Abstract: 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.

Key words: nonorthogonal mesh, finite difference time domain, resonant frequency