The current practice for designing antennas over artificial magnetic conductor (AMC) is time and labour intensive. A novel methodology is described for saving time and effort in designing such antennas. The proposed method is based on using conductive fabric as a radiating element. The method is validated via the design of a textile dual-band monopole antenna on AMC covering both WiFi and the 4G long term evolution (LTE) frequency bands.

A planar super-wideband (SWB) antenna fed by an asymmetric coplanar strip is proposed, fabricated, and tested. The antenna consists of a hexagonal loop strip in which a signal strip is prolonged, curved, and shorted to a ground plane to facilitate SWB characteristics. In addition, by adding a boomerang-shaped strip to the ground plane, the effective electrical length is increased, thereby decreasing the lowest operating frequency. The simulated results show that the proposed antenna exhibits a −10 dB reflection bandwidth from 1.18 to 49.22 GHz corresponding to a ratio bandwidth of 41.7:1. The measured results of the fabricated antenna are also represented and compared with the simulated results. The antenna gain changes from 2.05 to 10.62 dBi within the measured frequency range.

A cost effective low temperature co-fired ceramics antenna with wide beamwidth and high gain at 77 GHz is presented. This antenna consists of an aperture coupled dielectric resonator antenna which provides high gain and wide beamwidth. The vias surrounding the dielectric resonator act as a metallic fence, and prevent signal leakage. The top surface of this antenna is covered with dielectric layer, and no metal pattern was exposed to the air. Fabrication cost can be reduced by eliminating the expensive gold plating process due to this top passivation layer. The simulated results of the proposed antenna show a wide beamwidth of 86° and a peak antenna gain at 76.5 GHz of 7.5 dBi.

A frequency tunable liquid metal antenna that can compensate for hand effects is presented for use in mobile phones. The antenna structure is based on a planar inverted-F antenna, which is frequently considered as an internal antenna. The upper arm of the antenna was formed using liquid metal filled in a Teflon tube. The liquid metal used was Galinstan. The length of the filled portion determined the resonant frequency of the antenna. The tuning capability of the antenna was demonstrated through an automatic tuning experiment, in which the resonant frequency of the antenna was automatically recovered from disturbances caused by a human hand being placed in the proximity of the antenna.

A planar printed multi-input–multiple-output (MIMO) antenna with pattern diversity is proposed. The two printed dipole-like radiators have omnidirectional radiation patterns in the orthogonal planes. The antennas are printed on the opposite sides of a dielectric substrate, which makes it a compact MIMO system with excellent isolation between the antenna elements. With an external loaded capacitor, the MIMO antenna shows a wide frequency tunable range.

A two-transistor and two-magnetic-tunnel-junction (MTJ) multi-level cell (MLC) structure of spin-transfer torque magnetic random access memory (STT-RAM) is proposed. Compared with the conventional one-transistor and two-magnetic-tunnel-junction MLC STT-RAMs, by adding an extra access transistor and adjusting the connection of the two MTJs, the extra write power consumption on the soft bit MTJ can be reduced, which will also have a benefit to the lifetime of the soft bit. Specifically, the simulation results show that more than 75% write power consumption on the soft bit can be wiped out, and the area cost caused by the extra access transistor is negligible.

A simple and cost-effective technique is proposed for jitter and noise separation in ADC test. On the basis of the property that clock jitter is modulated by the slope of input signal, few simple mathematical manipulations are performed on a single data record of ADC output to separate jitter and noise. The proposed method requires only one high-frequency signal test and eliminates the need for a second low-frequency test in conventional dual-frequency jitter tests. Compared with existing single-frequency test, the new method is accurate and robust to non-harmonic distortion, without requiring any additional data acquisition time. Therefore, both hardware overhead and data acquisition time are saved significantly. Experimental results show that both jitter and signal-to-noise ratio are estimated accurately, and the accuracy of jitter estimation is comparable with that of conventional dual-frequency test.

A probabilistic solution of the time-domain performance of an arbitrary switching circuit driven by a generalised random switching sequence is presented. A generalised random switching sequence is the superset of all clock-based random pulse-width modulation schemes and has the best possible spectral spreading. The switching circuits considered are linear and time invariant, have a constant DC input and contain at least one ideal switch. The mean of the probability density updates exactly like a discrete time solution to state-space averaging, with probability replacing the duty cycle. The covariance matrix of the probability density updates using a difference equation. The value of this work is in the prediction of the statistics of transients for randomly switched power converters. A boost converter is presented as an example.

