A loop-type ground antenna with wide-band operation is proposed for USB dongle applications. The solution for improving the bandwidth is based on a resonant feeding circuit that includes both an inductor and a capacitor. By choosing an appropriate ratio of the inductance to the capacitance, the impedance bandwidth (VSWR < 2) is 21.8% at 2.2 GHz, sufficient bandwidth to cover both the WCDMA and WiMax frequency bands.

Two shorted inverted-L radiating elements are located on the orthogonal corner of the square substrate and connected to each output port of a Wilkinson power divider. A shorted inverted-T strip is placed on the other corner of the square for a perturbing resonator to generate circularly-polarised (CP) radiation in the UHF band. Proper adjusting of the horizontal and vertical lengths of the inverted-T strip will differentiate two orthogonal linearly modes with 90° phase difference for a good CP radiation. Simulated and measured results indicate that the proposed structure can achieve circular-degree polarisation operation. A measured impedance bandwidth (VSWR ≤ 2) of about 16.4% (810–960 MHz) and a 3 dB axial-ratio (AR) bandwidth of about 4.4% (890–930 MHz) at 915 MHz were obtained.

A dual-band circularly-polarised antenna implemented on a single substrate is proposed for Ku-band satellite communication. A microstrip-fed Spidron fractal patch is utilised to achieve dual-band resonance and circular polarisation. The proposed antenna, with dimensions of 50 × 50 × 1.52 mm³, has also been fabricated and tested. The measured −10 dB reflection bandwidths are 8.7% (11.44–12.48 GHz) and 6.6% (13.47–14.39 GHz), exhibiting a small resonant frequency ratio of 1.15. The 3 dB axial ratio bandwidths for the lower band and the upper band are 2.96 and 1.68%, respectively.

The performance of a Rotman lens, which forms fixed beams at 0°, ±15° and ±30°, is augmented using liquid crystal phase shifters to simultaneously steer each beam by up to ±7.5°. Measured results are used to demonstrate that the true time delay property of the antenna and voltage controlled phase shifters can be exploited to provide continuously scanned beams with full coverage over an angular range of ±37.5°, and with operation over the band 6–10 GHz.

An innovative antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed. This method is based on a capacitively loaded slot placed at the centre of the ground plane. The ground plane is 50 × 15 mm in length and width, respectively, which is the size typically used in USB dongles and headsets. The −10 dB impedance bandwidth is 12.9% at 2.4 GHz, fully covering the WiMax, Wi-Fi and Bluetooth frequency bands.

Compared to traditional classifiers, such as SVM, the extreme learning machine (ELM) achieves similar performance for classification and runs at a much faster learning speed. However, in many real applications, the different input points may not be exactly assigned to one of the classes, such as the imbalance problems and the weighted classification problems. The traditional ELM lacks the ability to solve those problems. Proposed is a fuzzy ELM, which introduces a fuzzy membership to the traditional ELM method. Then, the inputs with different fuzzy matrix can make different contributions to the learning of the output weights. For the weighted classification problems, FELM can provide a more logical result than that of ELM.

In vivo biosensing requires stable transistor operation in high-salt concentration bodily fluids while exhibiting impermeability to mobile alkali ions that would otherwise render the metal-oxide-semiconductor (MOS) threshold voltage to drift. Metal oxide semiconductor capacitor structures using Al₂O₃ as the gate dielectric were soaked in a sterile physiological buffer solution (PBS) up to 24 hours and for thicknesses from 100 to 10 nm. The triangular voltage sweep technique characterised alkali ion penetration, and measured no detectable alkali ions for the Al₂O₃ capacitors. By contrast, the dose of alkali ions in silicon dioxide MOS capacitors steadily increased with increasing soak times in the PBS solution.

Deep brain stimulation is an important therapy for Parkinson's disease patients. However, the current deep brain stimulator is open loop and cannot automatically adapt the stimulation according to the patient's condition. In this reported study a real-time wake/sleep identification device has been developed to wirelessly control the stimulation according to the patient's wake/sleep states. The wake/sleep identification was based on the wrist movement, and the identified result was transmitted wirelessly to the implantable pulse generator. This device showed a reliable radio frequency communication within 2 m and a low level of current consumption. This device also showed a good performance of real-time wake/sleep identification on Parkinson's disease patients. This study provides a promising application in the closed-loop deep brain stimulation, as well as other applications in medical services, such as night care, and fall alarm.

