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A modified formulation for fringe component of diffraction coefficient is implemented to TD-EEC method. An example of diffraction by perfectly conducting plate is used to illustrate our scheme. Comparing with the FDTD results we observe that the improved expression for fringe component is more accurate than that of Michaeli's formulation. This high frequency time domain technique is available for treating the bistatic scattering problems for millimeter waves.

The transient feeding to parallel-plate transmission lines from coaxial line is optimized by using the Finite-Difference Time-Domain (FDTD) method and a simple FDTD feed model. Observing the reflected voltages, this letter presents the optimal feeding position and ratio of width to height for a given input impedance of the coaxial line.

In this paper, modifications to the finite-difference time-domain(FD-TD) method for modeling microwave pulse coupling into a slot, which is much narrower than one conventional FD-TD cell, are discussed. The coupling process of microwave pulse into a slot is studied by using the modified FD-TD method, and the dependence of microwave coupling on slot sizes, the carrier frequencies and the polarization directions of the incident waves is analysed. Resonant and enhancement effects which occur in this process are observed. The condition at which the resonant effect takes place is also presented.

The FDTD collaborated with advancing algorithm in discretised time domain for plasma is applied to the analysis of scattering by a combinative object including PEC and plasma. More computation results indicate that the characteristics of combinative object in TE case are the same as in TM case. The cirtical frequency is mainly determined by plasma frqeuency. Further study of this phenomena will be our next work.

Passive intermodulation (PIM for short) problem in mobile communication is discussed. The PIM property of mobile communication antenna is analyzed by simplified power series method. PIM measurement on GMS mobile communication antenna is done to verify the nonlinear model. Comparison between experimental results and predicted one shows that the used theory is right and practical.

The formulations in finite-difference frequency-domain (FDFD) computational domain are obtained from Maxwell's equations. The absorbing boundary and total-field boundary are analyzed in detail in order to simulate electromagnetic scattering problems in open region. The incident wave is introduced by setting equivalent electromagnetic currents on the total-field boundary. In order to save memory and speed up the solving speed, a compressed storage scheme and the conjugate gradient method are adopted respectively. The Kirchhoff surface integral representation is used to calculate the far field from the FDFD near field data . Numerical examples are presented to verify this method.

The Time-Domain Physical-Optical (TD-PO) approximation is derived from the frequency-domain physical-optical expression by the inverse Fourier transformation. The transient scattering and RCS in a wide band of metal sphere and cube are computed. Numerical results show that TD-PO method requires relatively small amounts of computer memory and CPU time. It is an efficient algorithm for analyzing the wide band characteristic of electrically large objects.

The physical mechanism and analytical method of passive intermodulation in metallic contacts are studied. PIM interferences in metallic contacts mainly originate from contact nonlinearity. Several important nonlinear mechanisms such as electronics tunneling effects, multipactor discharge and contact mechanism are specially described. Power series analysis indicates that PIM power should vary as 3 dB/dB with the combined input power at equal amplitude two-carrier case. PIM power should vary log-linearly with the combined input power for carrier power ratio greater than 10 dB at unequal amplitude two-carrier and constant input power case; the strongest PIM for a given power is produced when the power at transmit carrier frequency closest to the IM frequency is about 3 dB higher than the other. Verification with related reference's measured data shows that the used theory is right and practical

Using shift operator method, the recursive relation for D/spl I.oarr/ and E/spl I.oarr/ available for FDTD computation of plasma coating is obtained. We apply FDTD and this relation to calculate wideband scattering for an airfoil with plasma coating. To verify the scheme we compute wideband RCS of a circular cylinder with plasma coating, which is in good agreement with the one in literature The computation of airfoil with plasma coating demonstrates the significant reduction of RCS in wideband from 2 - 20 GHz. Based on the results obtained we conjecture that larger electron density and higher electron collision frequency for plasma coating are preferable for the purpose of RCS reduction.

To analyze the radiation of a monopole covered with plasma, a shift operator method in FDTD is applied. By using this scheme we compute the radiation of a monopole antenna with the coverage of plasma. We observe from the numerical results that the plasma can greatly absorb electromagnetic waves and can impede the Gaussian pulse travelling along the antenna. In addition, the high frequency components in the radiation fields are decreased, and the resonant frequencies are shifted.

FDTD in combination with beam simulation is employed to compute the EM scattering from rough surfaces to enlarge the rough surfaces size that FDTD can deal with. The efficiency of this technique is demonstrated with numerical results.

This paper deals with an efficient three-dimensional finite-difference time-domain (FDTD) algorithm, which based on the D-, E-, and H-fields. This algorithm is proposed to handle arbitrary anisotropic dielectric media. By combining the FDTD approach with the material-independent perfectly matched-layer absorbers, the performance of a line-fed microstrip antenna patched on a general anisotropic dielectric substrate is developed. The scattering parameters of the antennas as a function of the rotation angle of the optical axis of the anisotropic substrate are presented. The results show how the resonant frequencies of the antenna are influenced by the anisotropy.

For the computation of electromagnetic scattering from a fractal rough surface, the authors consider the small perturbation method and a composite scattering model. A numerical simulation results are also given.

EM scattering from rough surfaces is calculated with FDTD when the incident wave is a planar and Gaussian beam. Its result is compared with the one obtained with the moment method. The case of a rough surface with an object superposed on it is also discussed.