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Electronics Letters
Print ISSN
0013-5194
E-ISSN: 1350-911X
E-ISSN: 1350-911X
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Volume 48, Issue 10 , 10 May 2012
Volume 48, issue 10
10 May 2012
In Brief
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- Author(s): Junghwan Kim
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Professor Junghwan Kim from Sejong University in Korea talks about the research behind his Letter ‘High up-conversion gain optoelectronic mixer using uni-travelling carrier phototransistors’ page 583. - Author(s): H. Dyball
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A new class of RF switches have been developed by MIT Lincoln Laboratory in the US. The single chip high-performance vertically stacked switches are based on a wafer-scale 3D integration technology, and have a footprint that is much smaller than in conventional 2D switches. The approach, which is fully compatible with the standard Si CMOS process, could also be used for other types of circuit such as amplifiers, signal processors and imagers. - Author(s): J. Baldwin
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Researchers from the Tokyo Institute of Technology have demonstrated a direct modulation of the output power of a resonant tunnelling diode (RTD) oscillator and measured its frequency response in the THz frequency range. They have also achieved wireless data transmission at 542 GHz, the first report of wireless communication in this range.
Interview
Close to tiers
Intense resonance
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- Author(s): Hualei Wang; Hui Zhong; Yu Shi; Ken-Ya Hashimoto
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The passband width obtained in the SAW/BAW filter is inherently limited by the electromechanical coupling factor K2 of piezoelectric substrate. Proposed is a new design technology to flexibly control the passband width without sacrificing insertion loss, out-of-band rejection and steepness of the transition bands. A bandpass LC filter has been designed based on the traditional elliptic filter design. The LC resonators are replaced with SAW/BAW resonators in this filter and the design of the resonators is optimised to suppress passband ripples generated by finite capacitance ratio γ. It revealed that filters with different relative bandwidth are easy to design using one piezoelectric substrate. This technique is applied to the design of a SAW filter fabricated on the Cu-grating/15°YX-LiNbO3 structure.
Design of narrow bandwidth elliptic-type SAW/BAW filters
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- Author(s): J.P. Doane; K. Sertel; J.L. Volakis
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Maximum bandwidth limits are developed for lossless planar arrays over a ground plane through use of Fano's broadband impedance matching method and Richards’ transformation. It is demonstrated that such an array cannot exceed 8.3:1 bandwidth without material loading (for VSWR≤2). It is also demonstrated that an additional dielectric superstrate layer can provide up to 12.1:1 bandwidth, without magnetic or lossy substrates. A simple analytic expression for the maximum bandwidth is given as a function of impedance mismatch (VSWR) and substrate material parameters. The dependence of bandwidth on aperture complexity is quantified, showing that a simple first-order aperture has a bandwidth limit of 5:1, without material loading. - Author(s): J. Pourahmadazar; V. Rafii
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A new design of a broadband circularly polarised square slot antenna array (CPSSAA) fed by a symmetric coplanar waveguide (CPW) for L- and S-band applications is presented. The proposed antenna is composed of 2×2 CPSS antennas and a sequentially rotated feed network. In this model, compared with the previous CPSSAA with an asymmetric fed structure, the impedance bandwidth of the antenna is increased, and is 71% wider than the impedance bandwidth of a previous similar design. The designed antenna operates over the frequency band 1–4.34 GHz (4.34:1, 125%) for VSWR < 1.6 exhibiting a 120% (1.11–3.98 GHz, 3.58:1) circular polarisation bandwidth. The proposed CPSSAA can provide a peak gain of about 8.9 dBic at 3 GHz, with gain variations less than 1.5 dB at operating frequencies. Measured and simulated results validate the proposed design. - Author(s): C.-H. Lee; Y.-H. Chang; C.-E. Chiou
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Presented is a coplanar waveguide fed antenna for multi-band operation covering the digital video broadcasting signal reception in the UHF band, mobile communications in the GSM band, and the 2.4 GHz 802.11g/n band. The size of the designed antenna is 114×60 mm and it is printed on an FR4 substrate of thickness 0.8 mm with dielectric constant 4.4. It has an inner U-shaped strip enclosed by an outer loop strip and the outer loop strip is designed to obtain a wide operating bandwidth. Experimental results show that the proposed antenna exhibits a good impedance matching over a wide frequency range of 470 to 960 MHz, 1450 to 1880 MHz, and 2.4 to 2.6 GHz. - Author(s): L. da Silva Mello; M.S. Pontes; E. Couto de Miranda
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Measured data of rain attenuation from 19 terrestrial line-of-sight links, operating in frequencies from 14.5 to 83.5 GHz, were analysed to provide statistics of fade durations as a function of the attenuation threshold. From these results, an empirical method for predicting outage intensity owing to rain attenuation was derived, that shows good agreement with the measurements and allows the calculations of required link margins. - Author(s): Z.P. Wang; P.S. Hall; P. Gardner; J.H. Wu
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Prsented is a Yagi antenna with improved out-of-band gain suppression to reduced the demands on the front end band filter. Two parasitics close to the fed element are used to increase the Q-factor of that element, and the length and position of the other directors and reflectors are optimised to suppress the out-of-band gain. Simulated and measured results show that the proposed antenna has the characteristics of a conventional Yagi antenna in the passband, albeit with a narrower bandwidth, whilst providing more than 10 dB of gain suppression to interference signals located outside the band.
