Electronics Letters

A new design methodology is presented for outputting digital information from asynchronous analogue circuits, which allows signed frequency encoded signal transfer along a single channel. The circuit outputs data as a series of rate and pulse-width encoded spikes: pulsewidth modulation is used to represent vector and pulse frequency modulation is used to represent magnitude symbiotically. This technique can be used to increase the bandwidth of multiplexed neural signals, such as for address event registration, or by using a time-tofirst-spike system, to multiplex signals on a single channel. Additionally, feedback has been used to improve the switching speed of current starved inverters, reducing their power consumption by over an order of magnitude.

A report is presented on an erbium-ytterbium doped waveguide amplifier fabricated by Ag-Na ion-exchange in a commercial phosphate glass substrate. The 31 mm-long active waveguide provides a maximum internal gain of 5.3 dB=cm at 1534 nm. The amplifier was fully characterised in terms of gain spectrum, noise figure, pump efficiency and gain saturation.

Fig. 1 are considered here. Fig. l a depicts the basic flip-chip structure under investigation, a back-to-back structure with a coplanar thru line on the chip. The distinctive feature of the modified structure shown in Fig. lb is the compensation area located on the motherboard at the bump interconnect (compensation length 8 5~). This short line section of high characteristic impedance acts as an inductive counterpart, compensating the primarily capacitive behaviour of the bump interconnect [4]. It is referred to as the high-impedance compensation in the following. The test chips were flip-chip bonded to a ceramics motherboard at the Alcatel Research Center in Stuttgart, Germany. 0 1 20 40 60 00 designing and S. Knigge for fabricating the GaAs test wafers, A. Gutu-Nelle, M. Worbs and K. Hagele for preparing the flip-chip test assemblies and R. Doemer for performing the network analyser measurements.

A novel analogue CMOS circuit is presented which performs the arithmetical squaring of a voltage, using the square-law characteristic of the MOS transistor in saturation. The core circuit is constructed from four identical building blocks, which are connected so as to eliminate all unwanted offset terms. Simulation results from HSPICE are presented where the circuit is used for doubling the frequency of a sinusoidal input.

A low dark current CMOS image sensor (CIS) pixel without any process modification is developed. Dark current is mainly generated at the interface region of shallow trench isolation (STI) structure. Proposed pixel reduces the dark current effectively by separating the STI region from the photodiode junction using simple layout modification. Test sensor array that has both proposed and conventional pixels is fabricated using 0.18 m CMOS process and the characteristics of the sensor are measured. The result shows that the dark current of the proposed pixel is 0.93fA/pixel that is two times lower than the conventional design.

The paper describes a simple deterministic synthesis method for the design of aperiodic planar arrays with elements arranged on circular or elliptical rings. Differently from other techniques presented in the literature, both the number of elements per ring as well as the rings' spacing are synthesized adopting only a deterministic procedure which permits guarantying the best agreement (in terms of least mean square error) with respect to a circularly (or elliptically) symmetric reference pattern. Linear Aperiodic Arrays Synthesis: Recently a deterministic technique for the synthesis of linear aperiodic arrays with a given number of elements and an assigned amplitude excitation has been introduced [1-2]. In this paper the deterministic procedure presented in [2] for the design of linear sparse arrays is extended to the case of planar circular and elliptical arrays. The method introduced in [2] allows approximating a desired radiation pattern    F , generated by a linear source with continuous amplitude taper   i x , with the array factor

This paper presents a very fast CMOS glitch detector which has been designed to perform measurements on crosstalk between metal lines directly on silicon dies. Theoretical detection capability is better than 200 mV for 60 ps. A prototype has been implemented and successfully tested.

The energy consumption of high-speed optical signal processing circuits using optical and electronic components is compared. Integrated nonlinear optical circuits consume more energy than CMOS ICs with O=E and E=O converters in all but the very simplest of circuits. It is concluded that future generations of high-performance electronics will be the technology of choice for optical signal processing.

In this letter we present a new architecture for a polar decoder using a reduced complexity successive cancellation decoding algorithm. This novel fully-unrolled, deeply-pipelined architecture is capable of achieving a coded throughput of over 237 Gbps for a (1024,512) polar code implemented using an FPGA. This decoder is two orders of magnitude faster than state-of-the-art polar decoders.

First results from a study on tunable frequency-selective surfaces (FSSs) used for beam-steering applications are reported. In particular, the scattering response of a multilayer passband FSS based on varactorloaded rectangular slots has been investigated. Simulated and measured results show that tunable FSSs can be employed to locally control the phase of the transmitted field with limited amplitude losses.

A wideband perforated dielectric resonator antenna (PDRA) is presented. The effective permittivity of the dielectric resonator is altered by drilling holes into a circular ring lattice inside the DRA. The PDRA is equivalent of having an annular ring with lower permittivity outside the cylindrical disk, resulting in enhanced impedance bandwidth. The measured bandwidth of a prototype PDRA with relative permittivity 10.2 is 26.7% (S 11 < À10 dB).