A near-threshold all-digital phase-locked loop (ADPLL) with a power management unit (PMU) is presented to make the proposed ADPLL work reliably across variations and power consumption as well is reduced. When operated under near-threshold condition from 0.52 to 0.58 V V _DD, the gated digitally controlled oscillator frequency range is from 90.8 to 245.7 MHz. When the ADPLL is operated at 0.52 V V _DD, a lock-in time of 9.5 μs at 100 MHz output clock frequency is measured with an rms period jitter of 0.17% UI. With the PMU, the ADPLL power reduction at 130 MHz output frequency is 39% and the buck converter power consumption is nearly 30 μW. Consequently, the proposed ADPLL with PMU is suitable to event-driven or low-voltage applications.

Existing power allocation schemes for single-carrier frequency division multiple access (SC-FDMA) systems are based on the assumption of Gaussian inputs. However, in practical systems, the inputs belong to a set of finite symbol alphabets. In this reported work the power allocation problem in the uplink SC-FDMA system with arbitrarily distributed finite power inputs is considered. An optimal solution to the problem is found by using the relationship between minimum mean-square error and mutual information. Simulation results show that solution allocates power in accordance to the modulation scheme employed and achieves significant power saving compared to schemes that assume Gaussian inputs.

As the computing power of mobile/wearable devices increases, computation-intensive real-time optical character recognition (OCR) becomes feasible for high-resolution images. Developing mobile/wearable OCR applications is challenging because they should perform highly accurate OCR within users' tolerable waiting time and achieve low energy consumption. An adaptive power management scheme is presented that predicts the execution time for OCR and minimises its energy consumption via dynamic voltage and frequency scaling while meeting its time constraint. Tesseract, a popular open source OCR engine, is used to verify the proposed scheme. The experimental results show up to 48.25% reduction in energy consumption (with an average reduction of 34.53%).

The main aim of this reported work was to design new selective cascaded-integrator-comb (CIC) filter functions. The theoretical design equations and impulse response coefficients, as well as the frequency response characteristics of the novel filter functions are presented. Compared with existing filter functions in the literature, the proposed functions not only have improved insertion loss but also a multiplierless architecture, better passband characteristics and lower impulse response coefficients.

Families of irreducible polynomials over 𝔽 _p , p odd are provided, where pth roots can be efficiently computed. Efficient cube root computations in extensions of characteristic 3 have been recently studied, in part motivated by pairing cryptography implementations. For the particular case p = 3, some previous results are slightly improved and new extensions are provided where efficient cube root computations are possible.

Single-error correction, double-error detection (SEC–DED) codes are a type of error-correction codes widely used in electronics to protect memory devices from data corruption. Odd-weight-column SEC–DED codes are a type of these codes where the parity-check matrix is built with every column including an odd number of ones. With this approach, double errors have an even-weight syndrome and can be differentiated from single errors and, consequently, easily detected. There are applications, such as avionics or space, where a multiple error usually affects adjacent cells. Adapting SEC–DED codes to protect against triple-adjacent errors is interesting in these applications. A modification to existing odd-weight-column SEC–DED codes to add triple-adjacent error detection (TAED), creating SEC–DED–TAED codes, is presented. The implementation of the additional triple-adjacent detection logic for these codes can be performed with limited performance and area overhead.

The effects of joint hardware impairments on the performance of fixed-gain amplify-and-forward (AF) relaying are studied. By considering IQ imbalance at the source and destination and the nonlinear relay the outage probability over Nakagami-m fading channels is derived, and the effects of fading and hardware impairments on the system are analysed. The analytical results are verified by Monte Carlo simulations.

New coplanar waveguide bandpass filters with controllable transmission zeros (TZs) have been developed by using separated electric and magnetic coupling paths. Either magnetic-dominant coupling or electric-dominant coupling generates a TZ, but different positions. Filter TZs are attributed to the electromagnetic couplings, and the additional coupling resonators are not required. The new designs have been demonstrated by an experiment. Advantages of the proposed filters are not only their simple and compact circuit topologies, miniature circuit sizes, but also their controllable TZs without requiring via hole.

