可應用於三個緊鄰單極天線系統之解耦合電路設計：使用特徵模態分析

Abstract

近年來，人類對於無線通訊速度及品質的需求越來越高，多輸入多輸出之天線系統被視為是一個可以滿足需求之解決方案。但是在多天線彼此距離縮短時，增強的耦合會影響傳輸，如何壓抑耦合並維持天線匹配是一個必須解決的問題。 我們利用天線特徵模態具有正交且不會互相干擾之特性，於本篇論文中，為一對稱三埠天線系統量身訂造一可激發天線特徵模態之饋入網路。若此饋入網路可分別激發天線所擁有之特徵模態，可期待輸入間將不會互相干擾，耦合因而得以降低，我們針對一個三單極天線系統進行實作設計以驗證以上概念。

In recent years, there is a rise on the demand of speed and quality in wireless communication systems. MIMO antenna systems is considered as a possible candidate to improve the above demands. However, when the distance between multiple antenna is limited, the coupling between antenna elements will be severe and can deteriorate the matching of the antenna system. The coupling of MIMO antenna system is thus needed to be suppressed for practical applications. If one can excite the eigenmode of a multiple antenna system, one can expect the mode will not interfere with each other due to their orthogonal nature, This concept is used in this thesis, and a decoupling network for a three symmetric antenna system is proposed. By properly design the network to excite each individual mode of the antenna system, the interference between input is expected to be suppressed. This concept is experimentally verified on a three printed monopole antenna system.