A novel mobile terminal antenna covering the low LTE and GSM850/900 communication standards (i.e 700–960MHz) is proposed. The two-port antenna is composed of two coupling elements manufactured on a plastic piece using a laser direct structuring technique. To obtain a high port-to-port isolation between the two feeds, a neutralisation technique is applied. Simulated reflection coefficients and total efficiencies are compared to the measured data showing good agreement and competitive performance.

A high signal-to-noise ratio (SNR) in silicon nanowire (SiNW) field effect transistors (FETs) is crucial for detecting low concentrations of biological material as the signal changes are often small and difficult to be differentiated from the baseline signal. This reported work studies the low-frequency noise (1/f) as in Hooge's constant, α _H, and the device detection limit of the SiNW FETs to evaluate the influence of the etching process used to define the nanowires (NWs). Two etching methods are compared: plane-dependent etching using potassium borate in water and reactive ion etching in Cl-based chemistry. All investigated devices have similar dopant type, doping concentration and dimensions, and were fabricated with the same process flow with the exception of the NW definition. The extracted average Hooge's constant for wet etching is found to be at least an order of magnitude lower (α _H, avg = 7.96 × 10⁻⁴) compared with dry plasma-etched devices (α _H, avg = 4.1 × 10⁻²), indicating a lower surface roughness and/or a lower amount of surface defects. This study shows that the newly developed method improves the electrical properties of the device, making it an interesting alternative to standard approaches used for fabrication of SiNW FETs as (bio)sensors.

With the advent of implantable hearing aids, the implementation and acoustic sensing strategy of the implantable microphone becomes an important issue. Previously, implantable microphones were inserted under the skin, which causes loud noise signals from touching or moving the skin. In this reported work, mounting a microphone in a drilled hole to the middle ear cavity is proposed. This method does not cause any skin movement problems or aesthetic problems. Furthermore, surgical operation is easy because the microphone can be mounted onto the drilled bone and does not need to be clipped or attached to the ossicular chain. From guinea pig experiments (n = 5), the loss of transmission from the proposed microphone observed was only 1.17 ± 0.36 and 5.04 ± 0.84 dB (mean ± std.) for the 0.2–1 and 3–4 kHz bands. The lowest minimum detectable sound pressure was measured as 27.7 dB SPL (SNR: 6 dB) at 3150 Hz without pinna or canal effects.

A compact expression describing the transient behaviour of the Van der Pol oscillator is presented. An original simplification on the amplitude variation leads to a new expression of the oscillation phase transient behaviour. This new expression is particularly suitable for describing oscillator relaxation, i.e. when the oscillator switches from a forced to a free oscillation state. It is shown that by choosing the injection stop instant correctly, the free running frequency can be achieved instantaneously.

Proposed is a novel digital redesign under an integral state-matching performance index, which considers the inter-sampling state-matching that the previous works ignore. The example result demonstrates that the developed technique improves the state-matching performance.

Space-time adaptive processing algorithms have been proven to be a very effective way to mitigate the effects of multipath and interference. Due to the fast-changing clutter scenario, the stationary property of the data is destroyed and fails if the interference scenario ever becomes heterogeneous. Direct data domain (D³) methods can accommodate non-stationary data and can effectively suppress the clutter. However, the computation of D³ is very intensive. It is desirable to implement the D³ algorithm on a FPGA architecture for real-time applications. FPGAs can accommodate parallel and pipelined architecture. Here, the first FPGA design for the D³ algorithm and a new software package are presented. The software tool is capable of auto-generating a fully optimised VHDL representation of D³ and provides various performance parameters. The tool can be used by the designer to develop an overall system on chip (SoC) by using various constraints and options to meet certain performance criteria. Experimental results demonstrate that the authors' hardware version of the D³ algorithm can significantly outperform an equivalent software version.

The proposed scheduling scheme minimises the mean power consumption of real-time tasks with probabilistic computation amounts on multicore processors. To reduce leakage power consumption of idle cores, the scheme activates a part of available cores while turning off the power of unused cores, and determines the instant speed of activated cores so that the expected power consumption of real-time tasks would be minimised.

Plane wave scattering from a cubic resonator is calculated by solving the combined field integral equation with the Rao-Wilton-Glisson basis functions and the moment method. High dielectric cube calculations show that magnetic and electric dipoles are found at the first and the second modes, respectively, whereas the third resonant mode has simultaneously strong electric and magnetic fields at the same resonant frequency. Furthermore, an analysis of a magnetodielectric cube is discussed.