An innovative theory on the passive circuits capable to generate low-pass negative group delay (NGD) behaviour is introduced. An identification method enabling to identify the first-order NGD simple cells built with resistor-inductor (RL)- and resistor-capacitor (RC)-networks is elaborated. The fundamental characteristics as the NGD level and cut-off frequency are formulated from the low-pass NGD circuit canonical transfer function. The NGD existence conditions are derived in function of the established topology parameters. Despite the attenuation systematically related to the passive cell nature, low-pass NGD behaviours with tens ns NGD level and tens MHz bandwidth were obtained with an example of lumped RL-network-based L-topology circuit. Transient analysis was performed to illustrate that the NGD phenomenon enables to exhibit baseband signal advance effect. The proposed NGD topology simplicity promises their potential applications especially in term of signal correction and the modern electronic system improvement.

A broadband out-of-phase power divider in a compact structure employing a microstrip technology is presented. The proposed power divider consists of a T-junction of microstrip to slotline transition at the input ports along with a pair of tightly coupled microstrip lines at the two output ports. The main features of the proposed device are the employment of a dumbbell-shaped slot terminated with a chip resistor under the tightly coupled lines to improve the isolation between the output ports and shunt open-ended stubs at the output ports to improve their impedance matching. The overall size of the structure is 30 × 60 mm using the substrate Rogers RO4003C with a dielectric constant of 3.38 and thickness of 0.4 mm. The simulated and experimental results of the developed device show wide bandwidths (120% fractional bandwidth) with isolation >15 dB across the investigated band 1–4 GHz. In addition, the output ports are out-of-phase with <1° phase imbalance across the whole frequency band.

An optoelectronic integrated circuit (OEIC) in a 0.35 μm BiCMOS technology is presented. The receiver designed for optical wireless communication and communication over plastic optical fibre for data rates up to 2 Gbit/s has a 200 μm diameter avalanche photodiode (APD). Thanks to a thick intrinsic zone the APD has a low capacitance of 0.5 pF. The chip requires a supply voltage of 3.3 V and has a current consumption of 76 mA. The OEIC provides a single-ended output swing of 550 mV on 50 Ω and a total transimpedence of 260 kΩ with a bandwidth of 1.08 GHz. The OEIC achieves a sensitivity of −32.2 dBm at a BER of 10⁻⁹ for a data rate of 2 Gbit/s.

A self-seeding wavelength division multiplexing passive optical network scheme employing a directly modulated reflective semiconductor optical amplifier at 1.25 Gbit/s is investigated, aiming long-reach applications. Specifically, power penalty and bit error rate (BER) were measured as a function of the fibre length for downstream path. Optical transmission over 140 km, within the forward error correction limit (BER of 10⁻⁴), with a maximum power penalty of 2.7 dB is experimentally demonstrated. In contrast, a pre-spectrum-sliced source (PSSL) topology displays a similar penalty but its maximum reach is restricted to 80 km. Thus, the proposal enables an enhancement of 12 dB on power budget when compared with the PSSL topology, as well as eliminates the need for a shared broadband light source.

A hardware-efficient adaptive algorithm for frequency offset and phase noise mitigation in coherent optical quadrature amplitude modulation systems is presented and analysed. Hardware efficiency for the mitigation of imperfections is achieved by computing directly the complex exponential, thus avoiding a CORDIC processor in the phase recovery loop. The design includes a square-root- and trigonometry-free update. Simulation results substantiate the theoretical findings.

Colour shift keying (CSK) can achieve significant performance gains in multi-colour visible light communications (VLCs). Existing CSK constellations are designed within the positive domain which satisfies the requirement of non-negative optical intensity modulations. A scheme is proposed to incorporate spatial modulation with a CSK design by grouping LEDs. In this way, the CSK constellation is optimised within the entire real domain and hence achieves a larger minimum Euclidean distance so as to enhance the bit error rate (BER) performance. Simulation results show a noticeable performance gain by the proposed scheme compared with traditional CSK under ideal light-of-sight optical channels. Further, by experimental tests, an even more pronounced BER gain is achieved by the proposed scheme over real VLC channels.

The study, design and measurement of a continuous time analogue equaliser based on a differential cascode amplifier cell, using indium phosphide double heterojunction bipolar transistors (DHBTs) reaching an f _T/f _max of 370/340 GHz are reported. A bandwidth of more than 110 GHz is achieved and a peaking of 18 dB at 95 GHz is reached. Simulations demonstrated an equalisation at 205 Gbit/s. This is believed to be the highest frequency peaking reported to date.

