An effective way to accelerate the Finite-difference time-domain (FDTD) method is the use of a Graphic Processing Unit (GPU). This paper describes an implementation of the three dimensional FDTD method with CPML boundary condition on a Kepler (GK110) architecture GPU. We optimize the FDTD domain decomposition method on Kepler GPU. And then, several Kepler-based optimizations are studied and applied to the FDTD program. The optimized program achieved up to 270.9 times speedup compared to the CPU sequential version. The experiments show that 22.2% of the simulation time is saved compared to the GPU version without optimizations. The solution is also faster than previous works.

We show how a high-dispersion composite right/left-handed metamaterial leaky wave antenna can be deployed as a compact sensor for localization. The antenna, unlike previous leaky wave scanning antennas, requires only a narrowband frequency stimulation range, 450 MHz for -68 degrees to +27 degrees scanning including broadside for 2-GHz center frequency operation. The antenna is equipped with a detector diode so that homodyne detection of objects in its field of view can be obtained. As the antenna is frequency scanning, spatial location information is additionally presented to the detector. (c) 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1883-1886, 2014

A semi-automatic tool is reported that first analyzes the sequential FDTD program to obtain memory access patterns and related features, and then optimizes the FDTD program with combined use of several types of CUDA memory on both Fermi and Kepler architecture GPUs. The experiments show a 13% and 18% speedup using Fermi and Kepler GPUs respectively compared to the GPU version program without optimization. Up to 142 times speedup is achieved compared to the sequential FDTD C program at a FDTD 3D mesh size of 250* 250* 250 (15.625 million mesh cells) with 10 layers CPML boundary conditions in 4096 time steps.

This paper proposes a hybrid scanning antenna architecture for applications in mm-wave intelligent mobile sensing and communications. We experimentally demonstrate suitable W-band leaky-wave antenna prototypes in substrate integrated waveguide (SIW) technology. Three SIW antennas have been designed that within a 6.5 % fractional bandwidth provide beam scanning over three adjacent angular sectors. Prototypes have been fabricated and their performance has been experimentally evaluated. The measured radiation patterns have shown three frequency scanning beams covering angles from 11 to 56 degrees with beamwidth of 10 ± 3 degrees within the 88-94 GHz frequency range.

This paper proposes a substrate integrated waveguide (SIW) cavity-based method that is compliant with ground-signal-ground (GSG) probing technology for dielectric characterization of printed circuit board materials at millimeter wavelengths. This paper presents the theory necessary to retrieve dielectric parameters from the resonant characteristics of SIW cavities with particular attention placed on the coupling scheme and means for obtaining the unloaded resonant frequency. Different sets of samples are designed and measured to address the influence of the manufacturing process on the method. Material parameters are extracted at V - and W -band from measured data with the effect of surface roughness of the circuit metallization taken into account.

The Kyoto Protocol and the European Energy Performance of Buildings Directive put an onus on governments and organisations to lower carbon footprint in order to contribute towards reducing global warming. A key parameter to be considered in buildings towards energy and cost savings is its indoor lighting that has a major impact on overall energy usage and Carbon Dioxide emissions. Lighting control in buildings using Passive Infrared sensors is a reliable and well established approach; however, the use of only Passive Infrared does not offer much savings towards reducing carbon, energy, and cost. Accurate occupancy monitoring information can greatly affect a building's lighting control strategy towards a greener usage. This paper presents an approach for data fusion of Passive Infrared sensors and passive Radio Frequency Identification (RFID) based occupancy monitoring. The idea is to have efficient, need-based, and reliable control of lighting towards a green indoor environment, all while considering visual comfort of occupants. The proposed approach provides an estimated 13% electrical energy savings in one open-plan office of a University building in one working day. Practical implementation of RFID gateways provide real-world occupancy profiling data to be fused with Passive Infrared sensing towards analysis and improvement of building lighting usage and control.

The control of artificial lighting is a key parameter to be considered in buildings towards energy and cost savings. Efficient, need-based control of building lighting through occupancy detection using Passive Infrared (PIR) sensors has become a reliable and well established approach. However, the use of only PIR sensors for occupancy monitoring does not offer much savings and depends upon a building's type and use, and its occupancy levels. Accuracy of occupancy monitoring greatly affects building lighting control strategy and hence, percentage savings. Besides considering lighting control based on occupancy detection using PIR sensors, this paper presents a data fusion approach of passive RFID based occupancy monitoring with PIR. The proposed methodology provides an estimated 13% of electrical energy savings in one open plan office of a University campus building. Practical implementation of RFID gateways provide real-world occupancy profiling data to be fused with PIR sensing towards analysis and improvement of building lighting usage.

This paper introduces an Integrated Sensor Information System (ISIS) and outlines the study and use of Radio Frequency propagation and power distribution internally from a bus to an external receiver. A study on scaled model of a single decked bus, examining the effect of antenna placement and internal structures within the bus on the propagation and power distribution of an omni-directional source is performed. Measurements on the scaled bus model was performed in a fully automated near field scanner and the results are discussed.

