A novel and compact wideband multiple input multiple output (MIMO) antenna for mobile terminals is presented. The proposed antenna operates over a wide frequency range of 1.79–3.77 GHz suitable for long-term evolution (LTE), worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) handheld devices. The MIMO antenna structure consists of two identical radiators with a small size of 10 × 17.7 mm² and a parasitic element with a T-shape. The radiators, which comprise four branches with a meandered strip feed, are symmetrically located with respect to the T-shaped parasitic element. The parasitic element is a novel design appended at the ground plane. By using this parasitic element, a better isolation performance has been achieved between the two radiators. The overall performance of the antenna in terms of s-parameters, radiation pattern, gain and envelope correlation coefficient is investigated and verified through measurements. The results obtained show that the proposed antenna has attractive physical properties due to being small, compact and embeddable in mobile handsets, and has good characteristics of wideband, isolation, gain and radiation pattern.

A dual-feed rectangular dielectric resonator antenna with a wideband switched line coupler is proposed for generating broadband circular polarisation. The new wideband switched line coupler provides good impedance matching, equal power splitting and consistent 90° phase shifting over a wide bandwidth. The proposed antenna exhibits a 3 dB axial ratio bandwidth of 47.69% and an impedance matching bandwidth of 48.46% for a voltage standing wave ratio ≤2.

A dual-band slot-coupled patch antenna for the external access point of the wireless local area network (WLAN) band is implemented. The antennas consist of two radiators on three layers. The first radiator is a slotted bow-tie antenna operating at the 2.4–2.483 GHz band. The second radiator is a patch antenna with parasitic elements operating at 4.095–5.845 GHz. To enhance the bandwidth, a coupled feeding was used in the first radiator and a parasitic patch was used in the second radiator. To improve the directivity and isolation in both the radiators a parasitic patch and chock were used. The peak gain was more than 6 dBi in the first antenna and more than 8 dBi in the second antenna.

A rectangle-shaped aperture antenna for ultra-wideband (UWB) applications which can prevent the interference problems is presented. By attaching a hollow-cross-loop resonator (HCLR), triple-notched frequency bands centred at 3.5, 5.7 and 8.2 GHz are obtained. The HCLR is loaded in the aperture over the microstrip feedline. The proposed antenna has been successfully simulated and measured. Based on the results, it is shown that the proposed antenna yields an impedance bandwidth of 2.55–12 GHz with a voltage standing wave ratio (VSWR) < 2, except for the triple-notched bands of 3.15–3.85 GHz (WiMAX band), 5.4–6.1 GHz (WLAN band) and 7.8–9.3 GHz (X-band satellite communication).

A novel design of a biped robot inspired by domestic cats for fast running is introduced. The skeletomuscular system of a cat is analysed and applied to determine the link parameters and the linkage structure of the proposed mechanism. The linkage design of the leg mechanism is explained and a kinematic analysis based on vector loop equations is performed. The effectiveness of the proposed mechanism is verified experimentally. The biped robot runs at an average speed of 2 m/s at a step frequency of 4 Hz. This leg mechanism can facilitate the development of fast running robot systems.

Respiration rate is an important measure for assessing a patient's health and is typically measured using obtrusive devices. A non-obtrusive method of estimating respiration rate by taking advantage of data packets being sent from sensor nodes in a wireless body area network is proposed and investigated. In contradistinction to other methods, the proposed method does not require dedicated hardware and does not impose overheads on transmission power and throughput. Instead, it makes use of data packets already being sent to support some other physiological monitoring applications such as cardiac, temperature or motion monitoring. The method is demonstrated on a single subject and results are presented from a study including 40 measurements taken from eight subjects. The mean estimation error in the study was 0.58 breaths per minute. The proposed method can be used to augment wireless body monitoring applications with important respiration rate measurements without imposing overheads on the compact sensor nodes.

Although haptic feedback is critical for many surgical tasks, surgeons cannot currently obtain haptic feedback from teleoperated surgical robots because it is difficult to attach force sensitive sensors to the surgical robot in the surgery environment. Therefore, force sensitive forceps with an optical fibre Bragg grating sensor attached on the grasper are proposed. The proposed prototype forceps confirmed that the sensitive grasping force in the teleoperated grasper is comparable to the providing force and measuring force.

