Showing papers in "Electronics Letters in 2011"
TL;DR: In this paper, a bandwidth-enhanced microwave absorber using a double resonant metamaterial is presented, which has a thin configuration and its performance is constant for different polarisations.
Abstract: A bandwidth-enhanced microwave absorber using a double resonant metamaterial is presented. Its bandwidth is increased compared with previous metamaterial absorbers. The proposed absorber has a thin configuration and its performance is constant for different polarisations. Numerical and experimental results support the proposed absorber's performance.
188 citations
TL;DR: In this paper, it was shown that the non-crossing-type hysteretic loop cannot occur in ideal memristors, memcapacitors and meminductors which are defined axiomatically via the corresponding constitutive relations or via other equivalent characteristics.
Abstract: Recently, novel findings have been published, according to which some mem-systems excited by harmonic signals can be characterised by the so-called `non-crossing-type pinched hysteretic loops`. Presented is a proof that this phenomenon cannot occur in ideal memristors, memcapacitors and meminductors which are defined axiomatically via the corresponding constitutive relations or via other equivalent characteristics, and that the `crossing-type hysteretic loop` is thus one of their typical fingerprints.
132 citations
TL;DR: The exact closed-form expression for the outage probability of cognitive radio dual-hop amplify-and-forward relay networks is derived and readily enables evaluating the effect of primary users on the secondary system performance.
Abstract: The exact closed-form expression for the outage probability (OP) of cognitive radio dual-hop amplify-and-forward (AF) relay networks is derived. The tractable expression of the OP, given in the form of elementary functions, readily enables evaluating the effect of primary users on the secondary system performance. It has been shown that the use of AF relaying significantly improves the performance of cognitive radio networks compared to its direct transmission counterpart.
126 citations
TL;DR: In this paper, the Pareto distribution is used for low-grazing-angle high-resolution radar sea clutter returns and validation of it as a model for radar clutter is provided.
Abstract: Recently it was discovered that the Pareto distribution is a good model for low-grazing-angle high-resolution radar sea clutter returns. Validation of it as a model for high-grazing-angle radar clutter is provided.
118 citations
TL;DR: Circuit realisations of emulators transforming memristive devices into effective floating memcapacitive and meminductive systems are suggested.
Abstract: Suggested are circuit realisations of emulators transforming memristive devices into effective floating memcapacitive and meminductive systems. The emulator's circuits are based on second generation current conveyors and involve either four single-output or two dual-output current conveyors. The equations governing the resulting memcapactive and meminductive systems are presented.
113 citations
TL;DR: In this article, a planar inverted-F antenna (PIFA) incorporating a triangular Sierpinski gasket is presented, which shows dual-band response, combining a 16% band at 2.45 GHz with an upper 12 % band at 5.2 GHz.
Abstract: A novel planar inverted-F antenna (PIFA), incorporating a triangular Sierpinski gasket, is presented. The used conducting textile and polyester fleece allow easy on-body integration and simple practical fabrication. It shows dual-band response, combining a 16 % band at 2.45 GHz with an upper 12 % band at 5.2 GHz. The broadside gain is 3.1 dBi. Good agreement between calculated and measured data is observed.
105 citations
TL;DR: In this article, a simple on-off keying (OOK) predistortion scheme together with a simple first-order resistance-capacitance equalisation circuit was proposed to increase the modulation speed of a white-light high-brightness LED (HB-LED).
Abstract: In addition to the illumination purpose, using a light-emitting diode (LED) for indoor optical wireless communication has attracted much attention recently. Proposed and demonstrated is the use of a simple on-off keying (OOK) predistortion scheme together with a simple first-order resistance-capacitance equalisation circuit to increase the modulation speed of a white-light high-brightness LED (HB-LED). Optical filtering and complicated modulation formats are not required. Since only OOK modulation is used, the signal modulation and detection are very simple. Also are compared the different combinations of the system designs. By using first-order equalisation together with a predistortion, a bit-error rate of -10 -10 at 10 Mbit/s can be easily achieved when using the 1 MHz bandwidth phosphor-based white HB-LED.
