可激發單導體洩漏波天線奇偶模饋入架構暨基於電容性凹槽耦合非對稱共平面波導共振子四埠波束切換天線

Abstract

本篇論文包含兩個部分，第一部分是可激發單導體洩漏波天線奇偶模饋入架構，第二部分為基於電容性凹槽偶和非對稱共平面波導共振子四埠波束切換天線。 第一部份的天線為基於單導體洩漏波天線之設計，由於單導體洩漏波天線的基本特性為完美電牆/磁牆位於單導體中心對稱，這兩種情況我們給他稱為奇偶模。藉由設計出寬頻饋入式架構可以達成同時激發這兩種模態的目的。在奇模時，場型幾乎為水平方向(end fire)，而在偶模時，此洩漏波天線可表現出長線天線(long wire antenna)特性。 第二部分的天線為基於電榮幸凹槽偶和非對稱共平面波導共振子四埠波束切換天線，在非對稱共平面波導的架構中，將此共平面波導的共地結構縮小，這結構改變了共平面波導的電流特性，增強了此結構的輻射特性，知可用於天線設計，其中我們使用了帶通濾波器的設計原理來決定此天線的共振頻帶;如給此天線饋入不同的訊號相位，天線也會產生不同的輻射場型，而由於非對稱特性容易受到平面波導傳輸線或是微帶傳輸線的影響，所以藉由帶狀式四埠饋入結構來激發此天線既可以不影響此天線場型也可從不同埠中輸入訊號來切換波束。

This thesis consist of two parts: dual mode of feeding structure for single conductor strip leaky wave antenna and four ports beam switching antenna using capacitive gap coupled ACPW resonator. In the first part, the dual mode of feeding structure for single conductor strip leaky wave antenna is proposed. There is a PEC/PMC wall assumed at the center of the single conductor strip. Firstly, in order to excite dual mode of single conductor leaky wave antenna, the broadband feeding structure which can generate out-of-phase and in-phase signal is designed. In second step, we combine the broadband feeding network and the single conductor strip leaky wave antenna, the antenna will have different radiation characteristic. One mode make main beam toward end fire direction, the other mode can make the radiation behave as long wire antenna. In our second design, the four ports beam switching antenna using capacitive gap coupled ACPW resonator is proposed. The asymmetric ground of ACPW alters the ground current in purpose, which enhances the radiation from the structure. This characteristic can be well suited in antenna applications. We use the theory of band-pass filter to make this antenna. This antenna will generate different radiation pattern by different feeding signals. The antenna of ACPW structure is easily affected by CPW or micro-strip transmission line. Thus, four ports feeding network of strip-line form that can generate four kinds feeding signal to antenna is presented. The four ports feeding network of strip-line form that can generate four kinds feeding signal to antenna is presented. When the feeding network combine with the antenna using ACPW resonator coupled capacitive gap, we can obtain the beam switching antenna by feeding different port.