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Electronics Letters

Issue 13 • Date June 23 2011

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Displaying Results 1 - 25 of 36
  • In brief

    Publication Year: 2011 , Page(s): 730
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  • CVD, Blue and The Wire

    Publication Year: 2011 , Page(s): 730
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (101 KB)  

    Researchers in France have fabricated light emitting diodes based on GaN core/shell wires grown by metal organic chemical vapour deposition on Silicon substrates, with blue electroluminescence at 450 nm, reported for the first time. Their results presented in this issue of Electronics Letters open up a possible advance in lighting. Even after the initial LED breakthrough that occurred at the beginning of the century, with the emergence of high-brightness white LEDs - and the improvement in performance since then - the general lighting market is still not widely open to LEDs. Wire-based LEDs have the potential to greatly extend the performance limits of solid-state lighting. View full abstract»

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  • SQUIDS mix it up

    Publication Year: 2011 , Page(s): 731
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    Researchers in Australia have reported the use of a high temperature superconducting resistive superconducting quantum interference device (HTS R-SQUID) for the first time as a self-pumped mixer in the GHz frequency range. This opens the way for potential innovations in wireless receiver technology, where many HTS passive components with superior performance have already been employed. View full abstract»

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  • Forging a new chain

    Publication Year: 2011 , Page(s): 732
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (285 KB)  

    A piezoelectric actuator MEMS for middle ear implants has been proposed by a team in Spain. Their proposed design includes a novel attachment location and promises smaller cost, size and power consumption. View full abstract»

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  • Preconditioned alternate projections method to synthesise conformal array

    Publication Year: 2011 , Page(s): 735 - 736
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    A preconditioned alternate projections method is proposed for pattern synthesis in a conformal array. The algorithm applies the aperture projection with the null points adjusting technique to initialise the problem, which enhances the ability of the solution greatly; moreover, the improved project operator accelerates the convergency speed of the iteration. Using this algorithm, the low sidelobe scan beam pattern for a 12-element sectoral cylinder microstrip array is obtained with the mutual coupling considered. View full abstract»

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  • Two-inductor loaded loop antenna for mobile phones

    Publication Year: 2011 , Page(s): 736 - 737
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (254 KB)  

    A two-inductor loaded small loop antenna for mobile phone applications is presented. To optimise the loop antenna, positions and values of the two inductors in the loop antenna are changed by a simple genetic algorithm. The algorithm makes the antenna operate in GSM and DCS bands. Simulated results are compared with measured results and good agreement is reported. View full abstract»

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  • Wideband circularly polarised antenna using two linked annular slots

    Publication Year: 2011 , Page(s): 737 - 739
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (258 KB)  

    An annular-slot antenna composed of two linked annular slots is presented. The return loss and the axial-ratio bandwidths are enhanced by tuning the distance between the two centres of the two annular slots. Under the optimum condition, the two circular patches associated with the two annular slots are found to be separated from each other. The measured 3 dB axial-ratio bandwidth is 1.4 GHz (46.7 ) centred at 3 GHz. View full abstract»

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  • Piezo-actuator MEMS to substitute tympanic-ossicular system

    Publication Year: 2011 , Page(s): 739 - 740
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (315 KB)  

    A micro-machined transducer and sensor for a new implantable audioprosthesis to substitute the human tympanic-ossicular system has been developed. The device is intended to restore hearing by implanting it in patients with a damaged or surgically removed ossicular chain. Different configurations of devices have been analysed. The proposed piezo-actuator has a diameter of 1.0 mm with a total thickness of 3.5 m, which reaches deformations of up 16.8 nm with a typical excitation of 3 V. View full abstract»

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  • Simulation technique for RF oscillators

    Publication Year: 2011 , Page(s): 740 - 742
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (185 KB)  

    A new method for simulating radio-frequency (RF) oscillators is presented. The asymptotic numeric method enables the efficient simulation of the transient response of such oscillators. Simulation results are provided for a practical RF oscillator circuit to validate the approach. View full abstract»

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  • Floating capacitor switching SAR ADC

    Publication Year: 2011 , Page(s): 742 - 743
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (231 KB)  

    An energy-efficiency floating-capacitor switching (FCS) scheme is proposed for successive approximation register (SAR) analogue-to-digital converters (ADCs). By rearranging the switching order from the smallest capacitor to the largest one, the switching energy can be significantly reduced, especially in the first several DAC switchings. With the presented scheme, a 97.66% less switching energy can be achieved compared to the conventional architecture (Ginsburg and Chandrakasan, 2005). View full abstract»

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  • Highly-linear time-difference amplifier with low sensitivity to process variations

    Publication Year: 2011 , Page(s): 743 - 745
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (274 KB)  

