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Electronics Letters

Issue 7 • Date March 28 2013

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Displaying Results 1 - 25 of 46
  • In brief

    Page(s): 436
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  • Interview

    Page(s): 436
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    Professor Paul Berger from Ohio State University in the US talks about the research behind his group's Letter: 'Towards in vivo biosensors for lowcost protein sensing' on page 450. View full abstract»

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  • A good fit

    Page(s): 437
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    A US-based team have expanded their model of III-V materials interfaces to include series resistance and dielectric leakage behaviour. View full abstract»

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  • Nod off - switch off

    Page(s): 438
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (249 KB)  

    Researchers in China have presented a device for identifying when a patient is asleep and accordingly to adjust deep brain stimulation (DBS) in Parkinson's disease sufferers. The device is worn on the wrist and can communicate with the implanted stimulating system to control its activity. View full abstract»

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  • Bandwidth enhancement of ground antenna using resonant feeding circuit

    Page(s): 441 - 442
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    A loop-type ground antenna with wide-band operation is proposed for USB dongle applications. The solution for improving the bandwidth is based on a resonant feeding circuit that includes both an inductor and a capacitor. By choosing an appropriate ratio of the inductance to the capacitance, the impedance bandwidth (VSWR <; 2) is 21.8<; at 2.2 GHz, sufficient bandwidth to cover both the WCDMA and WiMax frequency bands. View full abstract»

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  • Compact shorted inverted-L antenna with circular polarisation for RFID handheld reader

    Page(s): 442 - 444
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (413 KB)  

    Two shorted inverted-L radiating elements are located on the orthogonal corner of the square substrate and connected to each output port of a Wilkinson power divider. A shorted inverted-T strip is placed on the other corner of the square for a perturbing resonator to generate circularly-polarised (CP) radiation in the UHF band. Proper adjusting of the horizontal and vertical lengths of the inverted-T strip will differentiate two orthogonal linearly modes with 90° phase difference for a good CP radiation. Simulated and measured results indicate that the proposed structure can achieve circular-degree polarisation operation. A measured impedance bandwidth (VSWR ≤2) of about 16.4% (810-960 MHz) and a 3 dB axial-ratio (AR) bandwidth of about 4.4% (890-930 MHz) at 915 MHz were obtained. View full abstract»

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  • Dual-band circularly-polarised Spidron fractal microstrip patch antenna for Ku-band satellite communication applications

    Page(s): 444 - 445
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (449 KB)  

    A dual-band circularly-polarised antenna implemented on a single substrate is proposed for Ku-band satellite communication. A microstrip-fed Spidron fractal patch is utilised to achieve dual-band resonance and circular polarisation. The proposed antenna, with dimensions of 50 × 50 × 1.52 mm3, has also been fabricated and tested. The measured -10 dB reflection bandwidths are 8.7- (11.44-12.48 GHz) and 6.6- (13.47-14.39 GHz), exhibiting a small resonant frequency ratio of 1.15. The 3 dB axial ratio bandwidths for the lower band and the upper band are 2.96 and 1.68-, respectively. View full abstract»

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  • Electronically scanned Rotman lens antenna with liquid crystal phase shifters

    Page(s): 445 - 447
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    The performance of a Rotman lens, which forms fixed beams at 0°, ±15° and ±30°, is augmented using liquid crystal phase shifters to simultaneously steer each beam by up to ±7.5°. Measured results are used to demonstrate that the true time delay property of the antenna and voltage controlled phase shifters can be exploited to provide continuously scanned beams with full coverage over an angular range of ±37.5°, and with operation over the band 6-10 GHz. View full abstract»

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  • Ground radiation method using slot with coupling capacitors

    Page(s): 447 - 448
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (398 KB)  

    An innovative antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed. This method is based on a capacitively loaded slot placed at the centre of the ground plane. The ground plane is 50 × 15 mm in length and width, respectively, which is the size typically used in USB dongles and headsets. The ×10 dB impedance bandwidth is 12.9× at 2.4 GHz, fully covering the WiMax, Wi-Fi and Bluetooth frequency bands. View full abstract»

