臺灣博碩士論文加值系統

由於微帶天線具有成本低,重量輕且易於製造的優點,同時它可以鑲嵌在任
何曲面上的特性,近年來已被廣被應用於許多方面,如飛機,火箭和衛星通
訊上.以傳輸線理論的方法分析,它只能研究平面矩形的微帶天線,而對於
有曲率或不同形狀的微帶天線則無法分析,故本篇論文採用一般化的傳輸
線理論模式分析探針及微帶線饋入的柱面矩形微帶天線.在此論文中把傳
輸線理論一般化成可分析有曲率變化及適用於可分離變數之座標軸上的天
線,此時微帶天線此時可被視為在輻射方向之傳輸線,同時在其兩端加上磁
牆自導納及兩輻射端的互導納.而在推導傳輸線的部份,須定義模態電流及
模態電壓,以推出電路中之導納,而邊緣兩端之輻射可看成槽孔的等效磁流
在柱面上產生之電場及磁場.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.數值分析的結果顯示自導納及互導納對頻率的
影響,並求出輸入阻抗隨半徑增大而升高且厚度增加其頻寬亦隨之變大.而
傳輸線饋入之輸入阻抗以較大之半徑逼近平面的實驗值作比較,證實此理
論的準確性.

Due to their conformability the cylindrical-rectangular
microstrip antennas have received much antention. In this paper
we present a simple analysis method of using generalized
transmission line model (GTLM) theory. The excitation of the
patch antenna by a probe and microstripline is consider here,
and this study is still not available in the open literature.
To apply the GTLM theory, the microstrip antenna is model as a
sections of transmission lines taken in the direction that
joins the radiating edges and loaded with wall admittance at
the radiating edges. The mutual admittance between the
radiating edges is included in the GTLM solution. The
equivalent circuit that describes the GTLM analysis is given,
and the expressions for the circuit element are derived. The
input impedance of the microstrip antenna is then formulated.
Numerical results of the input impedance are calculated and
presented as a function of cylinder radius and substrate
thickness. To analyze the accuracy of the GTLM solutions, the
obtained results are also compared with the measured data.