The design and implementation of an electrostatic discharge protection suitable for UHF RFID devices in CMOS technology is presented. The circuit implements three fundamental functions for the RF interface: power limiting, backscatter modulation and electrostatic discharge protection. Since all functions are achieved by the same MOS device the additional shunt capacitance at the RF inputs is limited. Therefore the maximum reading distance of the RFID device is improved without sacrificing the electrostatic protection level.

A single-stage driver is proposed. The LED driver is obtained by integrating an interleaved boost circuit and an LLC resonant converter. Since the interleaved circuit is adopted here, the input voltage is divided into two parts, each part sharing with one switch of the LLC resonant converter forms a boost circuit in discontinuous mode, and the power factor correction function and low bus voltage are realised. Since the LLC resonant converter is adopted, the converter works in soft switching state, which increases the efficiency of the system. A 100 W prototype is achieved to prove the analysis of the LED driver, and the efficiency of the LED driver is as high as 91% in full load.

A new method to improve the performance of low PSNR image denoising is presented. The proposed scheme estimates edge gradient from an image that is regularised with a relaxed geometric mean filter. The proposed method consists of two stages; the first stage consists of a second order nonlinear anisotropic diffusion equation with new neighboring structure and the second is a relaxed geometric mean filter, which processes the output of nonlinear anisotropic diffusion equation. The proposed algorithm enjoys the benefit of both nonlinear PDE and relaxed geometric mean filter. In addition, the algorithm will not introduce any artefacts, and preserves image details, sharp corners, curved structures and thin lines. Comparison of the results obtained by the proposed method, with those of other methods, shows that a noticeable improvement in the quality of the denoised images, that were evaluated subjectively and quantitatively, is produced.

Shadowing and illumination variations, caused by scene topography or non-uniform lighting, are present in virtually all image data. Given its prevalence and nuisance value when making quantitative image measurements, the development of accurate shading compensation techniques is essential. The linear mixture model of image formation is broadly employed when dealing with hyperspectral data but makes no explicit provision for shading and this can lead to inaccurate analysis results. In this reported work, the effect of shading on a hyperspectral image is demonstrated, and new methods for mitigating the effect using a forced-zero endmember and conical sub-simplex projection are presented. It is shown that together they provide the most accurate and theoretically sound shadow-corrected data.

For turbo codes with a coding rate close to one, the high puncturing rate induces long sequences of trellis without a redundancy bit. A simplification technique to compute the final state of a sequence of redundancy free trellis stages (RFTSs) is presented. It compresses a sequence of RFTSs of length N into a sequence of RFTSs of length m − 1 + (N mod (m − 1)), where m is the number of states of the trellis. The computation is reduced accordingly.

Proposed is an intuitive model for the effective code rate of HARQ-coded LTE transmissions. The model is derived from the circular structure of the rate matching buffer employed in LTE. Comparison with prior results, which were obtained by empirically extracting the code rates from the rate matcher, show the accuracy of the presented, entirely analytical, model.

Kalman filtering is one of the most widely used approaches to handling inertial sensors in pedestrian tracking systems. This technique uses a covariance error matrix to estimate position. This reported study leads to the hypothesis that there is no correlation between some elements of this matrix from one step to the next. Therefore, a selective reset of these elements at the end of each step improves position estimation. A set of these elements is proposed, and a statistical study is conducted using 32 data traces from the same path. Four parameters are analysed: the correction mean length, the position error, the altitude error and the travelled distance. As a result, all of these parameters obtain a loose statistical significance when the covariance error selective reset is applied.

A novel particle swarm optimisation (PSO) method with guaranteed convergence is proposed which is useful for various optimisation problems. This proposed algorithm searches for the optimum point by the PSO algorithm and at each iteration the optimum location found so far are corrected by the Kalman correction mechanism. This global convergence Kalman PSO (GKPSO) algorithm has been tested for many benchmark problems and the results compared with another popular PSO algorithm with a neighbourhood operator. The proposed algorithm converges faster than the other and also provides better quality of solution. Convergence to the global optimum for this proposed algorithm has been proved.

Presented is a square root algorithm in 𝔽 _q which generalises Atkins's square root algorithm [see reference 6] for q ≡ 5 (mod 8) and Müller's algorithm [see reference 7] for q ≡ 9 (mod 16). The presented algorithm precomputes a primitive 2 ^s -th root of unity ξ where s is the largest positive integer satisfying 2 ^s |q−1, and is applicable for the cases when s is small. The proposed algorithm requires one exponentiation for square root computation and is favourably compared with the algorithms of Atkin, Müuller and Kong et al.