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  • Fuzzy extreme learning machine for classification

    Page(s): 448 - 450
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (62 KB)  

    Compared to traditional classifiers, such as SVM, the extreme learning machine (ELM) achieves similar performance for classification and runs at a much faster learning speed. However, in many real applications, the different input points may not be exactly assigned to one of the classes, such as the imbalance problems and the weighted classification problems. The traditional ELM lacks the ability to solve those problems. Proposed is a fuzzy ELM, which introduces a fuzzy membership to the traditional ELM method. Then, the inputs with different fuzzy matrix can make different contributions to the learning of the output weights. For the weighted classification problems, FELM can provide a more logical result than that of ELM. View full abstract»

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  • Towards in vivo biosensors for low-cost protein sensing

    Page(s): 450 - 451
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (243 KB)  

    In vivo biosensing requires stable transistor operation in high-salt concentration bodily fluids while exhibiting impermeability to mobile alkali ions that would otherwise render the metal-oxide-semiconductor (MOS) threshold voltage to drift. Metal oxide semiconductor capacitor structures using Al2O3 as the gate dielectric were soaked in a sterile physiological buffer solution (PBS) up to 24 hours and for thicknesses from 100 to 10 nm. The triangular voltage sweep technique characterised alkali ion penetration, and measured no detectable alkali ions for the Al2O3 capacitors. By contrast, the dose of alkali ions in silicon dioxide MOS capacitors steadily increased with increasing soak times in the PBS solution. View full abstract»

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  • Wireless wrist-wearable wake/sleep identification device for closed-loop deep brain stimulation

    Page(s): 452 - 453
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    Deep brain stimulation is an important therapy for Parkinson's disease patients. However, the current deep brain stimulator is open loop and cannot automatically adapt the stimulation according to the patient's condition. In this reported study a real-time wake/sleep identification device has been developed to wirelessly control the stimulation according to the patient's wake/sleep states. The wake/sleep identification was based on the wrist movement, and the identified result was transmitted wirelessly to the implantable pulse generator. This device showed a reliable radio frequency communication within 2 m and a low level of current consumption. This device also showed a good performance of real-time wake/sleep identification on Parkinson's disease patients. This study provides a promising application in the closed-loop deep brain stimulation, as well as other applications in medical services, such as night care, and fall alarm. View full abstract»

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  • Multi-function ESD protection circuit for UHF RFID devices in CMOS technology

    Page(s): 453 - 455
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (290 KB)  

    The design and implementation of an electrostatic discharge protection suitable for UHF RFID devices in CMOS technology is presented. The circuit implements three fundamental functions for the RF interface: power limiting, backscatter modulation and electrostatic discharge protection. Since all functions are achieved by the same MOS device the additional shunt capacitance at the RF inputs is limited. Therefore the maximum reading distance of the RFID device is improved without sacrificing the electrostatic protection level. View full abstract»

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  • Single-stage LED driver with low bus voltage

    Page(s): 455 - 457
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    A single-stage driver is proposed. The LED driver is obtained by integrating an interleaved boost circuit and an LLC resonant converter. Since the interleaved circuit is adopted here, the input voltage is divided into two parts, each part sharing with one switch of the LLC resonant converter forms a boost circuit in discontinuous mode, and the power factor correction function and low bus voltage are realised. Since the LLC resonant converter is adopted, the converter works in soft switching state, which increases the efficiency of the system. A 100 W prototype is achieved to prove the analysis of the LED driver, and the efficiency of the LED driver is as high as 91% in full load. View full abstract»

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  • Improvement of nonlinear diffusion equation using relaxed geometric mean filter for low PSNR images

    Page(s): 457 - 458
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (198 KB)  

