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Segmented antennas loaded with reactance elements at the junctions between segments provide additional parameters for shaping antenna characteristics. The design procedure consists of first, circuit analysis of the multiport antenna description to determine the initial values of the lumped element reactances and second, of fine tuning the antenna dimensions full-wave simulation software. Measured results show that a good matching and an omnidirectional radiation pattern in the vertical plane is maintained up to θ = 70° with a circular ground plane of 1m diameter. [ABSTRACT FROM AUTHOR]

The analogous relationship between the design parameters of offset parabolic reflectors and offset reflectarrays is delineated. Each antenna is specified with four design parameters that best describe the system setup, and the mathematical relationship between the design parameters of these two antenna systems are determined. The presented study allows one to determine the analogous reflectarray system based on the design parameters of the offset reflector and vice versa. This makes it possible to simplify the configuration setup in offset reflectarrays using a coordinate system and a set of parameters that is very suitable for reflectarray design and analysis. [ABSTRACT FROM AUTHOR]

Surface impedance boundary condition (SIBC) is a potential way to improve the efficiency of the finite-difference time- domain (FDTD) method. However, it is still seldom used in FDTD simulations, especially for complicated problems. In this study, the authors propose a novel SIBC, the perfect electric conductor (PEC) backed SIBC (PEC--SIBC). It is a combination of SIBC and PEC. This character makes it possible to integrate PEC--SIBC with the conventional FDTD method. The authors derive the updating equations of PEC--SIBC for a one-dimensional (1D), 2D and 3D problems. Then, the authors verify the validity of PEC--SIBC with a 1D example and analyse the complexity with a 2D example. The comparison for a 1D configuration indicates that PEC--SIBC is a little more accurate than the traditional SIBC. For a 2D example, the SIBC is used to replace a lossy dielectric medium located in the middle of the problem domain. The complexity analysis indicates that PEC--SIBC is much easier and more practical to use than the traditional SIBC. [ABSTRACT FROM AUTHOR]

We present a MATLAB based finite difference time domain (FDTD) method accelerated using the GPU functions in MATLAB's parallel computing toolbox (PCT). Procedures to achieve significant speedups over a CPU implementation of the same code are outlined. The use of specialized code with NVIDIA's compute unified device architecture (CUDA) programming results in impressive computational speedups. However, this requires specialized programming knowledge to efficiently implement. The MATLAB PCT can be applied directly to pre-existing MATLAB FDTD code and obtain reasonable speedups over equivalent CPU code. We demonstrate several modifications to increase the efficiency on several different NVIDIA graphics cards. Benchmarks are presented on problems of practical size (millions of cells) with a CPML terminated domain. [ABSTRACT FROM AUTHOR]

In this paper, a speeding up technique for the lossy anisotropic (Lossy-ANI) algorithm integrated into the finite-difference time-domain (FDTD) method is proposed. The speeding up technique provides remarkable reduction in the computation time of the Lossy-ANI algorithm. This algorithm is applied to a line-fed microstrip patch antenna (MPA) with anisotropic substrate and a lossy anisotropic scattering object. Numerical results show that the anisotropy effects the resonant frequencies of the MPA and the bistatic RCS of the scattering object. [ABSTRACT FROM AUTHOR]