Presented is a fully-differential inverter-based switched-capacitor second-order sigma-delta modulator for smart sensor applications. To reduce the supply voltage, the power consumption and the chip area, a simple inverter is used to replace the operational transconductance amplifier in the traditional integrator. The supply voltage can be lower than the summation of the absolute threshold voltages of the PMOS and NMOS transistors in the inverter. The described modulator has been designed and fabricated in AMI 0.5 µm CMOS process. Measurement shows that it can work under 1.5 V supply voltage and provide 55.39 dB signal-to-noise and distortion ratio (SNDR). Simulation also shows that the modulator can work under 0.7 V supply voltage and provide 59.38 dB SNDR in IBM 180 nm CMOS process.

A dual-modulus prescaler based on the heterodyne phase-locking technique is presented. Different to the conventional LC tank based phase-locked loop, by directly locking at two injection-locked ring oscillators simultaneously, a dual-modulus operation is achieved while a wide-range operating, significantly reduced settling time and low power consumption are achieved. Implemented in a standard 40nm CMOS process, the proposed divide-by-2 and 3 dual-modulus prescaler achieves an operating frequency of 6.3GHz with a measured power consumption of 0.6mW from a 1.1V supply.

A low power and low noise figure (NF) 60 GHz low-noise amplifier (LNA) with excellent phase linearity using standard 90 nm CMOS technology is reported. The LNA comprises a common-source (CS) stage followed by a cascode stage and a CS stage. The LNA consumes 14.1 mW, achieving S₁₁ better than − 10 dB for the frequencies 55.1–59.5 GHz, S₂₂ better than − 10 dB for the frequencies 55.1–59.4 GHz, and group delay variation smaller than ± 13.25 ps for the frequencies 50.4–63 GHz. Additionally, high and flat S₂₁ of 9.9 ± 1.5 dB is achieved for the frequencies 50.4–62.9 GHz, which means the corresponding 3 dB bandwidth is 12.5 GHz. Furthermore, the LNA achieves a minimum NF of 3.88 dB at 55.5 GHz and an NF of 4.73 ± 0.85 dB for the frequencies 50–63.5 GHz, one of the best NF results ever reported for a 60 GHz CMOS LNA.

An on-chip Ruthroff-type balun fabricated in tsmc^TM 0.18 µm CMOS technology has been realised and used in a single balanced mixer. By using the phase compensation line and appropriately choosing the characteristic impedance of transmission lines, the balun was realised with a minimum insertion loss of 0.71 dB and the 1 dB bandwidth over a frequency range from 3.2 to 8.4 GHz. The compact size of 0.088 mm² is achieved owing to the short length of the transmission line winding, approximately 1/18 λ _g , and the adoption of broadside-coupled and spiral-shape structures. A simple single balanced mixer with the Ruthroff-type balun was then designed to demonstrate the capability of the broadband and low-loss balun. A minimum conversion loss of 12.48 dB with a 3 dB bandwidth from 2.5 to 7 GHz was measured at the LO drive of only 6 dBm. The chip area, including pads, is 0.49 mm².

Wireless links using carrier waves in the millimetre-wave spectrum above 70 GHz provide a cost-effective solution to increase the data rate. Reported is the development of a photonically enabled link, based on two compact modules, both operated uncooled, transmitting a 1 Gbit/s data signal over several metres. The first module includes an optimised high-speed photodiode, delivering an output RF power exceeding 0 dBm (1 mW). Also reported is the development of a direct envelope receiver based on a quasi-optical Schottky barrier diode (SBD) module. Over the carrier frequency range, the broadband log-periodic antenna impedance has been optimised to match the SBD, while at the baseband frequency, the receiver was optimised to a 50 Ω output through an impedance transition. These have been key issues for the excellent performance of the compact receiver module over the entire E-band.

A modified wideband bandpass filter based on a bandstop filter is realised using half-wavelength and one-wavelength open-circuited resonators. Six transmission zeros are utilised to obtain the sharp rejection characteristics over a broad stopband. The passband bandwidth can be varied by changing the impedance of the configuration. A compact prototype filter with 27% bandwidth is demonstrated. Without coupling gaps between resonators, the new filter shows low insertion loss and is easy for fabrication. To illustrate the concept, a bandpass filter is designed, fabricated and measured. Simulated and measured results are found in good agreement with each other.

