Algorithm Studies And Application Of Time Domain Integral Equation On The Problem Of Wire Antenna

The objective of studying electromagnetic theory and developing modern computing algorithm is to solve all kinds of engineering electromagnetic problems. The modeling and simulation of thin-wire structure and surface structure are applied widely in the areas of antenna design, radar target identification and EMC analysis. Time domain integral equation (TDIE) provides an unique advantage for solving broadband and transient electromagnetic problems. The purpose of this thesis is to investigate a marching- on-in-time (MOT) algorithm of TDIE for an application to antenna problems.In this thesis, the time-harmonic electromagnetic theory is presented. The time domain integral equation, which is comprised of TDEFIE, TDMFIE and TDCFIE, is established to solve electromagnetic problems from arbitrarily shaped conducting objects. The numerical performance and applied range of TDEFIE, TDMFIE and TDCFIE are discussed respectively. The MOT algorithm for solving thin-wire problems is developed, and the selection of spatial basis function and temporal basis function are discussed meanwhile. The difference of numerical precision between the resistance matrix with integral form and matrix with differential form is discussed for choosing a suitable resistance matrix. An improved half-numerical and half-analytical method is proposed for the accurate computation of resistance matrix elements with the form of differential TDEFIE. The computational precision is improved with the reform of both the integral at inner layer and outer layer. The exact modeling and simulation for wire junction, wire ring with quadrate shaped, dipole antenna, yagi antenna and log-period antenna are presented as the examples. The modeling and simulation of a surface-wire junction is considered based on the above discussion of the structure of wire, and the resistance matrix of the surface-wire junction is established for computing complicated target.