104 citations
TL;DR: In this article, a 4-order quasi-elliptic filter is used to replace each quarter-wavelength transformer in a conventional Wilkinson power divider for good passband selectivity.
Abstract: A Wilkinson power divider with improved out-of-band rejection is proposed. A fourth-order quasi-elliptic filter is used to replace each quarter-wavelength transformer in a conventional Wilkinson power divider for good passband selectivity. Additional transmission zeroes are created by using the 0° feeding structure to enhance the out-of-band rejection. A 2 GHz Wilkinson power divider incorporating quasi-elliptic filters with a fractional bandwidth of 5% has been fabricated. The measured results present 40 dB roll-off skirts at 2 ± 0.12 GHz and validate the design concept.
97 citations
TL;DR: In this paper, the inscription of a fibre Bragg grating into a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer was presented, and the grating had a Bragg wavelength of 1569 nm and a temperature sensitivity of -36.5±0.3 pm/°C.
Abstract: A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg gratings: TOPAS has a much lower water affinity and has useful properties for biosensing. The grating had a Bragg wavelength of 1569 nm and a temperature sensitivity of -36.5±0.3 pm/°C.
96 citations
TL;DR: The proposed ESPRIT-based DOA estimation for the MIMO radar using reduced-dimension transformation has very close angle estimation performance to conventional ESPrIT; also it has slightly better performance than conventional ESPRit for low SNR.
Abstract: Direction of arrival (DOA) estimation for colocated multiple-input multiple-output (MIMO) radar is considered. An estimation of signal parameters via rotational invariance techniques (ESPRIT)-based DOA estimation for the MIMO radar using reduced-dimension transformation is proposed to reduce the complexity. The proposed algorithm has very close angle estimation performance to conventional ESPRIT; also it has slightly better performance than conventional ESPRIT for low SNR. Simulation results verify the usefulness of the proposed algorithm.
94 citations
TL;DR: In this paper, a double-sided printed compact antenna for UWB application is proposed, having a total size of 30×22 mm, consisting of a patch fed by a microstrip line and a partial ground plane.
Abstract: A double-sided printed compact antenna for UWB application is proposed. The proposed antenna, having a total size of 30×22 mm, consists of a patch fed by a microstrip line and a partial ground plane. The modified ground plane with triangular shaped slots on its top edge helps to increase the bandwidth of the proposed antenna. The double-sided printed antenna has a bandwidth (VSWR≤2) from 3.08 to 15.90 GHz and a maximum gain of 5.9 dBi. Antenna radiation patterns show stable variation within its operating band.
TL;DR: Experiments with the most representative FKP public database confirm that the SIFT features obtained after Gabor enhancement of the principal finger knuckle lines improve the performance of the person identifier.
Abstract: Presented is a new approach to person verification using finger-knuckle-prints (FKPs). It applies a Gabor filter to enhance the FKP information and a scale invariant feature transform (SIFT) to extract the features. Experiments with the most representative FKP public database confirm that the SIFT features obtained after Gabor enhancement of the principal finger knuckle lines improve the performance of the person identifier.
TL;DR: In this paper, a dual-band-notched ultra wideband (UWB) antenna is presented, which consists of a trapezoidal ground plane with a rectangle slot, a Y-shaped monopole used as the radiator, together with a modified complementary co-directional splitering resonator (SRR) etched on the radiation patch, leading to the desired dual notched bands for lower and upper bands of the WLAN.
Abstract: To prevent interference problems due to existing nearby communication systems within an ultra-wideband (UWB) operating frequency, a compact dual-band-notched UWB antenna is presented. This antenna consists of a trapezoidal ground plane with a rectangle slot, a Y-shaped monopole used as the radiator, together with a modified complementary co-directional splitering resonator (SRR) etched on the radiation patch, which leads to the desired dual notched bands for lower and upper bands of the WLAN. Experimental results show that the designed antenna, with compact size of 24×25×mm, has a wide bandwidth covering 3.05-14.2 GHz, realising dual notched bands of 5.14-5.36 and 5.74-6.07 GHz.