External noise sources such as movement artefact may interfere with mechanomyography (MMG) signal recording, compromising signal detection for electrically-powered prosthesis control. A novel coupled microphone-accelerometer sensor pair, intended to facilitate noise reduction, was designed and tested on a below-elbow amputee. Sample recordings demonstrate clear distinction between motion artefact and useful MMG signals.

A simple method is reported for fabrication of AlN/GaN MOS-HEMTs. Ultra-thin Al 2 O 3 , which is formed using thermal oxidation of evaporated Al, was used for surface passivation and as a gate dielectric. Prior to formation of Al 2 O 3 , the Al protects the very sensitive AlN epilayer from exposure to processing liquid chemicals. Fabricated two-finger AlN/GaN MOS-HEMTs with 3 mm gate length and 200 mm gate width showed good gate control of drain currents up to a gate bias of 3 V and achieved a maximum drain current, I DSmax , of 900 mA/ mm. The peak extrinsic transconductance, G max , of the device is 100 mS/mm at V DS ¼ 8 V. Capacitance-voltage (C-V ) characteristics of Al 2 O 3 /AlN/GaN circular test MOS structures were observed and measured. They exhibited no hysteresis, indicating the good quality of the thermally grown Al 2 O 3 for realising AlN/GaN MOS-HEMTs for high power and high frequency applications.

Cancer affects a significant percentage of people, and early detection techniques are important for prompt and effective treatment. The use of microwave frequencies to achieve non-invasive and non-destructive cancer detections is currently under investigation by several research groups. In this frequency range, the dielectric properties of the biological tissue determine the interactions of the tissue with electromagnetic fields. Knowledge of the dielectric properties of both the normal and the malignant human tissues is therefore a fundamental starting point. A dielectric spectroscopy system, based on the use of a reflectometry setup, was used to perform an extensive experimental campaign on fresh surgical specimens. The measurement system allowed achieving a broadband dielectric characterisation of biological tissues up to 50 GHz, thus including millmetre-wave (mm-wave) frequencies. In the case of breast tissues, the results showed that the malignant and normal tissues exhibit significantly different complex dielectric permittivities of up to 50 GHz, due to their respective high and low water content. This permittivity difference is well detectable, and this paves the way to new screening methods based on mm-wave imaging systems.

Ex-facet, free-running low linewidth (~100 kHz), single mode laser emission is demonstrated using low cost, regrowth-free ridge waveguide Discrete Mode Fabry Pérot laser diode chips. These narrow linewidths are obtained from sub mW emission powers and above.

The present study explored the developmental changes of teacher–student interpersonal relationships as well as that of academic motivation among first-grade secondary school students. In addition, the link between teacher–student interpersonal behaviour and academic motivation across the school year was investigated. The data were collected 5 times within a school year, from 566 students of 20 mathematics and English classes, from 3 secondary schools in The Netherlands. Multilevel growth curve modelling was applied. Analysis of within-year changes in teacher–student interpersonal relationships revealed that the quality of relationships decreased over time. The decrease was more pronounced for Proximity than for Influence. Moreover, students' controlled motivation increased slightly, while autonomous motivation decreased systematically over time. Teacher–student interpersonal relationships are significant predictors of autonomous motivation. Several determinants like subject taught, class type, teacher gender, and student gender can explain differences in developmental trajectories of both interpersonal behaviour and academic motivation over time.

A new chaotic jerk circuit is realised using a current-tunable technique. Based on traditional nonlinearity of a signum function, newly smooth transitions from a balanced double-scroll chaotic jerk attractor to an unbalanced double-scroll and eventually to either a left-half or a righthalf single-scroll chaotic jerk attractor are experimentally revealed using either a negative or a positive adjustable current source I 0 , respectively. Current-tunable bifurcations are demonstrated. A plot of the largest Lyapunov exponent resembles a symmetrically balanced image centred at I 0 = 0.

Background. Research has shown that the teacher-student interpersonal relationship (TSIR) is important for student motivation. Although TSIR has received a growing interest, there are only few studies that focus on changes and links between TSIR and student academic motivation in a longitudinal fashion in non-Western contexts.

High-resistivity polycrystalline silicon (HRPS) is presented as a novel low-cost and low-loss substrate for radio-frequency (RF) passive components in wafer-level packaging and integrated passive networks. A record quality factor (Q ¼ 11; 1 GHz; 34 nH) and very low loss (0.65 dB=cm; 17 GHz) are demonstrated for inductors and coplanar waveguides, respectively, on HRPS.

Background. Research has shown that the teacher-student interpersonal relationship (TSIR) is important for student motivation. Although TSIR has received a growing interest, there are only few studies that focus on changes and links between TSIR and student academic motivation in a longitudinal fashion in non-Western contexts.

A novel leaky-wave antenna is demonstrated and developed at Ka-band in this work based on the newly proposed half-mode substrate integrated waveguide (HWSIW). This antenna is accurately simulated by using a full-wave electromagnetic simulator and then fabricated through a single-layer printed circuit board (PCB) process. Wide bandwidth and a quasi-omnidirectional radiation pattern are obtained. The proposed antenna is therefore a good candidate for millimeter-wave applications. Measured results are in good agreement with simulated results. Index Terms-Half-mode substrate integrated waveguide (HMSIW), leaky-wave antenna (LWA), millimeter-wave antenna, quasi-omnidirectional radiation pattern.