    A new method to improve the performance of low PSNR image denoising is presented. The proposed scheme estimates edge gradient from an image that is regularised with a relaxed geometric mean filter. The proposed method consists of two stages; the first stage consists of a second order nonlinear anisotropic diffusion equation with new neighboring structure and the second is a relaxed geometric mean filter, which processes the output of nonlinear anisotropic diffusion equation. The proposed algorithm enjoys the benefit of both nonlinear PDE and relaxed geometric mean filter. In addition, the algorithm will not introduce any artefacts, and preserves image details, sharp corners, curved structures and thin lines. Comparison of the results obtained by the proposed method, with those of other methods, shows that a noticeable improvement in the quality of the denoised images, that were evaluated subjectively and quantitatively, is produced. View full abstract»

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  • Shadow modelling and correction techniques in hyperspectral imaging

    Page(s): 458 - 460
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    Shadowing and illumination variations, caused by scene topography or non-uniform lighting, are present in virtually all image data. Given its prevalence and nuisance value when making quantitative image measurements, the development of accurate shading compensation techniques is essential. The linear mixture model of image formation is broadly employed when dealing with hyperspectral data but makes no explicit provision for shading and this can lead to inaccurate analysis results. In this reported work, the effect of shading on a hyperspectral image is demonstrated, and new methods for mitigating the effect using a forced-zero endmember and conical sub-simplex projection are presented. It is shown that together they provide the most accurate and theoretically sound shadow-corrected data. View full abstract»

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  • Compression of redundancy free trellis stages in turbo-decoder

    Page(s): 460 - 462
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (221 KB)  

    For turbo codes with a coding rate close to one, the high puncturing rate induces long sequences of trellis without a redundancy bit. A simplification technique to compute the final state of a sequence of redundancy free trellis stages (RFTSs) is presented. It compresses a sequence of RFTSs of length N into a sequence of RFTSs of length m - 1 + (N mod (m - 1)), where m is the number of states of the trellis. The computation is reduced accordingly. View full abstract»

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  • Effective HARQ code rate modelling for LTE

    Page(s): 462 - 464
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (299 KB)  

    Proposed is an intuitive model for the effective code rate of HARQ-coded LTE transmissions. The model is derived from the circular structure of the rate matching buffer employed in LTE. Comparison with prior results, which were obtained by empirically extracting the code rates from the rate matcher, show the accuracy of the presented, entirely analytical, model. View full abstract»

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  • Improved pedestrian tracking through Kalman covariance error selective reset

    Page(s): 464 - 465
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (277 KB)  

    Kalman filtering is one of the most widely used approaches to handling inertial sensors in pedestrian tracking systems. This technique uses a covariance error matrix to estimate position. This reported study leads to the hypothesis that there is no correlation between some elements of this matrix from one step to the next. Therefore, a selective reset of these elements at the end of each step improves position estimation. A set of these elements is proposed, and a statistical study is conducted using 32 data traces from the same path. Four parameters are analysed: the correction mean length, the position error, the altitude error and the travelled distance. As a result, all of these parameters obtain a loose statistical significance when the covariance error selective reset is applied. View full abstract»

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  • Particle swarm optimisation with Kalman correction

    Page(s): 465 - 467
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (165 KB)  

    A novel particle swarm optimisation (PSO) method with guaranteed convergence is proposed which is useful for various optimisation problems. This proposed algorithm searches for the optimum point by the PSO algorithm and at each iteration the optimum location found so far are corrected by the Kalman correction mechanism. This global convergence Kalman PSO (GKPSO) algorithm has been tested for many benchmark problems and the results compared with another popular PSO algorithm with a neighbourhood operator. The proposed algorithm converges faster than the other and also provides better quality of solution. Convergence to the global optimum for this proposed algorithm has been proved. View full abstract»

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  • Square root algorithm in Fq for q = 2s + 1(mod 2s+1)

    Page(s): 467 - 469
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (391 KB)  