Presented is a highly miniaturised bandpass filter (BPF) with superior passband selectivity and high rejection over a wide stopband for 2.4 GHz WLAN applications. The proposed third-order coupled resonator design with a cross-coupled path provides an attenuation pole that is very close to the passband. Properly setting the fractional bandwidth and the resonator Q factor yields a sharp transition edge to suppress a 2.1 GHz WCDMA signal. Furthermore, the use of quasi-lumped LC resonators reduces the area of the BPF and generates multiple transmission zeros to enhance the desired stopband rejection.

Presented is a WR-3 band (220–325 GHz) waveguide bandpass filter, which is constructed from three offset waveguide resonators operating at TE₁₀₁ mode. This directly coupled resonator filter with Chebyshev response is designed to have a centre frequency of 300 GHz, a fractional bandwidth of 3.3% and a passband return loss of 20 dB. This filter is fabricated using thick SU-8 photoresist micromachining technique and has been tested. The measured average passband insertion loss is as low as around 0.4 dB. The measured return loss is better than 15 dB across the whole passband.

A novel multilayer substrate integrated waveguide (SIW) filter with an improved stopband using mixed coupled modified trisections (MCMTs) is presented. The proposed filter is composed of two cascade MCMTs embedded in LTCC substrate. Four transmission zeros (TZs) can be generated with only three resonators, where two TZs near the passband are utilised to achieve sharper skirt selectivity, and another two TZs for the upper wide stopand. A 10 GHz experimental filter has been designed, fabricated and measured to validate the proposed method.

Presented is endless optical control not only of the state-of-polarisation of an analysed signal and its orthogonal, but also of the phase difference between the two. The normalised Stokes vector space is thereby stabilised, at the polarisation scrambling speeds of up to 20 krad/s.

An improved error code correction algorithm for phase-shifted optical quantisation is presented and experimentally demonstrated. The error probabilities for each valid code are calculated and the invalid codes are corrected by using the maximum likelihood estimation algorithm. The experimental result shows that the spur-free dynamic range of the system has an improvement of 2.28 dB compared to the Hamming algorithm in a 10-GSamples/s, 4-bit resolution all-optical analogue-to-digital converter.

All-optical XOR gates for QPSK signal based optical network applications such as checksum, error recognisation etc., aided by a partially-modulated QPSK signal, are demonstrated through a 10-Gbaud proof-of-concept experiment with power penalty of 4 dB.

A high-performance bulk silicon interdigital capacitive temperature sensor based on graphene oxide (GO) is presented. Compared with typical CMOS integrated temperature sensors, the sensitivity of this bulk silicon interdigital capacitive temperature sensor was improved significantly by using GO as sensing material, and this temperature sensor can operate in the range of − 70 to 40°C.

Mobility coupling effects due to remote Coulomb scattering (RCS) are demonstrated for the first time in FD-SOI CMOS devices subjected to front and back interface electrical degradation. The evolution with stress time of the front and back threshold voltages as well as of the low field mobility values has been obtained. The front and back interface mobility degradations were then correlated to the stress induced interfacial charge variations for each stressed interface. This enabled the clear demonstration of the existence of mobility coupling effects between the front and back interface by RCS through the silicon film.

The effect of parasitic series resistance in the accumulation region has been investigated under the framework of the distributed bulk-oxide trap model. It is shown that while the series resistance may be too small to impact the total capacitance, it can have a significant effect on the total conductance by adding a term ∝ ω ². It leads to a proposal of an extraction method for series resistance. The enhanced bulk-oxide trap model with series resistance as well as dielectric leakage can explain the uncommon conductance frequency dispersion data for an Al₂O₃-InGaAs MOS capacitor with 2.5 nm thin Al₂O₃ layer.

A multichannel spectral surface plasmon resonance (SPR) sensor module which provides self-referencing capability has been designed to inhibit error influences arising from light source instability. The device timely refreshes the light intensity baseline based on periodical scans over several channels. In particular, the scan operation is achieved by changing optical media on the optical path instead of conventional mechanical scanning. Experiments demonstrate that the sensor module achieves a refractive index resolution level up to ∼ 9.3 × 10^{− 7} RIU.