Bandwidth limits for lossless planar arrays over ground plane
Broadband circularly polarised slot antenna array for L- and S-band applications
Design of multi-band CPW-fed antenna for triple-frequency operation
Measurements and prediction of outage intensity owing to rain attenuation
Yagi antenna with improved out-of-band gain suppression
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- Author(s): Y. Liu; A. Al-Ahdal; P. Georgiou; C. Toumazou
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Proposed is an ISFET readout scheme with minimum analogue components to minimise parasitic and noise effects in large-scale chemical sensing arrays. For each array pixel, a pair of complementary ISFETs shares the same floating gate in an inverter configuration. An additional electrical input is capacitively coupled to the same floating gate with a periodic reference signal input. In this way, the conventional ISFET analogue output is replaced by a chemically controlled pulse width modulated signal. Theoretical analysis and experimental results show a pulse width pH sensitivity of around 6%, of the input reference signal period, per pH. This is achieved along with ±1 V offset suppressing capability. - Author(s): A. AlAhdal; C. Toumazou
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Ion sensitive field effect transistors (ISFETs) are pH sensors that have generally been used in the analogue domain. It is possible to use them in the digital domain for chemical thresholding applications. To facilitate small pH change detection where a simple switch suffers from ripple and distorted output, a chemical switch with input noise immunity is needed. Reported are first measurements of an ISFET-based chemical Schmitt trigger. It provides a more stable output with better noise immunity. It can be used in applications where the digital detection of small pH changes is required. - Author(s): K. Sooksood; M. Ortmanns
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In implantable stimulators, a current-controlled stimulation is preferred over a voltage-controlled one due to its safety. However, the power efficiency is a major disadvantage. By reducing the headroom voltage needed in the current driver, power efficiency of a constant current stimulation is improved. A promising technique is to bias the transistor in the triode region whereby improving output impedance through the regulated cascode structure. This comes with a feature of an implicit compliance monitor. Proposed is a new power efficient high compliance output stage.