Integrated Sensor Information System (ISIS) is an intelligent sensor system which when installed in a public bus transport system, will detect potential criminal threats and relay live information gathered from audio/visual/RF sensors to a central control point through mobile wireless technology. ISIS will use iBurst™, a Mobile Broadband Wireless Access technology classified under the IEEE 802.20 standard. This paper outlines the study of iBurst™ and its application with ISIS. A study on the propagation characteristics of iBurst™ through simulations with a ray tracing software and through measured data was performed and a comparison is laid out between the Simulated and measured results. The accuracy of the deterministic ray tracing model is validated for iBurst™.

A frequency selective surface (FSS) which exploits the dielectric anisotropy of liquid crystals to generate an electronically tunable bandpass filter response at D Band (110-170 GHz) is presented. The device consists of two printed arrays of slot elements which are separated by a 130-mum thick layer of liquid crystals. A 3% shift in the filter passband occurs when the substrate permittivity is increased by applying a control signal of 10 V. Measured results show that the insertion loss increases from -3.7 dB to -10.4 dB at resonance (134 GHz), thus demonstrating the potential to create a FSS which can be switched between a transmitting and a reflecting structure.

A detailed analysis of mode structures inside coupled microstrip lines and their correlation with crosstalk between traces has been performed. The use of finite-difference time-domain and singular value decomposition methods for modal identification followed by cross correlation for crosstalk prediction is demonstrated in this paper. The combination of these methods is robust, versatile and ideal for pulsed applications in an inhomogeneous, anisotropic multi-layer substrate with complex 3D structures. Moreover, all possible modes are extracted in a single analysis. This novel approach provides a quantitative measurement of crosstalk by establishing correlation between modes evolving inside the source line and the field waveforms coupled with the victim line. To our knowledge, this is the first time such a study has been performed. The effects of line topology and pulse characteristics are examined. At the early stage of pulse evolution, the TEM mode of the source line dictates coupling, however, as the pulse advances the higher-order TM mode dominates and exhibits significant contribution to the evolution of the waveform coupled with the victim line which is confirmed by cross-correlation. This study has physical significance in devising systems for suppressing unwanted modes responsible for crosstalk and radiation leakage due to UWB pulses.

The interaction of ultra-wideband pulses propagating on a semiconductor substrate is analysed without solving the charge dynamic equations. This study demonstrates the systematic approach for selecting semiconductor parameters and their significance in the practical design of high speed microstrip interconnects. To our knowledge, this is the first time such a comprehensive and conceptual study of EMP interaction with semiconductor dielectrics has been performed. The comparison of waveforms on single and coupled lines elucidates the mechanisms of pulse distortion on semiconductor substrates. However, the realization of the dielectric relaxation is studied by changing the doping concentrations of the substrate. Moreover, the evolution of currents for different conductivities illustrates the realization of the doping concentration in a semiconductor. Furthermore, the study on layered substrates with different doping concentrations and relative permittivities demonstrates the fidelity of waveforms on the source line and significantly weak coupling to the victim line. This analysis is a first step towards the full-fledged self- consistent simulations of EMP interaction with the physical model of semiconductor devices. A 160 node Itanium II cluster processor has an average 5 hours simulation time in this work.

Self-consistent 3-D FDTD analysis of a bounded-wave EMP simulator with a human model in the presence of a complex electrical environment is performed. The designed EMP simulator could be directly applied to the optimization of EMP for a desired level of the field intensity and risetime in UWB pulsed applications. Using a fine mesh and an Itanium II 160 processor cluster allowed the risetime of 1.4 ns - very close to the experimental design of 1 ns. This study is significantly important for investigating the effects of intense UWB pulses on biological cells. A detailed analysis from the point- of-view of physical understanding the effects of EMP on human tissue is presented. The biological cell of high conductivity i.e. small relaxation time inducing minimum field inside the human body is studied. A detailed picture of electric field and current evolution is demonstrated.

Measurement of broadband substrate permittivity with temperature is reported making use of special calibration routines for post-processing of measured results. The LRRM method is used for frequency coverage in the range 50 MHz to 110 GHz using 100 mum GSG probes. Predictive software has been integrated with the existing measurement control package to achieve semi-automatic material characterisation

The use of carbon fibres in composite materials is reported for laminate materials used in electronics packaging. The effective medium theory is described for this application and used to estimate the effective complex permittivity of the laminate and hence produce a theoretical shielding effectiveness for the material. To validate this work experimental methods are discussed using the waveguide simulator technique. Agreement between simulation and measurement is very good

A low cost substrate material is reported using a polypropylene and nanoclay powder composite. The material characteristics, such as dielectric constant, loss tangent, lamination and thermal properties have been determined. A patch antenna has been fabricated using the developed substrate material and its performance has been characterized

The shielding properties of carbon fibres in composite materials are compared for two particular lamination examples used in avionics. Plane wave shielding theory and effective medium theory are compared in this work and found to provide the same theoretical shielding level. Measurements have been performed on samples at both X-band and S-band providing shielding effectiveness greater than 70 dB. This work has found that reflection is the main shielding mechanism for this particular type of carbon fibre composite material. Measurements have also been performed on reduced thickness laminates to test the simulated results. This also provided up to 70 dB of shielding across the measured frequency band.