FINITE-DIFFERENCE TIME-DOMAIN ANALYSIS OF PLANAR STRUCTURES

Abstract

The Finite difference time domain method (FD-TD) is the main topic of this thesis. The project considers the work of improving the method itself and the application of the method to solve planar circuit problems. The absorbing boundary condition(ABC), which is a key aspect of the FD-TD method, is first discussed in the thesis. The Liao's ABC is studied in detail and compared with the conventional G.Mur's ABC. Results show the Liao's ABC is an efficient and accurate ABC. Suggestions for using Liao's ABC in waveguide case are also given. During the course of the project execution, a number of issues of importance such as the description of the incident field, the placement of the symmetrical boundary and the method of extraction of S-parameters are investigated. xii For application of the FD-TD method, a 3-dimensional computer program for analysing planar circuit in open environment is developed. The coplanar waveguide and slotline with discontinuity are intensively studied. Frequency-dependent results are provided which are useful for computer aided design applications.