To clarify radio propagation characteristics and the mechanism for vehicle-to-vehicle communications in urban areas, this study presents a PML implementation using approximation in the high-frequency band as an elemental technology. We evaluated the PML absorption performance and clarified that the proposed method is applicable to large-scale analyses.

Performance suveyrance of CPML (Convolutional PML) for FDTD (Finite-Difference Time-Domain) method in cylindrical coordinate system was carried out. The CPML was placed perpendicularly to the radial axis and designed to absorb diverging or converging waves. To be able to analyze microstructured optical fibers and disk/ring resonators we introduced finite axial wavenumbers into the FDTD formulation. We investigated the dependence of reflectivity upon CPML's constituteve parameters such as $kappa$ and $sigma$ for various curvature radii and the axial wavenumbers. As a result of evaluation we found that the reflectivity gradually increased togather with the increase of the wavenumber. We also confirmed that the absorption performance was of the similar order for the converging waves and the diverging ones provided that their curvature radii were the same.

We present an improved perfectly matched layer (PML) for the analysis of plasmonic structures, based on the manipulation of PML parameters. Two different types of stretched coordinate PML are employed sequentially in the spatial domain: a real stretched coordinate PML to increase the effective buffer space around plasmonic structures and a complex stretched coordinate PML to absorb outgoing waves and terminate the computational domain. Numerical examples show that a significant increase in computational efficiency is obtained because the proposed PML can be placed closer to plasmonic structures than the regular PML without affecting the field distribution of bound modes.

Making up an electromagnetic wave simulator based on the FEM is tried, which may run on some widely used platforms by use of Java and a single commercial tool. Since the codes and configuration files to be created for this simulator are common, one can construct the simulator running on the platforms at the same time. Using this simulator, the transmission properties of two- and three-dimensional waveguide discontinuities in optical and microwave waveguides are analyzed, the inverse problem in material constant measurement is solved, and the computed results are presented including plots of the electric field distribution.

Improvement of the absorbing boundary conditions for triangle-hexagonal dual cell grids in the time domain method is described in this paper. The magnetic field components, which are evaluated by the electric fields at the circumcenters of the triangle cells, are conformed to Berenger's perfectly matched layer absorbing boundary conditions. The electric field is linearly interpolated by the fields at the vertices. The lower reflection coefficients in the frequency range for the equilateral and non-equilateral triangle cells are demonstrated.

We have proposed an algorithm to apply perfectly matched layer (PML) absorbing boundary condition to the noncubic cell time-domain method. The extended method has a merit of flexibility in truncating the computational domain by the use of a curvilinear PML. In this paper we apply a circular PML for computing the scattered fields of a dielectric cylinder or cylindrical shell of arbitrary cross section shape. Numerical results are presented to demonstrate the accuracy of this method.

The recently proposed modified PML (MPML) absorbing boundary condition is extended to three dimensions. The performance of the MPML is investigated by FDTD simulation of a typical microstrip line and a rectangular waveguide. The dominant and higher order modes of the microstrip line and the waveguide are excited separately in the computation. In all of the cases of excitation, the reflection properties of the MPML boundaries are examined for the side walls and the end walls, respectively. Various values of the permittivity and permeability of the MPML medium are tested in the computation, and the variation behavior of reflection from the MPML boundaries is examined. The numerical results reveal that by choosing appropriate values of the permittivity and permeability of the MPML, we can realize efficient absorption of both evanescent waves and propagating waves over a wide frequency band.

A rigorous analysis of coupling between two twin-slot antennas using the Finite Difference Time Domain (FDTD) method is reported for the first time. The Phase Cancellation Effect (PGE) is used to reduce the coupling due to the TM0 surface wave mode between the Coplanar Waveguide (CPW) fed cascade-connected twin-slot antennas. To confirm the effectiveness of this approach, coupling between single-slot and twin-slot elements separated by λ0/2 was analysed. The coupling between the two single-slot antennas was S21 = -30.2 dB. For the case of two twin-slot antennas, the coupling was found to be -37.8 dB, 7.6 dB below that of the single-slot antennas. The phase cancellation effect of surface waves is significant in reducing coupling between two twin-slot antennas, in addition to minimising power loss into substrate modes. A memory optimised implementation of the FDTD method with the Berenger Perfectly Matched Layer (PML) Absorbing Boundary Condition (ABC) was used for the numerical analysis.

This paper is concerned with a point-oriented finite volume time domain (FVTD) method in the Cartesian coordinate system for analyzing electromagnetic wave scattering by arbitrary shaped metallic gratings. The perfectly matched layer (PML) is used for the absorbing boundary conditions (ABC's) in the directions corresponding to transmitted and reflected wave regions. An FVTD version of the Floquet's theorm is described to impose the periodic condition in the direction where conducting rods are located periodically. The boundary conditions for a conductor rod which is not well suited to the Cartesian coordinate system are satisfied in an average fashion by introducing image fields at image points. It is shown that the present method gives accurate numerical results. Numerical calculations are also carried out for thick conducting rods which seem difficult to deal with in an analytical way.

This paper is concerned with a point-oriented finite volume time domain (FVTD) method in the Cartesian coordinate system and its application to the analysis of electro-magnetic wave propagation in a bended waveguide as well as radiation from and receiving by a horn antenna with a flange of arbitrary angle. The perfectly matched layer (PML) is used for the absorbing boundary conditions (ABC's). The boundary conditions for a perfect conductor not well suited to the Cartesian coordinate system are also proposed. According to this algorithm, the boundary conditions are satisfied in an average fashion at the conductor surface without changing the computational scheme. In this sense, numerical computations based on the present method are simple but flexible. Numerical results show good convergence.