Minimal readout scheme for ISFET sensing arrays based on pulse width modulation
ISFET-based chemical Schmitt trigger
Power efficient output stage for high density implantable stimulators
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- Author(s): Y. Chen; P.-I. Mak; L. Zhang; Y. Wang
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A highly-transistorised bandpass filter (BPF) using a source-follower-based (SFB) resonator is proposed. It benefits from the advantageous properties of the source follower (e.g. no parasitic pole, linear VGS I/O relationship, high-input and low-output impedances), while combining it with a compact and low-power grounded differential active inductor to synthesise the complex poles. Fabricated in 90 nm CMOS, a fourth-order 75 MHz-IF BPF prototype merging two such SFB resonators measures a 10 MHz bandwidth at 2 mW of power. The die size is merely 0.07 mm2. - Author(s): Dong-Hyun Kim; Jae-Sung Rieh
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A 138 GHz down-conversion mixer with a branch-line coupler has been developed based on a 90 nm CMOS technology. The fabricated mixer shows a differential conversion gain of 3.7 dB with the mixer core drawing a current 0.66 mA from a 1.2 V supply. The 1 dB gain compression point is estimated to be larger than −6 dBm. The mixer occupies 0.61 × 0.62 mm2 of chip area excluding pads. - Author(s): A. Dasu; S. Chandrasekaran
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The dynamic thermal management problem is posed for multi-processing element (multi-PE) computing systems (which can support both dynamic re-parallelisation of tasks across PEs and their operating frequencies) as a multi-constraint optimisation problem. Proposed is a cellular nonlinear network controller as an online solver of this problem. Results obtained through a simulation model are presented followed by a brief overview of pertinent literature. - Author(s): Y. Jung; S. Lee; C.-H. Chen; G.C. Temes
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A novel ΔΣ analogue-to-digital (ADC) architecture is proposed for second-order noise shaping enhancement. The new architecture is less dependent on the opamp DC gain than the earlier ΔΣ ADC with second-order noise shaping enhancement. Also, the proposed architecture reduces the complexity of the clock generator and zero optimisation compared to the earlier one. A ΔΣ ADC using the new configuration was designed and simulated. The results verify the advantages of the proposed structure. - Author(s): J. Cadenas; G.M. Megson; R.S. Sherratt; P. Huerta
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The ever increasing demand for high image quality requires fast and efficient methods for noise reduction. The best-known order-statistics filter is the median filter. A method is presented to calculate the median on a set of NW-bit integers in W/B time steps. Blocks containing B-bit slices are used to find B-bits of the median; using a novel quantum-like representation allowing the median to be computed in an accelerated manner compared to the best-known method (W time steps). The general method allows a variety of designs to be synthesised systematically. A further novel architecture to calculate the median for a moving set of N integers is also discussed. - Author(s): D.-K.G. Pham; P. Desgreys; P. Loumeau; T. Ridgers
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A new sigma-delta modulator (ΣΔM) architecture is proposed to digitise wideband distorted signals. It combines frequency band decomposition with bandpass (BP) ΣΔ converters and cascaded architectures. The novelties are the use of the residual signal transfer function at the output of the first summing node in a classical BP ΣΔ that is an almost free signal shaping in the ΣΔM and the digitisation of the shaped noise in order to cancel it out in a particular band. - Author(s): A.N.M. Alahmadi; G. Russell; A. Yakovlev
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Time difference amplification is a technique which has been developed previously to facilitate the measurement of temporal events in circuits whose magnitudes are decreasing with the advances in technology. A technique is proposed which extends the time input difference (ΔTinput) range achieved by current methods from 40 to 70 ps.
0.07 mm2, 2 mW, 75 MHz-IF, fourth-order BPF using source-follower-based resonator in 90 nm CMOS
CMOS 138 GHz low-power active mixer with branch-line coupler
Cellular nonlinear network controller for dynamic thermal management
Double noise coupling ΔΣ analogue-to-digital converter
Fast median calculation method
Multi-stage noise band cancellation ΣΔ modulator for digitisation of distorted signals
Time difference amplifier design with improved performance parameters
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- Author(s): S.Y. An; L.K. Lee; S.Y. Oh
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An angular radial partitioning (ARP) method divides an edge image into M×N partitions in order to make its compact image descriptor. However, it inherently suffers from a boundary problem that arises when edge pixels exist near the partition boundaries. Proposed is a modified ARP (mARP) to reduce degradation of retrieval performance caused by the boundary problem. For comparison, image retrieval tests have been carried out using the above two methods. The results demonstrate that the retrieval performance of the mARP is almost twice as good as that of the original one.
Modified angular radial partitioning for edge image description in image retrieval
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- Author(s): J.P. Murphy
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True random number generation is crucial in cyber-security applications. Proposed is a voltage-controlled true random number generator that is inherently field-programmable. This facilitates increased entropy as a randomness source because there is more than one configuration state which lends itself to more compact and low-power architectures. It is evaluated through electrical characterisation and statistically through industry-standard randomness tests. To the best of the author's knowledge, it is one of the most efficient designs to date with respect to hardware design metrics. - Author(s): M. Allegue-Martínez; M.J. Madero-Ayora; J.G. Doblado; C. Crespo-Cadenas; J. Reina-Tosina; V. Baena
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The efficient transmission and nonlinear modelling of orthogonal frequency division multiplexing (OFDM) signals are difficult to address owing to the special characteristics of this modulation scheme. Proposed is a digital predistortion technique suitable for the implementation in an OFDM transmitter to optimise the in-band interference caused by the nonlinear distortion generated in the amplification chain. The approach is experimentally validated by its application in one of the world's most advanced broadcasting systems, achieving an outstanding linearisation performance in the transmitter; specially for the in-band interference, a modulation error ratio (MER) of 42.1 dB is obtained. - Author(s): T. Maertens; H. Bruneel; J. Walraevens
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Priority scheduling is the most viable way to implement QoS differentiation in telecommunication networks. Most studies on priority scheduling do not take into account possible class clustering. In particular, they assume that different classes occur randomly and independently in the arrival stream of packets. In reality, however, packets of the same class may have the tendency to arrive in clusters. By using existing results, it is shown that class clustering may have a severe impact on the achievable delay differentiation in priority scheduling.