A high-performance current-mode, multi-input winner-take-all maximum circuit is introduced. Owing to low-impedance low-capacitance input nodes involved, the speed of the new circuit is higher than major counterparts. Simulation results show that the new circuit exhibits superior performance compared with well-known rival counterparts in terms of speed, area, dynamic range and power dissipation.

Technology scaling results in that, soft errors, due to radiation-induced single event double-upset (SEDU) that affects double nodes through charge sharing, become a prominent concern in nanoscale CMOS technology. Existing hardened schemes suffer from being not fully SEDU-immune, or perform with too large cost penalties regarding propagation delay, silicon area, and power dissipation. A novel high-performance, low-cost, and fully SEDU-immune latch, referred to as HSMUF, is presented to tolerate SEDU when any arbitrary combination pair of nodes is affected by a particle striking. The latch mainly consists of a clock gating-based triple path DICE and a multiple-input Muller C-element. Simulation results demonstrate the SEDU-immunity and a 99.73% area–power–delay product saving for the HSMUF latch, compared with the SEDU fully immune DNCS-SEUT latch.

A simple circuit that is able to indicate if an injection-locked oscillator is in the locked condition by providing a ‘high’ or ‘low’ output is presented. The detector is compatible with most injection-locked oscillators as all that is required is access to the low-frequency bias circuit, with no direct access needed to the RF/microwave signals. To prove the universal nature of the lock detector it is successfully demonstrated practically for two scenarios: (i) a 1 GHz injection-locked VCO and (ii) a 60 GHz SiGe VCO MMIC.

The electromagnetic interference (EMI) caused by alternating current driven LEDs which are widely used as indicator lamps in power strip is presented. The frequency-domain measurement results show that the EMI will violate the MIL-461E/RE102 standard limit line in the electromagnetic compatibility anechoic chamber. The time-domain measurement results show that the breakdown of LEDs suddenly increase the current causing the interference. The colour light of LED is determined by the energy bandgap of the semiconductor, as they may influence the EMI level, red and yellow LEDs are analysed.

The switching frequency of inductive power transfer may change along with the air gap between two coils due to mutual inductance variation. The mutual inductance is conventionally estimated through experimental measurement or finite element analysis. To simplify this process, a frequency-gap model for series–series compensated inductive power transfer is proposed to calculate the unity-gain frequency based on known air gap and coil geometric parameters. Neumann's formula is applied to compute the mutual inductance of the primary and secondary coils. The experimental results show that the unity-gain frequency can be predicted with varying loads and air gaps (75–250 mm), and a demonstrated unity-gain error of <6%.

Asymmetric AltBOC modulation and its unequal power generalised form are proposed to multiplex three QPSK signals on two sidebands. The new constant envelope modulations provide a solution to dual-frequency constant envelope multiplexing problem confronted by BeiDou B2 signals.

An efficient parameter estimation method is proposed for manoeuvring targets with arbitrary parameterised motion. The core idea of the proposed method is based on a derived operation, namely, iterative scaled parametric correlation operation (ISPCO), which can directly present the two highest-order Doppler spread parameters in the two-dimensional parameter domain. By jointly applying ISPCO and dechirping operation, the motion parameters of different orders can be estimated iteratively without searching operation. The proposed method not only is computationally efficient, but also can achieve higher estimation accuracy and lower signal-to-noise ratio threshold than the popular methods based on recursive phase differentiation. Simulation results verify the validity of the proposed method.

Orthogonal frequency division multiplexing multiple-input multiple-output (OFDM-MIMO) radar has different frequencies for different array elements’ transmitting signal. To a same moving target, different array elements obtain different Doppler frequencies. Hence, coherent integration gain of all array elements cannot be obtained if using traditional fast Fourier transform to process radar echo. Proposed is the scale-transform discrete Fourier transform algorithm for achieving Doppler frequencies focus, thus coherent integration of different array elements and a higher processing gain for moving target detection can be achieved.

To extract the coupling capacitance between any two neighbouring through-silicon vias (TSVs) in three-dimensional integrated circuits, most publications use the relation between the inductance matrix and the capacitance matrix (per unit length). However, this relation is based on a homogeneous surrounding medium assumption. It is shown that the previous assumption is inaccurate due to the fact that each TSV is actually surrounded by a non-homogeneous medium (silicon and silicon dioxide materials). The theory behind this claim is provided and validated using ANSYS Q3D. The percentage error in coupling capacitance between the Q3D extraction results and the homogeneous medium model results can reach 70%.

