臺灣博碩士論文加值系統

本篇論文採用一般化的傳輸線理論模型分析柱面微帶天線,本方法具有理
論簡易和數值分析計算時間短的優點.在同軸探針饋入的柱面圓形微帶天
線,微帶天線在其被激發方向可被視為一傳輸線加上在天線圓周上之磁牆
自導納為負載.而在推導傳輸線參數的部份,須定義模態電流與模態電壓以
推導出電路中之導納,利用此理論模式,可以推導出一等效電路 ,以及天線
輸入阻抗之表示式.其次,在槽孔耦合饋入的柱面圓形與矩形微帶天線,在
此引用等效變壓器觀念來解釋來電磁能量從微帶線經由槽孔耦合的結構,
此時整個等效電路是可以以傳輸線理論來解釋的.在此探討槽孔長度及圓
柱曲率對輸入阻抗之影響.最後探討在同軸探針饋入的兩個圓形微帶天線
之間的相互耦合,數值分析的結果顯示基板基底損耗對輸入阻抗及相互耦
合有很大的影響.數值分析的結果與實驗值作比較,證實此理論的準確性.

Analysis of microstrip antennas on cylindrical body using
generalized transmission line model (GTLM) theory is presented
in this dissertation. This method has the advantages of
simplicity and time efficiency on analysis of the microstrip
antenna. Base on the GTLM theory, a single probe-fed circular
microstrip antenna was first investigated. It can be
represented by a transmission line loaded with a wall
admittance at the radiating edge, an equivalent circuit for
calculating the input impedance of the microstrip antenna can
be obtained. The input impedance of different feed positions
were analyzed and discussed. The curvature effects are major
subjects of the presented study. Another feed method, the slot-
coupled circular and rectangular microstrip antennas were also
studied. By introducing equivalent transformers concept to
explain the coupling mechanism, it is easy to realized the
equivalent circuit by using transmission line theory. Finally,
the analysis of mutual coupling between two probe-fed circular
microstrip antennas both on a cylindrical and planar surface is
presented. Numerical results demonstrated that the substrate
loss tangent play a role on input impedance and the mutual
coupling coefficients. The curvature effects for typical
results on E- and H- plane coupling were presented.

COVER
TABLE OF CONTENTS
ABSTRACT
LIST OF FIGURES
CHAPTER 1 INTRODUCTION
1.1 Motivation
1.2 Literature Review
1.3 Organization of the Dissertation
CHAPTER 2 ANALYSIS OF A PROBE-FED CIRCULAR MICROSTRIP ANTENNA
2.1 Theoretical Formulation for Cylindrical Structure
2.1.1 Fields under the cylindrical-circular microstrip patch
2.1.2 Equivalent circuit representation
2.2 Theoretical Formulation for Planar Structure
2.3 Results and Discussion
CHAPTER 3 ANALYSIS OF A SLOT-COUPLED CYLINDRICAL-CIRCULAR MICROSTRIP ANTENNA
3.1 Theoretical Formulation for Cylindrical Structure
3.1.1 The transformer ratio
3.1.2 Patch admittance and slot admittance
3.1.3 Open-circuited tuning stub
3.2 Theroretical Formulation for Planar Structure
3.2.1 The transformer ratio
3.2.2 Patch admittance, slot admittance and open-circuited tuning stub
3.3 Results and Discussion
CHAPTER 4 ANALYSIS OF A SLOT-COUPLED CYLINDRICAL-RECTANGULAR MICROSTRIP ANTENNA
4.1 Theoretical Formulation
4.1.1 Equivalent circuit representation and input impedance
4.1.2 Patch admittance and slot admittance
4.2 Results and Discussion
CHAPTER 5 MUTUAL COUPLING BETWEEN TOW PROBE-FED CIRCULAR MICROSTRIP ANTENNAS
5.1 Mutual Coupling Problem and Two-Port Network
5.2 Mutual Admittance: Cylindrical-circular Microstrip Antennas
5.3 Mutual Admittance: Planar-circular Microstrip Antennas
5.4 Experimental Technique
5.5 Results and Discussion
CHAPTER 6 CONCLUSIONS
REFERENCES