ESTIMATION OF HIGHER-ORDER MODES USING PRONYS METHOD IN THE FINITE DIFFERENCE-TIME DIFFERENCE METHOD

One of the characteristics of the finite difference-time difference (F D-TD) method, which is a three-dimensional time domain analysis techni que for the electromagnetic field, is its ability to obtain broadband frequency characteristics by one calculation if the pulse response wav eform is Fourier transformed. However, in the system where higher-orde r modes may be generated, it is not possible to obtain the frequency c haracteristics with this procedure. A new method to cope with this pro blem is proposed here. This method consists of the conventional Fourie r transform and Prony's method used in signal processing. The proposed method can be applied to a system containing an arbitrary number of m odes. In this paper, as an example, the method is applied to a wavegui de discontinuity problem so that the validity and effectiveness of the method are confirmed.