針對雷達系統應用之洩漏波天線研究與設計

本論文研究並提出一系統設計方法以應用於雷達系統之洩漏波天線設計。於傳統周期性洩漏波天線設計中，中心頻帶常存在禁帶而使天線無法往正上方輻射。本文透過對結構單位元的特徵態分析，得以簡化傳統理論並提出一個可系統化壓抑其禁帶的設計流程。此方法得以讓洩漏波天線可以在進行頻率掃描時，不會因為經過禁帶而喪失輻射能力。以上述理論為基礎，本文討論兩個設計案例。首先，我們探討傳統串聯饋入微帶天線陣列之設計，進而完成一個具有-47.8。至+17.1。角度掃描範圍的洩漏波天線；接下來，本文提出一可達廣角掃描的新型微帶法蘭克林周期性洩漏波天線設計。透過使用-2階空間諧波，此天線得以在低介電係數之印刷電路板上實現並具有-54。至+55。的掃描範圍。因此該天線可進行廣角掃描，結構簡單並容易和電路整合，於毫米波雷達應用中有著很大的應用潛力。最後，本論文利用洩漏波天線波束可作頻率掃描之特性，與電路整合而完成一可偵測方位角的毫米波都普勒雷達。此雷達可分辨-30。至+15。方位角範圍中，不同方位角的震動物體。

關鍵字

洩漏波天線；周期性；特徵態；富蘭克林

並列摘要

In this dissertation, an extensive study on the application of leaky-wave antennas for radar applications is given. Open-stopband effects are common phenomenons in periodic leaky-wave antennas which limit the scanning performance of the antenna. To make the antenna capable of radiating towards broadside direction, a novel eigenstate analysis-based design flow is developed in this study, which leads to a simpler, structure-independent and intuitive approach for the implementation of reflection-cancellation concept to eliminate open-stopband effects. With the theory developed above, two design examples are studied in this dissertation. Firstly, a classic series-fed microstrip patch antenna array is designed as a leaky-wave antenna with a -47.8。 to +17.1。 scanning range. Secondly, a novel periodic leaky-wave antenna using modified microstrip Franklin unit cells is proposed. Two additional quarter-wave asymmetric couple-line sections are used to allow the cell to work with the n = -2 fast-wave harmonic. It allows the use of low-εr substrates so the designed LWA is cost-effective, can be easily integrated with radar front-end circuits, avoids the excitation of surface waves and the beam can scan continuously from -54。 to +55。. Finally, a leaky-wave antenna integrated-millimeter-wave Doppler radar is discussed. The designed radar is capable of distinguishing different vibrating obstacles in the angular range -30。 to +15。.