A simple right-angle transition between a rectangular waveguide (RWG) and a substrate integrated waveguide (SIW) is proposed. Two slots etched on the broad wall of the SIW are used to couple the waveguides. To obtain a wide bandwidth of operation the slots have different lengths to create a double resonance behaviour. The proposed component has a simple mechanical configuration with the flange of the standard RWG flush-mounted to the substrate of the SIW. A sample transition is designed to work in the lower part of the Ka-band. The experimental results agree well with numerical predictions. The proposed component has 6.6% bandwidth and insertion loss below 0.5 dB.

A Compact coplanar waveguide (CPW) fed ultrawideband (UWB) antenna is presented. The antenna consists of a corrugated half circular disc radiator and a notched CPW ground plane which are used to improve the impedance bandwidth and also to reduce the overall size to only 0.22 × 0.22 λ 2 at 3GHz. The calculated impedance bandwidth of the proposed antenna ranges from 3.5GHz to 11GHz for a reflection coefficient (S 11 ) less than -10dB. The proposed antenna has a relatively stable radiation patterns over its whole frequency band of interest. A U-shaped slot is embedded to obtain the bandnotched characteristic in the 5.0-6.0 GHz wireless local area network (WLAN) band.

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

The present study explored the developmental changes of teacher–student interpersonal relationships as well as that of academic motivation among first-grade secondary school students. In addition, the link between teacher–student interpersonal behaviour and academic motivation across the school year was investigated. The data were collected 5 times within a school year, from 566 students of 20 mathematics and English classes, from 3 secondary schools in The Netherlands. Multilevel growth curve modelling was applied. Analysis of within-year changes in teacher–student interpersonal relationships revealed that the quality of relationships decreased over time. The decrease was more pronounced for Proximity than for Influence. Moreover, students' controlled motivation increased slightly, while autonomous motivation decreased systematically over time. Teacher–student interpersonal relationships are significant predictors of autonomous motivation. Several determinants like subject taught, class type, teacher gender, and student gender can explain differences in developmental trajectories of both interpersonal behaviour and academic motivation over time.

A filter-based technique to extract the four parameters that characterise a single-dispersion Cole-Cole impedance model without direct measurement of the impedance real and imaginary parts is reported. Experimental results in the range 100 Hz-5 MHz using apples, apricots and kiwi fruits are given and results are compared with numerical simulations of the acquired model.

Craven, M.P., Hayes-Gill B.R., Curtis K.M. Two quadrant analogue squarer circuit based on MOS square-law characteristic. Electronics Letters (1991), 27(25): 2307-2308 http://dx.ABSTRACT: A novel analogue CMOS circuit is presented which performs the arithmetical squaring of a voltage, using the square-law characteristic of the MOS transistor in saturation. The core circuit is constructed from four identical building blocks, which are connected so as to eliminate all unwanted offset terms. Simulation results from HSPICE are presented where the circuit is used for doubling the frequency of a sinusoidal input. Introduction: There is a wealth of analogue circuits in the literature suitable for VLSI implementation which synthesise analogue functions by exploiting the square-law transconductance characteristic of the MOS transistor in the saturation region,

A CMOS class AB current mirror whose supply requirements are restricted to one threshold voltage plus three saturation voltages is presented. The circuit uses two poly resistors and two auxiliary differential amplifiers to achieve low-voltage operation, as well as control of quiescent currents and input bias voltage. A design example is implemented in a 0.5-µ µ µ µm standard technology and uses a 1-V supply. It exhibits input and output resistances of 5 kΩ Ω Ω Ω and 3.6 MΩ Ω Ω Ω, respectively and a DC current gain of 0.03 dB over a bandwidth of 140 MHz. .

A brief review of recent progress in photonic integrated circuits (PICs) is presented. By examining Moore's Law and the roadmap of conventional electronic ICs, valuable lessons in host material selection for PICs are discussed. Finding a primary host material for integration is necessary and vital to the success of the PIC industry. Initial success has been achieved in both InP-based and silicon-based commercial PICs; however, we believe that cost and performance may select silicon as the primary host material, with the urgency to deploy optical interconnects on Si electronic ICs as one of the main reasons. A recently introduced hybrid silicon evanescent platform and devices and silicon/germanium APDs are reviewed as examples to understand the viability of silicon PICs and lead to an understanding of a possible roadmap to next generation large-scale PICs.

A practical approach to determining the distributed capacitance and inductance of individual metamaterial resonators is demonstrated. By loading a set of lumped capacitors onto the resonator, the resonance frequency can be measured as a function of the load capacitance. The capacitance and inductance values of the resonator are then determined by relating the equivalent circuit model to the measurements. Although the measurement is limited to the microwave region owing to the availability of suitable lumped capacitors, the concept is useful in simulations over a wider frequency range. The obtainable parameters are useful for further metamaterial analyses or syntheses.