利用串接左右手傳輸線架構之新微小平面式天線 : 設計與佈局

Abstract

本論文提出一個利用串接左右手傳輸線架構的新微小平面式天線。利用兩段電氣長度相同但是相位相反的傳輸線，也就是將一段右手傳輸線以及一段左手傳輸線串接後一端開路，另一端即能形成輸入阻抗虛部為零，並代入傳輸線的π型或T型等效電路。藉此一基本結構，透過適當的電路參數設計以及佈局，能夠得到得到一個微小的平面式天線。使用FR4基版實作的平面式天線，經過量測得到與模擬相同良好表現的驗證。在三個主要座標平面都得到頗為全向性的輻射場型。所提出以平板為主的佈局比傳統平板天線提供了更多數目的輻射邊端結構，而且只需要約十二分之一波長的尺寸。對於此串接左右手傳輸線架構，實作佈局的重要影響以及所提出微小平面式天線的輻射機制也做了分析討論。

A novel compact planar antenna utilizing cascaded right/left-handed transmission lines is proposed. The significance of layout planning with respect to radiation is investigated and discussed in this thesis. Two segments of transmission lines of equal electrical length with opposite sign are cascaded to provide zero phase at the operation frequency. The closed-form formulas for the equivalent circuit (EQC) of transmission line are used for circuit design. For experimental demonstration, the proposed antenna operating at GHz-range was implemented on an FR4 printed circuit board. Fairly omnidirectional radiation patterns were measured for all three principal planes. The patch-dominant topology shrinks the size of conventional patch antennas and provides more radiating edges.