漸變開槽饋入式超寬頻天線之設計與分析

Abstract

本論文提出一系列利用漸變開槽饋入結構設計實現之新型超寬頻平面天線。論文中針對『漸變開槽饋入式印刷偶極天線』、『漸變開槽饋入式環狀開槽天線』、以及『具帶拒特性之漸變開槽饋入式天線』等三種新型結構進行探討。本論文首先針對分析超寬頻天線所需要之必要技術作一討論。這些技術包含量測『系統轉移函數』及新提出之『無因次正規化天線轉移函數』的實驗技術、獲取時域暫態波形的技術、以及評估超寬頻天線性能之定量化尺度，場型均勻度及信號保真度的求取技術。為了簡化『無因次正規化天線轉移函數』的求取，本論文亦針對傳統雙天線增益量測法進行了改良。應用上述分析技巧及傳統天線參數包含返回損失、場型、及增益，此新型天線在頻域及時域上的特性獲得了完整的分析。論文中詳細介紹了漸變開槽餽入式天線的實驗結果、設計原理及相關討論，亦驗證此天線在目前廣為看好之超寬頻系統中的適用性。

In this dissertation a new category of ultra-wideband (UWB) planar antennas with a unique tapered-slot feeding structure is presented. Three novel antennas are proposed and discussed, which include a tapered-slot-fed printed dipole antenna, a tapered-slot-fed annular slot antenna, and a tapered-slot-fed antenna with band-notched characteristics. The essential techniques for analyzing an ultra-wideband antenna are introduced, which include the techniques for measuring the system transfer function and the newly proposed dimensionless normalized antenna transfer function, the technique for achieving the transient waveforms, and the techniques for evaluating the quantitative measures, the uniformity and fidelity, to describe the performance of an UWB antenna. To simplify the evaluation of the dimensionless normalized antenna transfer function, the conventional two-antenna gain measurement method is also improved. The antenna characterizations in both frequency and time domains are investigated thoroughly with these techniques as well as with the traditional antenna parameters including return losses, radiation patterns, and gains. The experimental results, design principles, and discussions are presented in detail. The applicability of the proposed tapered-slot-fed antennas to the promising UWB applications is substantiated.