This Letter proposes a combination of target detection and block-matching 3D filter for despeckling SAR images. The proposed method is able to effectively preserve targets, such as the edges and dots of synthetic aperture radar (SAR) images, whilst removing noises. In the first step of our proposed method, based on despekling results of bilateral filtering and edge detection of a canny operator, some targets are detected and removed from an SAR image. The second step uses BM3D for denoising the targets-removed image. Finally, the removed targets are added to the despeckled targets-removed image and desirable results can be achieved.

A novel model for hot-carrier degradation in a lateral insulated gate bipolar transistor (IGBT) device on SOI substrate (SOI-LIGBT) is presented. The setup of the model is based on the existing hot-carrier degradation mechanism in a SOI-LIGBT and assisted by a lateral DMOS device on SOI substrate (SOI-LDMOS) with completely the same structure except for the doping type in the drain area. The model parameters have been extracted by the degradation measurement results and the validity of the proposed model in a SOI-LIGBT has been also verified.

This reported work investigates InGaSb/AlSb p-channel HFETs with hydrogen plasma treatment. The study found that hydrogen plasma treatment can effectively shift threshold voltage from 0.47 to 0 V. A 0.2 µm gate-length device exhibited DC performances of a maximum drain current of 61 mA/mm, and a peak g_m of 83 mS/mm.

A report is presented on a Al/HfN/p-Si(100) n-MISFET with excellent electrical properties that inserts a 4 nm-thick HfN gate dielectric with equivalent oxide thickness of 0.7 nm formed by electron-cyclotron-resonance plasma sputtering. The threshold voltage (V_th) of the device was 0.05 V. The on/off ratio and subthreshold swing at W/L = 90 µm/5 µm were ∼10³ and 200 mV/dec., respectively. In particular, the n-MISFET exhibits I_DS,sat = 20.2 µA/μm and g_m = 20.5 mS/mm. This is the first report of n-MISFET characteristics with HfN gate dielectric.

The multidimensional discrete Fourier transform (MD-DFT) plays an important role in a growing number of signal processing applications. The fundamentals of its applicability as a unitary transform between discrete periodic sequences defined on multidimensional lattices stand on the Hermitian orthogonality of the vectors defining the MD-DFT matrix. A proof of the consistency of the MD-DFT formulation was first provided by Bernardini and Manduchi in 1994 using the Smith normal form theorem of integer matrices. In this reported work, a new proof is provided based on the nullity of the cardinal function on the nonzero cardinal points.

Recently, usable speech criteria have been proposed to extract minimally corrupted speech for speaker identification in co-channel speech. Proposed is a new usable speech extraction method based on the pitch information obtained from a multi-resolution analysis by empirical mode decomposition. The idea is to retain the speech segments that have only one pitch detected and remove the others. Evaluation of this method is performed on the TIMIT database referring to the target to interferer ratio measure. Co-channel speech is constructed by mixing all possible gender speakers. Results do not show much difference for different mixtures. For the overall mixtures 94.97% of usable speech is correctly detected with false alarms of 16.52%.

Proposed is an adaptive fully transmitter-based block-diagonalisation scheme for multiple input multiple output (MIMO) multiuser downlink systems. A relaxation to the beamforming optimisation constraints is proposed, which introduces interference diversity and attains a more efficient performance optimisation. The trade-off to the performance improvement is an increase in the precoding complexity imposed by the adaptive nature of the proposed beamforming. A sub-optimal adaptive-decomposition beamforming scheme is also proposed with a reduced complexity overhead. Comparative analytical and simulation results to conventional beamforming demonstrate the significant diversity gains offered by the proposed scheme.

To exploit distributed computation in wireless sensor networks (WSNs) time synchronisation protocols are required. These protocols support advanced distributed and synchronous tasks between several nodes. Temperature changes have a strong influence in oscillators and may vary the clock of the nodes. The flooding time synchronisation protocol (FTSP) is a common time-sync protocol in WSNs. It cannot deal with rapid temperature changes and needs several long periods to readjust the clock drift. Proposed is an innovative correction factor, implemented in a module called advanced adjustment temperature (A2T), that minimises the impact of temperature in the clock skew. This module may be placed on top of any clock-skew based time synchronisation protocol with minimum coding modifications. For this work, the module has been linked to the FTSP, producing A2T-FTSP. Experiments show that A2T-FTSP reduces noticeably the average synchronisation errors compared to FTSP for the same varying temperature conditions.