本論文主要探討在多層介質中天線的輻射特性，共分成兩章。第一章分析偶極天線陣列圍繞在金屬圓柱外的輻射特性。先採用差分方程式法求解格林函數，再以矩量法求解天線上的電流分佈。場型則使用解析法及穩態相位法求得。其中探討金屬圓柱半徑、天線擺放位置、天線與金屬圓柱之距離、天線數目等參數對輻射場型的影響。分析結果顯示可採用此種架構做為適應性天線陣列。
第二章分析片狀天線在有限基板上的輻射特性。先推導在多層介質中的場分佈，並定義反射係數以簡化推導過程。其中採用兩種方式來推導積分方程式，再使用矩量法計算天線上的電流分佈。The goal of this thesis is to investigate the radiation properties of antennas embedded in a layered medium. This thesis consists of two chapters. In the first chapter, we analyze the radiation properties of a dipole array mounted on a metal post. First, using a finite difference scheme to obtain the Green's function based on which an integral equation is formed. Method of moments is then applied to solve the integral equation for the current distributions on the dipoles. The radiation field is then derived by using analytic approach and stationary phase approximation. The effects of metal post radius, dipole positions, distance between dipoles and metal post, and dipole number are studied. Simulation results show that such an array can be used as an adaptive array.
In second chapter, we calculate the radiation characteristics of patch antennas with finite ground plane embedded in a layered medium. We first derive the field expression in the layered medium where reflection coefficients are defined to facilitate the derivations. Two approached are used to derive the integral equations, method of moments is then applied to solve for current distributions.Abstract (in Chinese).......................................3
Abstract (in English).......................................4
Acknowledgment..............................................5
Table of Contents...........................................6
List of Figures.............................................8
1. RADIATION PROPERTIES OF A DIPOLE ARRAY MOUNTED ON A
METAL POST..................................................13
1.1 Abstract................................................13
1.2 Introduction............................................14
1.3 Integral Equation for Current Distribution..............15
1.4 Radiation Field.........................................22
1.5 Results and Discussions.................................29
1.6 Conclusions.............................................33
1.7 Appendix................................................34
2. PATCH ANTENNAS WITH FINITE GROUND PLANE IN A LAYERED
MEDIUM......................................................64
2.1 Abstract................................................64
2.2 Introduction............................................64
2.3 Integral Equation for Current Distribution..............66
2.4 Integral Equation br Superposition......................77
Bibliography................................................89
Biographical Note...........................................9