A high-speed transimpedance amplifier (TIA) implemented in 0.13 μm SiGe BiCMOS with a novel bandwidth and power consumption tuning approach is presented. By tuning the circuit bandwidth continuously from 61.6 to 12.8 GHz during runtime, the power consumption of the main amplifier can be reduced by a factor of around 5. Leading to a power consumption reduction of 40% for the TIA core. Despite the power reduction the gain is kept constant at 69.8 dBΩ by utilising field effect transistors as steerable resistors. The high maximum bandwidth admits data rates up to more than 88 Gbit/s with a power consumption of only 78.1 mW. This yields to a very good energy efficiency of 0.888 pJ/bit and a very high gain bandwidth product of 189.8 kΩGHz at the same time. The mentioned performance parameters in conjunction with the bandwidth and power consumption scalability make the TIA well suited for energy-efficient high-speed optical interconnects, e.g. in future high performance computing platforms.

Analysis of MOSFET gate induced transient noise simulation accuracy was performed and the limitation on accurately estimating MOSFET noise performance in the high frequency wireless communications region was identified, validating transient noise simulation against AC noise. The gate noise source is the only one that increases with frequency and this behaviour cannot be simulated accurately using SPECTRE/RF. To enable the design community to accurately simulate gate induced noise in nonlinear circuits, a simple and practical methodology to overcome this limitation is provided, using a highpass filtering-based white noise source approach.

AlInN/GaN high electron mobility transistors fabricated with the semi-insulating barrier layer was investigated to reduce the gate leakage current. The gate leakage current was obtained to be as low as 4.1 × 10⁻⁴ mA/mm at the gate bias of −10 V owing to the use of higher and thicker potential barrier of Mg-doped AlInN.

An enhanced block acknowledgement (BlockACK) method for the aggregate MAC protocol data unit (A-MPDU) transmission is proposed. In the proposed method, the position information of each aggregated subframe is carried by the A-MPDU using the reserved bits and a novel position information control is used to acknowledge the A-MPDU. By utilising the enhanced BlockACK method, the aggregation level of the A-MPDU transmission will not be constrained by the effect of lost subframes. Theoretical analysis and simulation results demonstrate that the enhanced BlockACK method can achieve a more stable aggregation level and higher throughput than the conventional one.

An anti-jamming scheme on the base band instead of the intermediate frequency (IF) is proposed to improve the anti-jamming capability of direct-sequence spread-spectrum (DSSS) receivers. For time–frequency domain technology, both the residual jamming energy and the unexpected loss of signal energy resulting from inaccurate jamming rejection would reduce the capability of signal acquisition. The scheme of detecting jamming by FFT and rejecting jamming by notch filters on the base band is exploited to improve the accuracy of jamming rejection. Monte Carlo simulation results show that the proposed scheme could enhance the anti-jamming capability of DSSS receivers.

The study of various communication networks has attracted many researchers from various academic fields in recent years. It is a major research to identify the faulty links in communication networks. A dependent failure approach is presented to identify the faulty links in wireless communication networks. The node importance evaluation is introduced to overcome the limitations of traditional independent failure methods. Faulty nodes effect on their direct links in the network. The dependent failure topology graph (DFTG) model and faulty link identification method take into consideration the failure probability of different nodes. The management node can autonomously identify, in real time, the most probable failed network links through building the DFTG model. Experimental validation and actual application are carried out separately. The identification method of faulty links applies to satellite networks with the connection-oriented network structure. From the simulation analyses and the actual satellite network, the test results demonstrate that this proposed method is valid, efficient, and suitable for wireless communication network applications.

The time of arrival (ToA) and received signal strength (RSS) estimation errors are modelled based on channel measurements in a non-line-of-sight indoor environment. It is found interesting that their errors are largely independent. Suboptimal hybrid ToA/RSS ranging estimators are derived in closed form based on the obtained error models, and shown to achieve near-optimal performance. The performance of all the estimators improves as the bandwidth increases.

Efficient data-forwarding strategies for wireless sensor networks with a mobile sink which visits rendezvous points (RPs) to gather data from sensor nodes are proposed. With the first proposed strategy, selections of the RP nodes and the final routing paths are based on the latest information of the already selected RP nodes. The second proposed strategy adopts a simpler RP node- and routing path-selection algorithm with the same level of complexity of an existing algorithm. Numerical results show that both of the proposed strategies result in more efficient energy consumption and reduce forwarding hop counts compared with the existing algorithm.