TL;DR: In this paper, the Ricean distribution was used to analyze the radio wave propagation in a high-speed railway cutting scenario, derived from 930 MHz measurements taken along the Zhengzhou-Xi'an high- speed railway of China.
Abstract: Presented is the statistical analysis of radio wave propagation in a high-speed railway cutting scenario, derived from 930 MHz measurements taken along the ‘Zhengzhou-Xi'an’ high-speed railway of China. The crown width and bottom width of the cutting are well-covered by the proposed models. The Ricean distribution offers a good fit and the K-factor is found to be lognormal, with a mean value of 1.88 dB and standard deviation of 3.29 dB.
TL;DR: In this paper, the modulation characteristics of vertical-cavity surface-emitting lasers with a buried tunnel junction emitting in the important wavelength regime around 1.55 m are presented.
Abstract: The modulation characteristics of vertical-cavity surface-emitting lasers with a buried tunnel junction emitting in the important wavelength regime around 1.55 m are presented. For the first time it was possible to demonstrate bit rates up to 40 Gbit/s also in this waveband. The 3 dB bandwidth measured under continuous-wave driving conditions was higher than 19 GHz. The present devices were found to be somehow sensitive to the bit-pattern length, especially at high temperatures or data rates resulting in some error-flooring. Error-free performance could be demonstrated up to 35 Gbit/s at room temperature and up to 25 Gbit/s at 55°C.
TL;DR: In this paper, an optically transparent microstrip patch mounted on the surface of a commercially available solar module is proposed, which comprises a thin sheet of clear polyester with a conductive coating.
Abstract: An optically transparent microstrip patch mounted on the surface of a commercially available solar module is proposed. The patch comprises a thin sheet of clear polyester with a conductive coating. The amorphous silicon solar cells in the module are used as both a photovoltaic generator and the antenna ground plane. The proposed structure provides a peak gain of 3.96 dBi in the 3.4-3.8 GHz range without significantly compromising the light transmission in the module. A comparison between copper and transparent conductors is made in terms of antenna and solar performance. The proposed technique is considerably simpler than previous integration approaches.
TL;DR: In this paper, a simple and successful design for matching complex impedance loads with different values at two different frequencies is presented, and the explicit closed-form equations for the transformer parameters are derived analytically.
Abstract: A simple and successful design for matching complex impedance loads with different values at two different frequencies is presented. The explicit closed-form equations for the transformer parameters are derived analytically. The validity of the proposed design is verified by a numerical example of designing the input matching network of an amplifier.
TL;DR: An improvement of a discrete cosine transform (DCT)-based method for electrocardiogram (ECG) compression is presented, showing very good results, confirming that the proposed strategy exhibits competitive performances compared with the most popular compressors used for ECG compression.
Abstract: An improvement of a discrete cosine transform (DCT)-based method for electrocardiogram (ECG) compression is presented. The appropriate use of a block based DCT associated to a uniform scalar dead zone quantiser and arithmetic coding show very good results, confirming that the proposed strategy exhibits competitive performances compared with the most popular compressors used for ECG compression.
TL;DR: In this article, an antenna-coupled field-effect transistors were integrated as multi-pixel (5×10) detector arrays for electromagnetic radiation between 550 and 600×GHz using commercial 0.15××m CMOS process technology.
Abstract: Antenna-coupled field-effect transistors were integrated as multi-pixel (5×10) detector arrays for electromagnetic radiation between 550 and 600×GHz using commercial 0.15××m CMOS process technology. Reported is a minimum optical noise-equivalent-power (NEP) of 43 pW/ √Hz and a maximum (capacitive-loading-limited) optical responsivity of 970 V / W (both values averaged). An electrical NEP of 9 pW / √Hz is estimated. Inter-chip variations are analysed with a set of 15 samples showing a low standard deviation of less than 8× for both responsivity and NEP at the optimum operation point. Intra-chip variation is low for non-edge pixels. Both the very good NEP values and the low variations indicate that a cost-efficient CMOS process is well suitable for reliable fabrication of multi-pixel terahertz focal plane arrays.