Presented is the effect of sharp spark gap on time lag, which is a very important factor in electrostatic discharge modelling. A long time lag induces a large discharge current and a fast rise time. The large discharge current often causes soft errors in many products. Through measurement and simulation, the relation between sharp edge and time lag is quantified. The result can be used in numerical simulation of breakdown voltage. With the numerical simulation, knowing only the geometry of the spark gap can obtain the discharge current.

A novel voltage-programmed pixel circuit is proposed to achieve an active-matrix organic light-emitting display (AM-OLED) based on a low temperature polycrystalline silicon thin-film transistor (TFT) with an enhanced electrical stability and uniformity. The proposed pixel circuit consists of one driving TFT, one setup TFT, four switching TFTs, one capacitor, and four control signal lines. Through an extensive simulation work based on the HSPICE tool, it has been verified that the proposed pixel circuit can compensate for both mobility variations and threshold voltage shifts of the driving TFT.

Bidirectional motion compensation is an efficient method for frame rate upconversion application. To enhance bidirectional motion vector field (MVF) accuracy, most recent approaches derive it from unidirectional motion vectors (MVs), which may introduce blocking artifacts around object boundaries due to the block-wise motion assignment. Presented is a joint trilateral motion vector filter to improve the MV accuracy of boundary pixels by increasing the resolution of the block-wise unidirectional MVF to a pixel basis. The MV of each pixel is computed as a weighted average of its neighbouring block MVs. Experimental results show that the proposed method can improve the MV accuracy of boundary pixels effectively. Frames interpolated by the proposed method achieve better performance compared with conventional methods.

Proposed use lightweight generic random ferns (LGRF), a fast keypoint classifier designed for multi-target augmented reality (AR) on mobile devices. LGRF uses binary features of image patches for both object recognition and keypoint matching of multiple objects, and stores probabilities in a single bit representation to reduce memory requirements. As a result, LGRF can perform simultaneous object recognition and keypoint matching in real time with low memory consumption, making it suitable for multi-target AR on mobile devices.

Presented is a novel technique to fuse multi-sensor images using non-subsampled shearlet transform (NSST) domain I²CM. First, multi-scale and multi-directional decompositions of source images can be performed by NSST. The classic ICM is improved to be I²CM which is then exploited to capture and extract the characteristics of each of the sub-band images. Finally, the fused image is reconstructed from the fused sub-images by adopting the inverse NSST. Experimental results demonstrate that the proposed image fusion scheme is very competitive compared with other conventional ones in both visual effect and objective evaluation criteria.

Proposed is a human action recognition method by partwise bag-of-words (BoW)-based multi-task learning. The authors present partwise BoW representation and furthermore formulate the action recognition task as a joint multi-task learning problem by transfer learning penalised by a graph structure and sparsity to discover latent correlation and boost performances. A large-scale experiment shows that this method can significantly improve performance over the standard BoW + SVM method. Moreover, the proposed method can achieve competing performances against the state-of-the-art methods for human action recognition in an effective and easy to follow way.

First a novel sketch filter based on the maximum filter is proposed. The proposed sketch filter implicitly calculates the complexity of local area, and results in an image which expresses edges and textures as an artist draws a sketch with a pencil. It is then proposed to apply the sketch filter for edge feature extraction, colour pencil drawing, and the animation filtered image. The proposed algorithms work automatically without any interaction and demonstrate impressive results for rendering applications, while requiring a much smaller amount of computations compared to existing schemes.

The non-local means (NLM) method explores self-similarities in images for noise removal. The traditional NLM (TNLM) method computes pixel similarity using the globally fixed decay parameter. However, a fixed decay parameter for the whole image makes it difficult to ensure that the TNLM method can restore both edge pixels and non-edge pixels effectively. To address this problem, the SUSAN controlled NLM (SNLM) method is proposed to adaptively tune the decay parameter for each image pixel based on the SUSAN edge response. Extensive simulations demonstrate that the SNLM method outperforms several state-of-the-art NLM methods in terms of noise reduction and detail preservation.

