artificial magnetic conductor reflector, two branched radiators, and a power divider including a switched-line phase shifter. Two branched radiators act as four bent monopoles or two crossed dipoles by the switched-line phase shifter. The power divider provides two branched radiators inphase or out of phase power which makes a side directional pattern or a normal directional pattern, respectively. The proposed antenna has less than 10 mm height with 100 × 100 mm area and more than 100 MHz bandwidth at 2.4 GHz. View full abstract»

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  • Wearable textile antenna in substrate integrated waveguide technology

    Page(s): 985 - 987
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (299 KB)  

    A novel wearable substrate integrated waveguide antenna fabricated entirely from textile materials is presented. The cavity-backed slot antenna operates in the 2.45 GHz industrial, scientific and medical band, for short range communication between rescue workers. A prototype of the antenna was fabricated and tested: good performance was obtained in terms of input matching and radiation pattern. Moreover, measurements performed on the antenna after bending and integration into clothing indicate high robustness against deformation and low influence of the human body on antenna performance, making the design well-suited for on-body use. View full abstract»

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  • All-CMOS low supply voltage scattered thermal monitoring front-end

    Page(s): 987 - 988
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    Presented is a low-voltage all-CMOS scattered thermal monitoring architecture front-end designed in a 0.5 μm process. To support low-voltage operation for scaled CMOS technologies, MOSFETs operating in the subthreshold region and an amplifier with a bulk-driven technique are used. To reduce the offset error caused by device mismatches, gain boosting, dynamic offset cancellation and dynamic element matching methods are adopted. The sensor node occupies an area of 90 × 70 μm2. The measured minimum supply voltage was 1.1 V over a -55 to 125°C temperature range. The front-end was chamber tested and the performances are reported. Experiments demonstrated the multi-corner thermal monitor detecting on-chip temperature gradients from 1.2 to 26°C/mm. View full abstract»

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  • Charge compensation technique for switched-capacitor circuits

    Page(s): 988 - 990
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (547 KB)  

    A charge compensation technique is proposed for switched-capacitor S/H circuits and integrators. The compensated stages achieve better linearity with low power and relaxed sampling noise specifications. Analysis and simulations show that high linearity can be achieved, even while consuming low power. View full abstract»

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  • Second-stage tuning procedure for analogue CMOS design reuse methodology

    Page(s): 990 - 992
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (343 KB)  

    Proposed is a two-stage analogue circuit design reuse methodology by extending existing fabrication process rescaling procedures with a follow-on systematic tuning procedure stage based on DC output voltage scaling. It increases the potential for design reuse with short-channel MOSFET circuit designs when compared to the current single-stage rescaling work. Two Miller amplifier circuits were designed in 0.18 and 0.13 μm CMOS processes in order to analyse circuit performance achieved with the proposed method compared to the existing methods. The additional tuning stage results in an improved amplifier gain up to 16 dB and up to 2.5 times faster settling time compared to single-stage scaling with 33% power reduction and 28% smaller silicon area when compared to the original design. View full abstract»

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  • Gabor-based weighted region covariance matrix for face recognition

    Page(s): 992 - 993
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    A novel image region descriptor, named the Gabor-based weighted region covariance matrix (GWRCM), is proposed by incorporating the weighting matrices into a Gabor-based region covariance matrix (GRCM). Based on the weighting matrix, the proposed approach can assign different weights for pixels in different face parts, so it preserves more discriminating information than the GRCM for face recognition. Experimental results show that the proposed GWRCM approach outperforms other algorithms in terms of recognition accuracy. View full abstract»

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  • Geometrically inspired MRF for moving object detection from mobile stereo camera

    Page(s): 993 - 995
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (381 KB)  

    Detecting moving objects from an image sequence is challenging, especially when the camera is moving and the background varies significantly in every frame. In addition, classifying moving objects using only their appearances creates ambiguities in complex scenes. In this sense a Markov random field (MRF) approach is proposed incorporating a stereo vision-based structure-from-motion scheme in order to robustly detect the moving objects from image sequences. In this MRF formulation, the new energy terms of a high-order likelihood and a temporal pairwise potential are added to improve the detection performance further. The performance of the proposed method is demonstrated from publicly available datasets. View full abstract»

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  • Onboard vehicle detection and tracking using boosted Gabor descriptor and sparse representation

    Page(s): 995 - 997
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (287 KB)  

    Proposed is a new onboard vehicle detection method based on a part-based model. It uses several boosted Gabor descriptors of keypoints to represent the vehicle. To perform detection, the sparse representation-based classifier is adopted to classify the extracted keypoints in video frames. Then, by using the K-means algorithm, vehicle candidates with high-density classified keypoints are generated. With the keypoint matching adopted, these candidates can be verified, and the matched pairs are meanwhile to be used for vehicle tracking. Experimental results show that the proposed method is robust to environmental changes as well as achieving high detection accuracy. View full abstract»

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  • Data structures and control mechanisms for multi-target swarming simulators

    Page(s): 997 - 998
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (271 KB)  

    Data structures and control mechanisms for multi-target swarming software simulators are presented. The advantage of the proposed approach is that a swarm, besides local self-organisation, is able to accept higher level directives on target priorities. Also, the presented mechanisms enable a swarm to dynamically change its participants' assignment on every target appearance or removal in simulation. View full abstract»

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  • Space-time/space-time-frequency-coding-based MIMO-OFDM over power line channels

    Page(s): 999 - 1000
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (239 KB)  

    A space-time/space-time-frequency-coding-based 2 × 2 multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) power line communication system that employs a maximum ratio combining receiver, also called a rake receiver, not only improves the bit error rate performance (relative to existing schemes) but is also insensitive to crosstalk. View full abstract»

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  • Wobble-based on-chip calibration circuit for temperature independent oscillators

    Page(s): 1000 - 1001
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (274 KB)  

    An automatic calibration circuit for temperature- and process-independent oscillators and timing circuits is presented. The circuit monitors the dynamic gate-source voltage of a MOS transistor of which the temperature is changing. By adapting the bias current through this transistor towards the zero-temperature-coefficient point of the VGS, the gate-source voltage can be used in temperature-independent timing circuits. Because of the dynamic nature of this regulation circuit, the technique is insensitive to mismatch and process variations. The presented technique is applied to a low-noise oscillator to make it less temperature sensitive with a factor of 8. View full abstract»

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  • Electrical tunable L-band absorbing material for two polarisations

    Page(s): 1002 - 1003
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (434 KB)  

    An electrical tunable L-band absorbing material for two polarisations is presented. The proposed absorber consists of a metal resonator and four surrounded metal lines which are connected by pin diodes, and exhibits the tunable range of reflectivity reaching to -40 dB for both polarisations. In particular, for TM polarisation, the working frequency is also tunable from 1.9 to 2.1 GHz due to the conversion between two distinct resonance modes supported by the resonator and surrounding lines, respectively. View full abstract»

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  • Radiation properties of coaxial-to-coplanar transitions in K band

    Page(s): 1003 - 1004
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (249 KB)  

    A radiation and electro-magnetic (EM) field analysis of commercially available coaxial-to-coplanar transitions is presented. Radiation is quantified by measuring a crosstalk component between two Southwest Microwave's transitions using a reflective planar calibration standard placed inside. Predictive simulation results are compared to the measured data and good agreement is reported. The proposed evaluation method is useful to evaluate quality of the transition and its radiation properties. Results can be used to estimate the uncertainty budget of the calibrated measurement with respect to the measured radiation. Obtained results are promising to help further development of hardware or software solutions to suppress or minimise the radiation emerging from the launcher. 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