TL;DR: In this paper, a low power 3-10 GHz common-gate CMOS ultra wideband (UWB) low-noise amplifier (LNA) using a T-match input network and the self-body bias technique is demonstrated.
Abstract: A low-power 3–10 GHz common-gate CMOS ultra-wideband (UWB) low-noise amplifier (LNA) using a T-match input network and the self-body-bias technique is demonstrated Wideband input impedance matching was achieved by using the proposed T-match input network to improve the input matching at low frequencies A low supply voltage of 11 V (for two VDS drops) was achieved by using the self-body-bias technique to reduce the threshold voltage (Vth) of the transistors, which leads to a low power consumption (PD) At VG=077 V, the LNA consumed 215 mW and achieved S11 of −104 to −355 dB, S21 of 104 dB, and an average NF of 49 dB over the 3–10 GHz band of interest At VG=063 V, the LNA consumed 099 mW and achieved S11 of −107 to −358 dB, S21 of 79 dB and an average NF of 6 dB Both are the lowest PD ever reported for an UWB CMOS LNA with bandwidth greater than 6 GHz
TL;DR: Important aspects of wideband DRFM design on a printed circuit board are highighted and the architecture of the DRFM that was implemented using commercial-off-the-shelf components is presented.
Abstract: The test and evaluation of modern radars using hardware in the loop simulators requires the use of wideband high-fidelity, digital radio frequency memories (DRFM) in order to generate realistic target returns. Important aspects of wideband DRFM design on a printed circuit board are highighted and the architecture of the DRFM that was implemented using commercial-off-the-shelf components is presented. The spurious free dynamic range of the DRFM was characterised as -47 dBc worst case over an instantaneous bandwidth of 800-MHz. An experimental pulse-Doppler radar was used to compare the fidelity of the returns from the DRFM and an optical delay line.
TL;DR: In this article, a semi-circle-shaped aperture ultra wideband (UWB) antenna with triple band-notched characteristics is proposed, where the band notches are realized by etching one complementary split-ring resonator inside a circular exciting stub on the front side, employing a interrogation-shaped defected ground structure in each side of the ground plane as well as symmetrically adding a pair of open-circuit stubs at the edge of the slot.
Abstract: A novel semi-circle-shaped aperture ultra-wideband (UWB) antenna with triple band-notched characteristics is proposed The band notches are realised by etching one complementary split-ring resonator inside a circular exciting stub on the front side, employing a interrogation-shaped defected ground structure in each side of the ground plane as well as symmetrically adding a pair of open-circuit stubs at the edge of the slot, and tri-band rejected filtering properties in the WiMAX/WLAN are achieved Experimental results show that the designed antenna, with compact size of 24 × 30 × mm
2
, has an impedance bandwidth of 26 - 12 - GHz for VSWR less than 2, except three freqency stop-bands of 33 - 4, 515 - 54, and 58 - 61 - GHz Moreover, the antenna has good omnidirectional radiation patterns in the H-plane
TL;DR: A loop-type ground antenna formed by connecting a capacitor between two ground points is described in this article, where the resonant frequency of the ground loop is conveniently controlled by changing the capacitance.
Abstract: A loop-type ground antenna formed by connecting a capacitor between two ground points is described. The resonant frequency of the ground loop is conveniently controlled by changing the capacitance. The proposed loop-type radiator is excited by conventional shorting line loop feeding that may include an inductor. A loop type ground antenna is designed for Bluetooth and Wi-Fi applications.
TL;DR: In this paper, a simple technique based on the substrate end shaping was used to correct the tilted beams and low axial gains of balanced antipodal Vivaldi antennas, and the resulting antennas provided high axial gain, within a wide frequency band.
Abstract: Balanced antipodal Vivaldi antennas normally suffer from tilted beams and low axial gains. A simple technique, based on the substrate end shaping, is used to correct both problems. Consequently, the resulting antennas provide high axial gains, within a wide frequency band. Their performance is compared with the conventional Vivaldi antenna, and the improvements are discussed.