Field-programmable true random number generator
Digital predistortion technique with in-band interference optimisation applied to DVB-T2
Effect of class clustering on delay differentiation in priority scheduling
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- Author(s): Qinfen Xu; Xiaojun Bi; Guoan Wu
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The design of an ultra-compacted silicon-based bandpass filter in the sub-terahertz frequency range is explored. A filter with combline topology consisting of multilayered resonators and a cross-coupling capacitor has been designed in 0.13 µm SiGe. The dimensions of the implemented filter are 40×130 µm2, which are even smaller than a ground–signal–ground probing pad with 100 µm pitch. Meanwhile, the filter achieves a 3 dB bandwidth of about 32.0 GHz (22.0%) and an insertion loss of −7.7 dB at the centre frequency of 143 GHz. - Author(s): J.N. Hui; W.J. Feng; W.Q. Che
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A compact multilayer substrate integrated waveguide (SIW) balun bandpass filter is proposed. A 180° reverse phase characteristic between the input/output ports can be easily achieved by the middle metal-ground of the SIW power divider. Four inductive posts are added to the multilayer SIW power divider to realise a passband. Good in-band balance performance (amplitude and phase imbalance are less than 0.35 dB and 2°) over the passband are achieved for the balun bandpass filter. - Author(s): M. Hayati; L. Noori; A. Adinehvand
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A compact and low insertion loss microstrip filter, designed and fabricated using the open loop resonator to achieve a dual-band bandpass response with controllable centre frequencies, is presented. The coupling structures, consisting of three coupled lines with different widths, are used to control resonance frequencies that lead to the creation of two passbands at 2.4 and 5.2 GHz for wireless LANs application. In the design process, the admittance and impedance of the input are used to adjust the resonance frequencies for even and odd modes. Good agreement between the simulation and measurement results is achieved. - Author(s): Li Min-hua; Yang He-lin; Lin Hai; Xiao Bo-xun
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A compact dual-band band-reject filter using complementary split-ring resonators is proposed. This complementary structure helps to expand the bandwidth or to design filters with multi bands. The centre frequency of the filter is at 6.05 and 7.14 GHz with the FBW of 11.1 and 11.3%, respectively. Good agreement has been obtained between simulated and measured results. - Author(s): Z. Chen; W. Hong; J.X. Chen
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A low-cost planar active resonator in Ku-band based on the substrate integrated waveguide (SIW) technique is reported. A series feedback network is used to generate the negative resistance, which compensates the energy loss within the SIW cavity. The quality (Q) factor of the SIW resonator is greatly improved. An experimental active SIW reflective-resonator is designed and fabricated. The measured results show that the proposed active resonator possesses a loaded Q factor of 1455, and unloaded Q factor of 7631, which is ultra-high among other planar resonators. The active SIW resonator is a promising element for the design of high-performance microwave filters and oscillators. - Author(s): Z.B. Zhu; X.Q. Lin; J.Y. Jin; Y. Jiang; Y. Fan
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A novel modified split ring resonator (MSRR) cell with compact dimension, wide stopband and deep transmission zeros is proposed. A relative experimental formula is induced. Then, a novel lowpass filter is designed by cascading three MSRR cells. Large rejection through the entire W-band is obtained by carefully choosing three transmission zeros of MSRRs in the lower, the middle and the higher frequencies, respectively. A rejection level of more than 35.89 dB is achieved from 75 to 110 GHz. In contrast, a high-low impedance lowpass filter is optimally designed with similar dimensions, the largest rejection of which is only 23.56 dB. It is even less than the least rejection level of our proposed filter. - Author(s): D.S. Prinsloo; P. Meyer
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A measurement procedure to de-embed the noise figure (NF) of a three-port differential low-noise amplifier (LNA) from single-ended (SE) measurements is presented. An approximate solution for the differential NF is found in terms of two SE noise figure and gain measurements and the sensitivity of the de-embedded NF to unsymmetrical performance is analysed. The theory presented is applied to a three-port differential LNA and the de-embedded NF is compared to that of an equivalent SE LNA design. - Author(s): A.D. Alwakil; A.M.E. Safwat
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p.
