Extraction of higher-order modes in open microstrip lines via FDTD and joint time-frequency analysis

An analysis of the higher-order modes in open microstrip lines is presented based on the finite-difference--time-domain (FDTD) electromagnetic simulation in conjunction with the joint time-frequency processing of the resulting data. The wavelet transform is applied to the simulation data to distinguish the various higher-order modes in the joint time-frequency plane. Then, a technique that extracts the field information at a unique time-frequency point is used to construct the spatial field distribution of each mode. © 1996 John Wiley & Sons, Inc.