TL;DR: A new optically controlled reconfigurable antenna for cognitive radio is presented, which can operate at an ultra-wideband and three narrow bands by controlling four photoconductive switches.
Abstract: A new optically controlled reconfigurable antenna for cognitive radio is presented. The antenna can operate at an ultra-wideband and three narrow bands by controlling four photoconductive switches. The bandwidth of the ultra-wideband is 2.65 to 10.3 GHz. The bandwidths of three narrow bands are 7.10 to 8.01 GHZ, 3.55 to 5.18 GHz, and 5.12 to 6.59 GHz, respectively.
TL;DR: A vein pattern database collected by the authors and freely available for research purposes only is described and results obtained after segmentation with a local thresholding method and classification by using 2D correlation of images gathered in this database are presented.
Abstract: A vein pattern database collected by the authors and freely available for research purposes only is described. The results obtained after segmentation with a local thresholding method and classification by using 2D correlation of images gathered in this database are presented. Complete results are attached to the database as a reference for other researchers using it.
TL;DR: A computationally efficient method for multi-target localisation in bistatic MIMO radar that has lower computational complexity and gives better performance, particularly when the ratio of the product of transmitter and receiver array size to the number of targets is large.
Abstract: A computationally efficient method for multi-target localisation in bistatic MIMO radar is presented. The key idea is to apply the propagator method which requires only linear operation but does not involve any eigendecomposition of the sample covariance matrix. Compared with the ESPRIT method, it has lower computational complexity and gives better performance, particularly when the ratio of the product of transmitter and receiver array size to the number of targets is large. Simulation results are presented to verify the effectiveness of the proposed method.
TL;DR: In this paper, a new Y-junction four-way power divider is proposed by integrating the 90° Y-Junction SIW power dividers and the half-mode substrate integrated waveguide (HMSIW), which can be used in millimetre-wave and microwave circuits owing to its simple and novel structure.
Abstract: The substrate integrated waveguide (SIW) plays a very important role in millimetre-wave and microwave integrated circuits and systems with low return loss and high Q-factor. Also, the half-mode substrate integrated waveguide (HMSIW) has been developed in recent years. A new Y-junction four-way power divider is proposed by integrating the 90° Y-junction SIW power divider and HMSIW power divider. Simulated and measured results show that the return loss of the input port is below -15 dB over 8.6 to 12.2 GHz and transmissions are about -7.6 dB ± 0.2 dB in the passband. So, it makes the 6 dB power divider used preferably in a broad bandwidth. The new power divider can be produced in batches and can be widely used in millimetre-wave and microwave circuits owing to its simple and novel structure.
TL;DR: In this paper, a distributed feedback (DFB) laser diodes based on the concept of lateral metal gratings fabricated on type-I quantum well GaInAsSb/AlGaInSb material are presented.
Abstract: Distributed feedback (DFB) laser diodes based on the concept of lateral metal gratings fabricated on type-I quantum well GaInAsSb/AlGaInAsSb material are presented. Monomode emission in the 3.4 µm wavelength range was achieved for the first time for a GaSb based DFB laser diode. Excellent sidemode suppression ratios beyond 30 dB are demonstrated in combination with a modehop-free tuning range around 8.5 nm. Using a specially developed polymer-free DFB processing route allowing improved heat dissipation, laser operation in continuous-wave mode was observed at temperatures up to around 20°C.
TL;DR: In this paper, a dual-band MIMO antenna with high port isolation is proposed, which is basically composed of two folded monopoles and is designed to operate at 2.4/5.6 GHz.
Abstract: A compact dual-band MIMO antenna with high port isolation is proposed. The proposed antenna is basically composed of two folded monopoles and is designed to operate at 2.4/5.6 GHz. The high isolation is achieved by introducing two transmission lines on the top surface of the substrate and etching two slots on the ground. The measured isolation between the two monopoles is higher than 25 dB in both bands. The measured impedance bandwidths (|S
11
|<;-10dB) of the proposed antenna are 2.26-2.5 GHz and 5.41-5.79GHz, respectively. The predicted results are compared with the measured data and good agreement is found.