Time-domain Characterization of Diode Mounting Structures

The application of the FDTD technique in the calculation of the S-parameters of specific diode mounting and waveguide probe structures is discussed in this paper. Comparative results are given and the FDTD technique is evaluated as an optimized CAD tool. Introduction The finite difference time domain method is used in the RF characterization of diode mounting and waveguide probe structures. A variety of excitation functions are considered and their effect on numerical convergence is studied. One of these functions, the Gabor function, offers a wavelet-like behavior. This function is localized both in time and frequency domain and its characteristics can be chosen such that its spectral content is centered around a desired frequency. As a first step, a number of simple geometries are analyzed and the FDTD results are compared to data derived through the integral equation and finite element methods for validation purposes. The same technique has been applied to waveguide-probe structures and the S-parameters as a function of frequency have been evaluated. Theory The FDTD method is formulated by discretizing Maxwell's curl equations