    A novel time-difference amplifier (TDA) is presented. The proposed circuit has a larger linear operation region with less sensitivity to process variations than the state-of-the-art TDAs. Two TDAs with gains of two and 20 have been simulated in a 65 nm CMOS process to validate the proposed architecture. Simulation results show less than 0.1% gain error for ±400 ps input time difference range, ten times the range of conventional TDAs. The proposed TDA consumes 740 μW from a 1 V supply. View full abstract»

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  • Two-shot sparse depth estimation using adaptive structured light

    Publication Year: 2011 , Page(s): 745 - 746
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    Presented is a low-cost two-shot approach employing a projector and a camera to recover an object's sparse shape. The algorithm is based on projecting a grid pattern of adaptive colours which vary with the object and then matching grid points between the projected pattern and the image captured under this adaptive structured light. Results show the performance of this adaptive colours approach is superior to using constant colours in shape recovery of real-world objects with strong colours and textures under ambient light conditions. View full abstract»

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  • Precoder/two-stage equaliser for block-based single-carrier transmission with insufficient guard interval

    Publication Year: 2011 , Page(s): 746 - 748
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (178 KB)  

    Proposed is a zero-inserting precoder and a two-stage linear equaliser, to shorten the guard interval in block-based single-carrier modulation. The first-stage equaliser consists of a linear single-tapper-subcarrier frequency-domain equaliser. The second-stage equaliser maximises the SINR, in the time-domain, based on the interference-plus-noise estimated from the zero-padded sub-intervals of the single-carrier modulation. This proposed scheme is applicable even without cyclic prefixing. View full abstract»

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  • Design of suitable permutations for irregular turbo codes

    Publication Year: 2011 , Page(s): 748 - 749
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (193 KB)  

    Proposed is a method based on the Dijkstra's algorithm and an estimation of the distance to search for efficient interleavers, adapted to irregular turbo codes, in order to reduce the flattening effect. Simulations show that a gain of three decades and a half in the error floor is obtained for short block sizes. View full abstract»

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  • Iterative decoding of turbo convolutional codes over noisy two-user binary adder channel

    Publication Year: 2011 , Page(s): 749 - 751
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (166 KB)  

    Iterative decoding of turbo convolutional codes for the noisy two-user binary adder channel is investigated. It is shown that iterative BCJR decoding yields considerable gain after just a few iterations for low-complexity codes constructed from turbo convolutional codes. View full abstract»

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  • Compact coupled line broadband microstrip to slotline transition

    Publication Year: 2011 , Page(s): 751 - 752
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (179 KB)  

    A compact broadband microstrip to slotline transition is designed and experimentally studied. An elliptical tapered profile and patches are used to minimise the discontinuity effect of field variation from microstrip to slotline within a short range. A prototype of the back-to-back version transition is also fabricated. Measured results validate the design concept. View full abstract»

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  • Baseband NGD circuit with RF amplifier

    Publication Year: 2011 , Page(s): 752 - 754
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    This presented report deals with the synthesis of baseband negative group delay (NGD) RF circuits. A theoretical approach based on the S-parameter analysis is presented. The NGD circuit synthesis formulae according to the desired gain value, NGD level and bandwidth are established. To validate the theoretical approach, a two-stage NGD device employing LNAs was investigated. Baseband NGD with minimal value below -1-ns with 400-MHz frequency bandwidth was found. The synthesised circuit presents a gain higher than 5-dB. To highlight the functionality of the NGD effect, time-domain analysis was performed. The NGD circuit allows the reduction of signal pure delays caused by telecom devices and is useful for the correction of interleaved symbols in RF/digital numerical systems. View full abstract»

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  • Coherence-free cascade IIR microwave photonic filter with high Q factor

    Publication Year: 2011 , Page(s): 754 - 755
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (194 KB)  

    A new high-Q infinite impulse response (IIR) microwave photonic filter is demonstrated, in which two active recirculating delay line loops based on a semiconductor optical amplifier (SOA) are cascaded. Due to cross-gain modulation in the SOA, interferences between light beams travelling along different paths are removed, ensuring stable operation and linearity of the electrical transfer function. The whole transfer function comprises a term representing a cascade response of two IIR filters, which significantly increases the free spectral range and the Q factor. The filter exhibits a Q factor of 1870 with a rejection ratio of 25 dB. View full abstract»

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  • Compact dual-band semi-lumped bandpass filter with LTCC technology

    Publication Year: 2011 , Page(s): 755 - 757
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (278 KB)  

    A novel low-temperature co-fired ceramic (LTCC) dual-band bandpass filter with compact size is reported. By using three semi-lumped resonators, not only the upper passband frequency can be conveniently tuned, but also the transmission zeros generated between the two passbands can be easily controlled by the elements of each resonator. A 2.5/5.2GHz dual-band experimental filter has been designed and fabricated to verify the proposed design concept. Based on the vertically-folded structure and LTCC technology, the filter only occupies an area of 5.1 × 4.6 × mm2. View full abstract»