A partial-forward scheme for the half-duplex relay system is proposed, which transmits only a part of codewords by considering code and channel characteristics at the relay. Specifically, two partial cooperation schemes, decode-and-partial-forward and amplify-and-partial-forward schemes are considered and to overcome the shortcomings of these schemes an adaptive partial-forward scheme is proposed which can be flexibly applied according to the given environment. Also, the criteria on how to select a part of the codeword bits at the relay are derived. Furthermore, the optimisation of the time-division parameters to obtain the performance improvement is investigated.

For efficient hardware implementation of QC-LDPC encoders, four types of rotate-left-accumulator (RLA) circuits are proposed. Although the performance of a type I RLA circuit is exactly identical to the most widely used shift-register-adder-accumulator (SRAA) circuit, its reasonable structure can derive the other three counterparts. Both type II and III RLA circuits are highly area efficient, and have the same speed as the SRAA circuit. Compared with these serial-in circuits, the parallel-in type IV RLA circuit is faster at the cost of more memory, and suitable for applications where generator matrices have fewer block rows or special parity-check matrices are used to encode.

A trellis-coded coordinate-interleaved orthogonal design (TC-CIOD) for four transmit antennas with a rotated QAM base signal set is introduced. To design a high rate pre-encoder the base signal set is expanded by conjugating the rotated QAM signals without changing the transmit signal set at each transmit antenna. The proposed TC-CIOD provides coding gain without increasing peak-to-average-power ratio.

If the wave output by a voltage controlled oscillator (VCO) has the property of having no phase jump also when its frequency is swiftly changed, the measures of the phase before and after a fast frequency change can be used for calculating the time at which such event has occurred. Based on this property, a precise time measurement instrument has been designed and built. A non-optimised version has better than 100ps resolution full width at half maximum, is VCO drift compensated and is able to time events against a stable clock running at 312.5MHz. The VCO frequency of the prototype jumps from 47 to 59MHz. The analogue hardware is fairly limited. Applications may range from particle timing to time resolved fluorescence spectroscopy to range finding through time-of-flight methods.

Multichannel coil arrays are increasingly being used to improve signal-to-noise ratio in magnetic resonance imaging (MRI). The decoupling between coils is an important parameter in array design. Indeed coupling between elements affects the resonance frequency of each single coil and decreases its sensitivity. Many solutions have been developed to achieve decoupling between elements of the multichannel coil array. Presented is a capacitive solution to restore channel decoupling of a specific four-channel receiver coil array using common conductors. The principle of an effective decoupling was first demonstrated by circuit simulations of |S|-parameters. A receive-only four-channel coil array was design for rat head MRI. Experimental |S|-parameter measurements validated the proposed capacitive approach by restoring decoupling between elements and particularly between external loops.

Presented is a monolithic microwave integrated circuit (MMIC) resonant tunnelling diode (RTD) oscillator that employs two In_0.53Ga_0.47As/AlAs RTDs (5 × 5 µm²) in parallel. The oscillator works at 28.7 GHz with −0.7 dBm output power. The phase noise was −95 dBc/Hz at 100 kHz and −114 dBc/Hz at 1 MHz offset. This reported work demonstrates the potential of RTD oscillators in achieving high output power at high frequencies by utilising suitable power maximising and combining techniques.

A compact wideband filter with a wide upper stopband using stub-loaded multiple-mode resonators is designed. The multimode behaviour and characteristics of the proposed filter structure are studied by conventional natural modes analysis. A prototype is designed and fabricated at 1 GHz (f ₀) with 3 dB fractional bandwidths 102% and 20 dB stopband attenuation up to 10.75f ₀. Good agreement between simulations and experiments is observed.

Double-negative metamaterials using cross-polarised split-ring resonators in a microstrip line have been implemented. The split-ring resonators comprised quad ring structures and were connected with the microstrip line in series. Four different structures, with the shorted rings in varying locations, were fabricated to demonstrate reconfigurable bandpass characteristics. The effective permittivities and permeabilities were extracted using the Ziolkowski method. Excellent agreement between the developed circuit model and the measurement was observed up to 10 GHz.

A wideband isolation topology of a power line is proposed, using open stub structures for high-speed digital interconnects. To reduce the coupled noise to the power line in the absence of a common-mode choke (CMC), which could degenerate signal integrity due to its loss and unbalanced properties, ferrite bead and open stub structures are utilised as they are suitable to the small size of commercial systems. In terms of the enhanced isolation characteristics, the induced power noise is reduced from 83 to 12 mV (86% reduction ratio) under a mobile high-definition link data transfer without data losses. Therefore, the proposed open stub structures are a very effective tool for both power integrity and signal integrity, and most importantly the cost is minimal when the CMC is removed from the high-speed digital interconnect.