The power cepstrum-based parameters for steady-state visually evoked potential (SSVEP) is proposed. To precisely represent the characteristics of frequency responses of a visually stimulated electroencephalography (EEG) signal, power cepstrum analysis is adopted to estimate the parameters in low-dimensional space. To represent the frequency responses of SSVEP, the log-magnitude spectrum of an EEG signal is estimated by fast Fourier transform. Subsequently, the discrete cosine transform is applied to linearly transform the log-magnitude spectrum into the cepstrum domain, and then generate a set of coefficients. Finally, a Bayesian decision model with a Gaussian mixture model is adopted to classify the responses of SSVEP. The experimental results demonstrated that the proposed approach was able to improve performance compared with previous approaches and was suitable for use in brain computer interface applications.

The design of a single-stage operational transconductance amplifier is presented, which uses self-cascode transistors and current shunt stages to improve its DC gain. The proposed amplifier is implemented in a standard 45 nm silicon on insulator CMOS process. Simulation results show that the amplifier has a DC gain above 50 dB despite physical and environmental variations with a minimum gain bandwidth product of 540 MHZ and more than 55° phase margin. In addition, the simulated transient behaviour is shown to be robust, with a slew rate of 500 V/μs and a settling time of 7 ns with 1% accuracy for a C _L of 0.3 pF.

As NAND flash cell sizes have been scaled down, endurance characteristics have suffered severe limitations in the NAND flash memory. Two NAND flash cell structures, the wing spacer structure and the no wing spacer structure, have been constructed to compare their endurance characteristics. The wing spacer structure has more trap sites at the active edge area due to program/erase (P/E) cycle stress because of the short distance from the active edge to the control poly. Thus, the endurance characteristics are degraded by traps generated at the active edge area. In addition, it has been confirmed that the threshold voltage (V _T) shift of the wing spacer structure was about 15.2% higher in erased cells and 10.9 % higher in programmed cells than those of the no wing spacer structure after the stress of 10⁴ P/E cycles.

A power-efficient, low-noise, broadband amplifier is demonstrated in a 130 nm SiGe BiCMOS process. The circuit exhibits a 20 dB gain, 86 GHz bandwidth and consumes only 89 mW DC power, achieving a gain-bandwidth against DC power efficiency of 9.66 GHz/mW – a significant improvement over the prior art. Ultra-high data rates (>80 Gbit/s) are supported owing to a low group delay variation of ±5.9 ps up to 100 GHz. Intended as a low-noise transimpedance front-end for optical receivers, the circuit exhibits a low average input-referred-noise of 20.4 pA/✓Hz, which is comparable to or better than the state-of-the-art at much lower data rates.

A simple yet effective method to reduce the dimensions of the input variables and is adaptive to various users for intelligent controllers is proposed. The method has been developed specifically to address the challenge due to fuzziness in the system inputs, especially when studying the relationship of a large mapping between input variables and system response outputs. The proposed method exploits the principal components analysis to reduce the number of inputs and uses a fuzzy c-means technique to cluster them. The objective is to extract significant principal components for adaptive neural fuzzy inference systems (ANFIS) learning. The method has been applied to a robotic walker system for elderly movement assistance. Experimental results demonstrate the feasibility of the proposed method.

The concept of using additive manufacturing as a method to construct heterogeneous substrates from a single building material via stereolithography is introduced. The dynamic variation of air cavities within the bulk material is used to control the effective permittivity of the host medium. The digitally driven layer process enables full three-dimensional variation of the local permittivity. The high resolution of stereolithography enables sub-millimetre control of air inclusion features. Measurements of the effective permittivity with different air fractions have been compared to analytical results.

