A novel finite-difference time-domain(FDTD) method combined with semi-analytical recursive convolution (SARC) algorithm in digital signal processing(DSP) techniques is presented to analyze electromagnetic scattering by dispersive media.Absolute stability,high accuracy,less storage and high effectiveness are retained while a unified update formulation is possessed.It can be applied to analysis of general dispersive media provided that the poles and corresponding coefficients in dispersive medium are given.Finally,the proposed SARC-FDTD approach is validated.RCS of an object coated with plasma are calculated.

A total-field/scattered-field (TF/SF) technique is used to introduce an incident wave for a scattering problem in three-dimensional finite-difference frequency-domain (FDFD) method. According to the equivalence principle, an incident wave is introduced in total-field region by setting equivalent electromagnetic currents on TF/SF boundary. FDFD equations at nodes near TF/SF boundary are modified to satisfy conditions that all nodes involved belong either to total-field or to scattered-field. Numerical results validate this technique. The presented technique is mainly applied to scattering problem with a composite target,which is composed of perfectly electronic conductor (PEC) and lossy dielectric medium. Bistatic radar cross section (RCS) of a composite yon Karman missile warhead and a missile model are computed with FDFD method. The results demonstrate its applicability in analyzing electromagnetic scattering with composite targets.

A nonorthogonal finite difference time domain algorithm is used to model the excitation and resonance processes of a circular resonator with an excitation aperture,where a Gaussian pulse and a sine modulated Gaussian pulse are used as excitation pulses.Resonant frequencies are analysed by the method of fast Fourier transform.The calculated results agree well with theoretical analyses.Simulation results show that several resonant frequencies nearest to the main ferquency of the excitation pulse are excited.

FDTD is a numerical method to seek the solution of Maxwell equations by marching in tihme domain, which can be used to analyze the interactions between electromagnetic fields and complicated objects. The fundamentals of FDTD are discussed in this paper, and some useful skills introduced. In particular, complex field components are used in time-harmonic case in order to obtain smooth output for phase. Finally, some examples are provided.