A double-side-swap phase inverter is proposed in the rat-race hybrid. This phase inverter with a 90° line replaces the conventional 270° line in the hybrid, which results in a size reduction and widening of the bandwidth. In microwave components, a large ground plane has the advantages of acting as an effective reflector in antenna systems and providing excellent heat sinking in high power applications. Experiment shows that this proposed hybrid has good performance from 1.2 to 2.8 GHz (f_o = 2 GHz). The bandwidth is increased from 10 to 80 %, respectively, and a 43 % size reduction is obtained compared with the conventional rat-race hybrid.

The benefits of a redundant channels methodology for the component calibration are explored. Proposed is a normal approximation of the yield in order to estimate the number of redundant components needed to provide a minimal area occupied by the components.

Cycle slip adversely affects transmission performance in digital coherent systems. Proposed is an algorithm using statistical analysis for suppressing cycle slip in a digital coherent system. The cycle slip suppression effect, transmission performance, and nonlinear tolerance of the proposed algorithm were numerically investigated. The proposed algorithm enables cycle-slip-free wavelength division multiplex transmission under the presence of nonlinear optical effect and improves transmission performance.

A piezoresistive pressure sensor has been fabricated with a newly proposed fabrication process, which is quite suitable for fabricating MEMS devices. The fabricated pressure sensors are wire-bonded and have been tested under the pressure range from 100–1012hPa. The results show that the output voltage increases with the applied pressure. For the structures with membrane length of 800 and 900 µm, the output voltage is linear to the pressure applied and the sensitivity of the sensor is about 0.75 and 0.877mV/hPa. The test results also show that, in order to get a linear output, the membrane length should be less than 1000 µm.

A resistive switching behaviour of printed, flexible Cu/CuO/(AgO)/Ag memristor devices is demonstrated for the first time. It is suggested that the high resistance state and low resistance state of bipolar resistive switching behaviour are governed by the migration of oxygen between the copper oxide and silver oxide layers. The devices have characteristics of inexpensive low-temperature fabrication, low-power operation and no required electroforming process. Ink-jet printing was used to fabricate the devices on polymer substrates. Since these devices are fabricated on flexible polyimide, they have compatibility with flexible electronic technologies.

The electrical properties of pn junctions, with various semiconductor materials with different doping concentrations fabricated by using surface-activated-bonding (SAB), were investigated by measuring their current-voltage (I-V) characteristics. The I-V characteristics of p ⁺-GaAs/n ⁺⁺-Si, p ⁺-GaAs/n ⁺-Si, p ⁺-Si/n ⁺-Si, p ⁺⁺-Si/n ⁺-InGaP, and p ⁺-Si/n ⁺-InGaP junctions showed ohmic-like properties. The interface resistance and the resultant electrical loss decreased with increasing impurity concentration at the interface. These results demonstrate the significance of SAB for fabricating tandem solar cells.

As device dimensions become increasingly challenging to scale down, the high-mobility channel solution is gaining more interest. However, will good carrier transport alone guarantee the continuation of higher drive current at shorter dimensions and lower power supply? The technology scaling of FO4 delay and energy delay product of III–V/Ge logic for beyond-22-nm technologies was investigated. The circuit performance estimation was projected down to 11 nm technology by using a physics-based compact model developed for III–V field effect transistors. The analysis shows that the realisation of good electrostatics and low series resistance is crucial for the scalability of high mobility channel devices.

Laser frequency combs based on optical parametric oscillators provide widely tunable sources of regularly spaced frequencies from the visible to the mid-infrared, with potential applications in precision metrology, spectroscopy and astronomy. Reported is the extension of the comb mode spacing into the GHz domain by using a Fabry-Pérot cavity, the length of which was electronically stabilised to a harmonic of the original pulse repetition frequency via a dither-locking technique. A 1500 nm femtosecond optical parametric oscillator frequency comb, the repetition frequency and carrier-envelope offset frequency of which were locked to 280 MHz and 10 MHz, respectively, was filtered by a high-finesse cavity to generate a pulse sequence at 1.4 GHz, corresponding to a factor of five increase in the mode spacing of the comb.