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  • Compact UWB bandpass filter with two notched bands based on electromagnetic bandgap structures

    Publication Year: 2011 , Page(s): 757 - 758
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (241 KB)  

    A novel and compact ultra-wideband (UWB) bandpass filter with dual narrow notched bands based on two mushroom-type electromagnetic bandgap (EBG) structures is presented. The UWB BPF comprises two coupled lines which are coupled to the open-ended coplanar waveguide on the ground and two EBG structures near the feedline. By simply adjusting the dimensions of the two EBG structures, the centre frequencies of the notched bands can be allocated at 5.2 and 5.8 GHz, respectively. The UWB bandpass filter has been simulated, fabricated and measured, with good agreement between the simulated and measured results. The two notched bands of the BPF centred at 5.2 and 5.8 GHz have 10 dB fractional bandwidths of about 5.7 and 3.4 , respectively. View full abstract»

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  • X-band coplanar Wilkinson power divider based on GaAs MMIC technology

    Publication Year: 2011 , Page(s): 758 - 759
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (334 KB)  

    An X-band coplanar Wilkinson power divider based on GaAs MMIC technology is proposed. The power divider is designed at 10 GHz and simulated using HFSS, and simulated results show that it has reflection loss of less than -16.5 dB and insertion loss of less than -3.6 dB. Measured results show that the divider has reflection loss of less than -15.0 dB and insertion loss of less than -3.5 dB. Experimental results agree well with simulated results. View full abstract»

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  • High density vertical silicon NEM switches with CMOS-compatible fabrication

    Publication Year: 2011 , Page(s): 759 - 760
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    Presented is a resistive, vertically oriented, silicon electromechanical cantilever switch, fabricated with a two-mask top-down CMOS-compatible process. The fabricated switch has a vertical height of approximately 500 nm, a tip width of 35 nm, and an airgap of 30 nm between the cantilever and two lateral gates. Preliminary testing results show an initial pull-in voltage of 17 V with contact held by van der Waals forces even in the absence of actuation voltage. Subsequent switching occurs at 25 V. With low-cost fabrication and high integration density, the vertical nanoelectromechanical (NEM) switch is a promising candidate for memory and computing applications. View full abstract»

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  • Optical transmission performance in AMOOFDM downlink NG-PON systems using APD and pin receivers

    Publication Year: 2011 , Page(s): 761 - 762
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    Adaptively modulated optical orthogonal frequency division multiplexing (AMOOFDM) modulation is experimentally evaluated using different photodiodes. A comparison is made between positive-intrinsic-negative (pin) and avalanche photodiode (APD) receivers in next generation passive optical network (NG-PON) downlink architecture. Direct modulation in transmission as well as direct detection in reception allows reducing the cost of the system. The results are obtained respecting the requirements of a class B+ optical budget. An additional amplifier is implemented to increase the reach of the pin photodiode. Although having a narrower bandwidth, the APD offers better performance than the pin. A bit rate of 10 Gbit/s can be reached for a distance of 60km with an optical budget of 30dB and without any optical amplifier. View full abstract»

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  • RF-MEMS based tri-band GaN power amplifier

    Publication Year: 2011 , Page(s): 762 - 763
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (278 KB)  

    An RF-MEMs based tri-band GaN power amplifier with state-of-the-art performance is presented. The active device is a low-cost GaN-on-Si transistor with a plastic package. A dedicated broadband output matching network is designed to provide the desired waveform at the device intrinsic level. The frequency reconfigurability is implemented with one RF-MEMS at the input stage. Measured results show a 45, 28 and 46% power added efficiency (PAE) for an output power of 5.6, 3.0 and 4.5 W at 1.4, 2.5 and 3.6 GHz, respectively. Furthermore, the power amplifier exhibits a high drain efficiency of more than 46% across 1.3-1.4 and 3.4-3.7 GHz whilst delivering an output power of more than 4.3 W. View full abstract»

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  • Integrated MEMS-tunable VCSELs with high modulation bandwidth

    Publication Year: 2011 , Page(s): 764 - 765
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The modulation bandwidth of micromachined tunable VCSELs is typically limited by the parasitic capacitance associated with the large mesa platform for the movable mirror. Presented is a simple technology for wafer-scale integration of tunable VCSELs with low mesa capacitance and high modulation bandwidth. Small signal measurements show a 3dB bandwidth of up to 6 GHz over a tuning range of 18 nm. Digital modulation is demonstrated with error-free data transmission at 5 Gbit/s and eye diagrams at 10 Gbit/s. 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