A Compact Finite-Difference Frequency-Domain Method for Analysis of Microwave Transmission Lines with Rough Surface

Accurate modeling of microwave transmission lines is very important in microwave communication and radar systems, especially at high frequencies. A compact finite-difference frequencydomain method (FDFD) is presented to analyze the propagation characteristics of microwave transmission lines with rough conductor surface. Equations in the Maxwell system are discretized with difference method in the cross-section of the microwave transmission line, and rough surface of microwave transmission lines is replaced by complex surface impedance from the conductivity Gradient Model. The eigen equations of the electromagnetic field components are formed and solved to obtain the propagation constants for a given frequency. The presented method reduces the computer storage effectively in ensuring simulation accuracy without the direct modeling for surface roughness, which can be applied in the modeling of complex microwave circuits.