A full-duplex data link at 10 Gbit/s per channel (two upstream and two downstream) between two compact bidirectional optical sub-assemblies is presented. Each sub-assembly is based on the authors' optoelectronic ferrule and carries both laser diodes and photodiodes while maintaining a compact form factor of less than 20 mm³. The authors use plastic optical fibres with 50 µm graded-index cores and thin 125 µm claddings bundled in a four-channel ribbon but split the ribbon in order to reach both laser diodes and photodiodes within the optoelectronic ferrule, hence directly butt-coupling each channel with its own optical fibre. This method keeps both assembly form factor and complexity at a minimum and performance high. Eventually error-free signal transmission at 10 Gbit/s per channel over 5 m with 0.67 unit intervals eye opening is confirmed.

A new plasmonic-like waveguide structure is proposed for integrated terahertz refractive index sensing. The surface plasmon-like wave is an effective means for high sensitivity sensing in the terahertz range, but most of the reported configurations are based on free space excitation using a prism, that is not convenient for integration. In the proposed structure a dielectric waveguide is used to excite the sensor. Dispersion characteristics and the sensitivity of the structure are calculated using COMSOL full-wave simulations.

Presented is an electrically pumped passively modelocked edge-emitting semiconductor laser system in an external cavity setup with intracavity dispersion management. This concept, in combination with a pulse compressor, provides pulses as short as 158 fs. By expanding the setup with a tapered diode laser amplifier, peak powers up to 6.5 kW were achieved in the 850 nm wavelength range.

A temperature- and strain-independent torsion sensor based on analysis of polarisation-dependent loss (PDL) characteristics of high-birefringent (Hi-Bi) fibre Bragg gratings (FBGs), is proposed and demonstrated. Unlike the amplitude spectra, the PDL response has higher sensitivity to torsion. Experimetal results demonstrate that the difference between the two peaks in the PDL spectra has a linear relationship with the twist rate, but remains invariant with changes in temperature and strain. In addition, it was observed that the PDL responses to the clockwise twist are just opposite of the responses to the couterclockwise twist.

The ‘constant-flux’ concept has been described in a recent Letter as a way to utilise space more efficiently for inductor geometry with the core enclosed by winding. While the concept can conceptually be extended to the companion case of the inductor with winding enclosed by the core, structural synthesis is complicated by the absence of circular symmetry. Thus, this Letter delineates a procedure to shape the core and distribute winding turns to realise a magnetic field profile that is advantageous not only from the density standpoint, but also from the thermal standpoint via the reduction of hot spots, and from the reliability standpoint via the suppression of flux crowding. Design and fabrication results are delineated for a constant-flux inductor with the same specifications as a commercial counterpart, but the total height of the inductor is reduced by a factor of two.

A wideband electric interface based on pulse width modulation (PWM) for a piezoelectric energy harvester is investigated. The switching interfaces are used to increase the output power of energy harvesting devices for a wide frequency range. It is shown that the energy harvesting technique can effectively enable harvested power to be the maximum possible value for a dynamic electromechanical system for all excitation frequencies. The proposed wideband interface is composed of a full-bridge converter with PWM modulation. The piezoelectric voltage is adaptive to the vibration. In the final experiment, the PWM interface harvested more energy in the case of multi-frequency vibration.

Using a transformation of the order statistic for a series of Pareto distributed random variables, a linear regression approach is applied to estimating Pareto parameters for data sets. This method is shown to perform better than a standard maximum likelihood estimation procedure.

Forward imaging radar using an UWB signal has been developed by many researchers. The image quality in this radar is not satisfactory because of the limitation of aperture length. Proposed is an image enhancement method using a modified apodisation technique in forward imaging radar. An experiment is carried out to validate the proposed method. The azimuth resolution and peak-to-sidelobe ratio are improved by the proposed method by up to about 11.7% and 10 dB, respectively.

For multiple-input multiple-output cognitive radios, a single transmit and receive antenna selection scheme is proposed for when the channel state information from a cognitive transmitter to a cognitive receiver is unknown to the transmitter. In the proposed scheme, the transmit antenna at the cognitive transmitter that maximises the transmit power and the receive antenna at the cognitive receiver that maximises the signal-to-interference-and-noise ratio are selected. Also derived is the exact closed-form outage probability considering the peak interference power constraint, the peak transmit power constraint, and interference from the primary transmitter to the cognitive receiver.