An enhanced constrained one-bit transform (C1BT)-based fast motion estimation (ME) method is proposed. Binary transform-based ME identifies the proper motion vector by transforming the 8-bit pixels in the original image into a low bit depth of the bit plane, substantially reducing the computational complexity and facilitating hardware implementation by using the number of non-matching points (NNMPs) instead of the sum of absolute difference (SAD). However, a motion block size is N × N, therefore the dynamic range of NNMP (0 ≤ NNMP ≤ N × N) is decreased to 1/256 compared to that of the SAD with 8-bit images (0 ≤ SAD ≤ 256 × N × N). The higher the NNMP between the current bit plane and the previous bit plane, the more probable that it will be the block most similar to each other. Therefore, the matching error criterion of NNMP is extended to improve ME performance. Experimental results show that the proposed algorithm improves the performance of ME accuracy by 0.27, 0.38 and 0.67 dB compared to the C1BT-based ME, two-bit transform (2BT)-based ME and 1BT-based ME, respectively.

Coding unit (CU) splitting and pruning for complexity reduction in high-efficiency video coding (HEVC) intra coding is dealt with. Adaptive determination of the threshold values for splitting and pruning in each CU is proposed based on the depth level information of neighbour CUs, whose values are determined from a fixed parameter in the previous method. Simple preconditions for splitting and pruning are also proposed to improve coding efficiency. Simulation results show that the proposed method gives significant improvement of computational complexity with much smaller reduction of coding efficiency compared with the previous method.

To obtain a high coding gain, high-efficiency video coding employs the recursive quad-tree structured coding unit (CU) for the smallest coding layer. The computational complexity, however, increases dramatically because the CU and its associated prediction units (PUs) are tested thoroughly by the rate-distortion (RD) optimisation method. To reduce the computational complexity, a fast CU decision algorithm is presented based on skipping of inter and intra PUs by checking the coded block flag (CBF) and RD cost. Experimental results show that the proposed algorithm saves ∼35.39% of encoding time.

Multi-modal medical image registration remains a challenging and active area of research owing to the difficulty of dealing with intensity distortions. Local patch-based entropy images were recently proposed to address this problem. However, this method suffers from the complexity of calculation of the entropy. Proposed is a new dense descriptor for an image, named the edge neighbourhood descriptor, which assigns different values to different image regions, namely the image background, image edges, edge neighbourhoods and the remaining area. The edge neighbourhood descriptor is faster than the entropy image. Experimental results show that this new descriptor can improve registration accuracy compared with the results of the entropy image and the mutual information method.

The increasing demand for wireless broadband services poses the need for efficient utilisation of the backhaul network resources. To this end, schemes that use artificial neural networks in order to predict the forthcoming network traffic demand and proactively request the commitment of the necessary resources have been proposed. However, an up-to-date prediction model, required by these schemes, necessitates a regularly held training process, which incurs a high computational cost. This reported work investigates the trade-off between prediction accuracy and computational efficiency by employing evolutionary game theory and a novel scheme is proposed that can achieve both the aspects.

Some new bounds are presented for multiple burst-correcting codes that extend the previously known bounds, such as the Reiger and the Gallager bounds. It is shown that both the new bounds coincide for block codes. For some values, the new bounds improve the extended volume bound.

A Ka-band dual-gate frequency doubler using 0.5 μm GaAs enhancement-mode pHEMT process is presented. The cascode circuit is equalised to the dual-gate frequency doubler and the relationship between bias and output matching is discussed to obtain the maximum output power and conversion efficiency. Since a pinch-off gate-to-source bias is driven at the input gate node, the frequency doubler consumes little DC power when injecting a low-power fundamental signal. Based on the analysis, the designed dual-gate doubler has a 3 dB bandwidth of 5.6 GHz, from 36 to 41.6 GHz. The fundamental suppressions are better than 15 dB. The measured maximum conversion gain is −0.9 dB at an injected power of 7 dBm. A high saturation output power is 7 dBm with a conversion efficiency of 14.3%. The measured results confirm the validity of the proposed analysis method.

A compact dual-band power divider based on a dual composite right/left-handed transmission line is presented. The measured results show that for the presented power divider operating at 1.9 GHz with a 94.2% bandwidth (1.00–2.78 GHz) and at 6.6 GHz with a 12.9% bandwidth (6.25–7.10 GHz), in which the return loss is <−10 dB, the variation of measured |S21| and |S31| is within 3 ± 0.5 dB. Compared with the conventional transmission line power divider operating at 1.9 GHz, the presented one not only realises dual bands but also realises a 24% size reduction.