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An analytical coupled-line based model is proposed for arbitrary double split ring resonator configurations. The model is verified by designing a slow-wave based Butterworth lowpass filter. The filter has been fabricated and measured. The measurements are in a good agreement with theoretical results over a wide frequency range.
Ultra-compacted sub-terahertz bandpass filter in 0.13 µm SiGe
Balun bandpass filter based on multilayer substrate integrated waveguide power divider
Compact dual-band bandpass filter using open loop resonator for multimode WLANs
Compact dual-band band-reject filter using complementary split-ring resonators
High-Q planar active resonator based on substrate integrated waveguide technique
Lowpass filter with large rejection through the entire W-band
Noise figure measurement of three-port differential low-noise amplifiers
Simple CAD model for direct coupled double split ring resonators
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- Author(s): K. Ishigaki; M. Shiraishi; S. Suzuki; M. Asada; N. Nishiyama; S. Arai
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p.
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Direct intensity modulation and wireless data transmission characteristics of terahertz-oscillating resonant tunnelling diodes (RTDs) is reported. A direct intensity modulation of the RTD oscillators was demonstrated, and the frequency response was measured. It was found that the 3 dB cutoff modulation frequency was limited by the parasitic elements of the external circuit, and increased up to 4.5 GHz by reducing such parasitic elements. Wireless data transmission by direct amplitude shift keying was demonstrated using an RTD oscillating at 542 GHz with cutoff frequency of 1.1 GHz. The BERs for bit rates of 2 and 3 Gbit/s were found to be 2×10−8 and 3×10−5, respectively. - Author(s): Junghwan Kim; S. Kanakaraju; W.B. Johnson; Chi H. Lee
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p.
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The optoelectronic mixing performance of a uni-travelling carrier heterojunction phototransistor (UTC-HPT) was compared with its performance as a photodiode (PD). The upconverted output power in HPT mode was 24 dBm higher than in PD mode. - Author(s): Y.W. Xu; A. Michael; C.Y. Kwok; T. Puzzer; G.D. Peng
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p.
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Reported is the integration of 1D planar silica graded index (GRIN) lenses in a 3D optical interconnect system to reduce free-space propagation loss. The 3D optical interconnect system consists of a pair of facing-up and facing-down 45° micro-mirrors that establish a vertical optical transmission path between stacked dies. Without the silica lens, experimental measurement shows optical power loss of 33.7dB. A pair of GRIN lenses is then integrated into the system. Optical test shows that the system performance is improved by more than 25dB. - Author(s): J. Hofrichter; T. Morf; A. La Porta; B.J. Offrein; P. Mechet; G. Morthier; T. De Vries; H.J.S. Dorren; O. Raz
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p.