    Presented is a square root algorithm in Fq which generalises Atkins's square root algorithm [see reference 6] for q ≡ 5 (mod 8) and Muller's algorithm [see reference 7] for q ≡ 9 (mod 16). The presented algorithm precomputes a primitive 2s-th root of unity ξ where s is the largest positive integer satisfying 2s|q - 1, and is applicable for the cases when s is small. The proposed algorithm requires one exponentiation for square root computation and is favourably compared with the algorithms of Atkin, Müuller and Kong et al. View full abstract»

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  • Inverter-based second-order sigma-delta modulator for smart sensors

    Page(s): 469 - 471
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (303 KB)  

    Presented is a fully-differential inverter-based switched-capacitor second-order sigma-delta modulator for smart sensor applications. To reduce the supply voltage, the power consumption and the chip area, a simple inverter is used to replace the operational transconductance amplifier in the traditional integrator. The supply voltage can be lower than the summation of the absolute threshold voltages of the PMOS and NMOS transistors in the inverter. The described modulator has been designed and fabricated in AMI 0.5 μm CMOS process. Measurement shows that it can work under 1.5 V supply voltage and provide 55.39 dB signal-to-noise and distortion ratio (SNDR). Simulation also shows that the modulator can work under 0.7 V supply voltage and provide 59.38 dB SNDR in IBM 180 nm CMOS process. View full abstract»

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  • 0.6mW 6.3 GHz 40nm CMOS divide-by-2/3 prescaler using heterodyne phase-locking technique

    Page(s): 471 - 472
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (349 KB)  

    A dual-modulus prescaler based on the heterodyne phase-locking technique is presented. Different to the conventional LC tank based phase-locked loop, by directly locking at two injection-locked ring oscillators simultaneously, a dual-modulus operation is achieved while a wide-range operating, significantly reduced settling time and low power consumption are achieved. Implemented in a standard 40nm CMOS process, the proposed divide-by-2 and 3 dual-modulus prescaler achieves an operating frequency of 6.3GHz with a measured power consumption of 0.6mW from a 1.1V supply. View full abstract»

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  • 3.88 dB NF 60 GHz CMOS UWB LNA with small group-delay-variation

    Page(s): 472 - 474
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (198 KB)  

    A low power and low noise figure (NF) 60 GHz low-noise amplifier (LNA) with excellent phase linearity using standard 90 nm CMOS technology is reported. The LNA comprises a common-source (CS) stage followed by a cascode stage and a CS stage. The LNA consumes 14.1 mW, achieving S11 better than - 10 dB for the frequencies 55.1-59.5 GHz, S22 better than - 10 dB for the frequencies 55.1-59.4 GHz, and group delay variation smaller than - 13.25 ps for the frequencies 50.4-63 GHz. Additionally, high and flat S21 of 9.9 ± 1.5 dB is achieved for the frequencies 50.4±62.9 GHz, which means the corresponding 3 dB bandwidth is 12.5 GHz. Furthermore, the LNA achieves a minimum NF of 3.88 dB at 55.5 GHz and an NF of 4.73 ± 0.85 dB for the frequencies 50±63.5 GHz, one of the best NF results ever reported for a 60 GHz CMOS LNA. View full abstract»

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  • 2.5-7 ghz single balanced mixer with integrated ruthroff-type balun in 0.18 μm cmos technology

    Page(s): 474 - 475
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    An on-chip Ruthroff-type balun fabricated in tsmcTM 0.18 μm CMOS technology has been realised and used in a single balanced mixer. By using the phase compensation line and appropriately choosing the characteristic impedance of transmission lines, the balun was realised with a minimum insertion loss of 0.71 dB and the 1 dB bandwidth over a frequency range from 3.2 to 8.4 GHz. The compact size of 0.088 mm2 is achieved owing to the short length of the transmission line winding, approximately 1/18 λg, and the adoption of broadside-coupled and spiral-shape structures. A simple single balanced mixer with the Ruthroff-type balun was then designed to demonstrate the capability of the broadband and low-loss balun. A minimum conversion loss of 12.48 dB with a 3 dB bandwidth from 2.5 to 7 GHz was measured at the LO drive of only 6 dBm. The chip area, including pads, is 0.49 mm2. 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