A compact microstrip lowpass filter (LPF) with sharp roll-off is presented. The proposed filter consists of radial resonator, triangular patch and open stub. The proposed filter has good specifications such as low insertion loss <0.1 dB, high return loss of −20 dB, wide stopband from 4.37 to 19 GHz with −20 dB attenuation level and compact size. The LPF filter has a cut-off frequency of 3 dB at 4.24 GHz and a high roll-off rate of 130.7 and finally a high figure-of-merit of 23526.

The use of pulse-coded signals over each colour component on a colour shift keying (CSK) modulation is explored. This codification improves the time-synchronisation recovery capability on the IEEE 802.15.7 PHY III standard and reduces the overall system complexity. Different symbol codification rates are studied so as to improve the symbol error rate while minimising the effect over the throughput of the whole system.

A high-performance micromechanical disk resonator is developed for use in mass detection biosensors. The resonator is designed to facilitate easy and cost-effective fabrication by anchoring the disk on the side stems and increasing the capacitive gap size up to 4.75 µm. The designed disk resonator operates in an elliptic contour-mode at a resonance frequency of 5.971 MHz with a quality factor of 4272 in ambient air condition and 17 221 in a 600 Torr vacuum environment.

Dielectric charging is a major reliability issue preventing commercialisation of RF MEMS capacitive switches. To date two major modes have been considered as responsible for the charging of the dielectric films in RF MEMS. The one takes place during the pull-down state and therefore it is called contacted or injection charging, whereas the second occurs when the bridge is still in the up state and is referred to as contactless or induced charging. Experimental results supporting contactless charge injection as an additional charging mechanism in RF MEMS capacitive switches are presented.

The generation of a picosecond pulse train is demonstrated taking advantage of the cross-gain occurring in a dispersion-oscillating fibre. The resulting frequency-converted signal is detuned by more than 20 nm from the pump and can be temporally compressed by a factor of 2 compared with the input sinusoidal pump wave.

The design and implementation of a simple integrated magnetic (IM) transformer for an LLC resonant converter are presented. The IM transformer with a resonant inductor is implemented using a flexible magnetic sheet. Experimental results are provided to show the validity of the proposed IM transformer.

A low quiescent current low dropout linear regulator (LDR) with a combination structure of a bandgap and an error amplifier is presented. The circuitry is achieved with a combined structure which is able to obtain a lower quiescent current, because the current for the specific bandgap reference can be omitted. The transient response enhancement circuit can activate an additional path to control the gate voltage of the pass device which assists in monitoring the variation in the output voltage in the steady state. According to restrictions of the process and the product requirements, this proposed LDR is implemented with high-voltage tolerance double-diffused MOS (DMOS) in a 0.6 μm BCD process. The LDR has a quiescent current of 3 μA and is able to deliver a 50 mA load current.

The relationships between phase distortion, bias point and load modulation in power amplifiers are experimentally evaluated for two different GaN HEMT technologies. Measurements on devices with fixed and modulated load, to emulate the dynamic working conditions of the main stage of a Doherty amplifier, have been carried out through an advanced source/load-pull setup. Almost flat phase distortion against output power can be obtained by the proper bias point when the load remains constant, whereas it is shown that this possibility is not compatible with load modulation, inherently present in Doherty power amplifiers.

A low-loss switchable superconducting filter is presented. High Q resonators loaded with switchable superconducting interdigital capacitors are introduced. A two-pole 2-bit switchable high-temperature superconducting (HTS) filter at 516 MHz with a bandwidth of 29 MHz is designed and fabricated. The measured centre frequency tuning range is 33 MHz (6.4%). In all states, the HTS filter with pin diode switches exhibits an insertion loss <0.81 dB and a good return loss better than 16.8 dB.

Novel lower and upper bounds on the symbol error rate of the minimum distance detector are derived for signal constellations impaired by additive isotropic (i.e. spherically symmetric) generalised Gaussian noise (GGN). The proposed bounds depend only on the constellation dimensionality, the shape parameter of the GGN distribution and the maximum and minimum distances between the constellation points. They are expressed in terms of the well-known Gamma and upper incomplete Gamma functions. An asymptotic analysis of the proposed bounds establishes the sphere hardening effect, which plays a prominent role in the design of high-performance modulation systems, in the case of additive isotropic GGN channels.