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Reported is the inverting and non-inverting operation of indium phosphide (InP)-based microdisc modulators heterogeneously integrated on a silicon-on-insulator waveguide. The light transmitted through the waveguide can be modulated in an inverting and non-inverting manner depending on the bias conditions. Static extinction ratios and dynamic operation of the device up to 2.5 Gbit/s are demonstrated. Clean open eyes with extinction ratios better than 6 dB are shown and operation with a bit error rate below 1×10−10 is demonstrated at 1.0 Gbit/s for both operation modes with a bias of only 1 Vpp. - Author(s): M. Scheller; T.-L. Wang; B. Kunert; W. Stolz; S.W. Koch; J.V. Moloney
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A quantum-well vertical-external-cavity surface-emitting laser in combination with a quantum-well SESAM is used to generate femtosecond pulses. The passively modelocked VECSEL operates at room temperature emitting an average output power of 5.1 W at 1030 nm. At a repetition rate of 1.71 GHz, the 682 fs pulses are nearly transform limited. - Author(s): M. Zavvari; V. Ahmadi; A. Mir; E. Darabi
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A novel intersubband quantum dot photodetector is proposed and theoretically investigated. The presented device is based on the integration of a multiplication layer with a quantum dot infrared photodetector to increase generated photocurrent and enhance performance characteristics. To keep the dark current at lower values, resonant tunnelling barriers are used in absorption layers and designed so that there is photocurrent at a specific resonant wavelength. Numerical simulations show a higher responsivity of approximately 12 A/W and higher specific detectivity of approximately 6×109 cm.Hz1/2/W at λ=11 µm. - Author(s): D.F. Siriani; K.D. Choquette
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Coherent laser arrays designed using resonant optical waveguides (ROWs) have proven to offer one of the most promising methods of monolithic beam combining in diode lasers. However, the high lateral transmission that provides strong optical coupling also leads to increased loss – a detriment to laser efficiency and performance. Presented is a derivation of additional design rules to eliminate lateral radiation loss from ROW arrays while still maintaining all the strong coupling properties. Additionally, it is speculated that improved mode discrimination and enhanced field uniformity should result from the proposed design modifications. - Author(s): J. Palací; A. Bockelt; B. Vidal
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All-fibre control of a terahertz time-domain spectroscopy system based on photoconductive antennas fed with optical sources in the telecom band is demonstrated. A semiconductor optical amplifier (SOA) is used to obtain continuously tunable delays on 100 fs optical pulses. Additionally, the modulation required to carry out lock-in detection can be simultaneously performed avoiding mechanical choppers or high-voltage alternate biasing of the transmitter antenna.
Direct intensity modulation and wireless data transmission characteristics of terahertz-oscillating resonant tunnelling diodes
High upconversion gain optoelectronic mixer using uni-travelling carrier phototransistors
Integration of 1D planar silica GRIN lenses in 3D optical interconnect system
Inverting and non-inverting operation of InP microdisc modulators
Passively modelocked VECSEL emitting 682 fs pulses with 5.1 W of average output power
Quantum dot infrared photodetector enhanced by avalanche multiplication
Reduced loss and improved mode discrimination in resonant optical waveguide arrays
SOA-based optical processing for terahertz time-domain spectroscopy
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- Author(s): X.-Y. Wang; W.-D. Yu; X.-Y. Qi; Y. Liu
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In this reported work, radio frequency interferences (RFI) in synthetic aperture radar (SAR) are suppressed using novel tools. Introduced first are the random sampling techniques that are commonly used in large-scale machine learning areas to obtain the RFI subspace via the approximated spectral decomposition. Thus, one can reconstruct the RFI signals efficiently and then remove them from the original received SAR pulses one by one. The performance of the algorithm was tested on a P-band real dataset. - Author(s): M. Yang; G. Zhang
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A new methodology for speckle suppression of SAR images using an over-complete dictionary is presented. The approach taken is based on sparse and redundant representations by employing a combined dictionary consisting of wavelets, shearlets and learned dictionaries. Wavelets provide sparse expansions for point-like structures, shearlets provide sparse expansions for curve-like structures, and learning dictionaries are taken as obtaining the best performance on a training set. The experimental results demonstrate that the proposed algorithm provides more effective speckle reduction as well as detail preservation.
RFI suppression in SAR based on approximated spectral decomposition algorithm
SAR image despeckling using over-complete dictionary
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- Author(s): C.L. Chen; C.K. Chen; D.-R. Yost; J.M. Knecht
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Vertically stacked RF switches implemented by wafer-scale three-dimensional (3D) integration of three completely fabricated silicon-on-insulator wafers are demonstrated. The individual switch performance was maintained through the 3D integration process while the signal path is shortened by vertical interconnects. The footprint of the switch can be shrunk in proportion to the number of tiers it is distributed between, demonstrating the potential of significant size reduction of multiple-throw switches commonly required in many applications.
Vertically stacked RF switches by wafer-scale three-dimensional integration
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- Author(s): Lin Bai; Chen Chen; Jinho Choi
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p.
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–600
(3)
The partial maximum a posteriori probability (MAP) principle allows a decision on the list length of the list-based MIMO detection at a certain SNR to provide near optimal performance. The computationally efficient lattice reduction (LR) is adopted with the partial MAP-based list detection, where the column reordering criterion (CRC) is carried out to further reduce the list length and complexity.
Partial MAP-based lattice reduction-aided list MIMO detection
