用於汽車防撞雷達之洩漏波天線陣列

Abstract

在本論文中，我們提出兩種可應用於24ＧＨｚ汽車防撞雷達(Automotive Collision-Avoidance Radar)之前端天線，並對汽車防撞雷達系統的基本需求予以說明。本論文所提出的天線皆為微帶洩漏波天線，具有結構簡單、低成本，且高增益、高輻射效率等優點。 本論文所提出的天線結構，其基本形式皆為微帶洩漏波天線，利用槽孔耦合方式激發第一高階模，以多段微帶線輻射及波合成的方式來達成符合汽車防撞雷達前端天線的場型需求，此外，並利用波導模型予以計算天線輻射場型。 第一種類型之天線，是由微帶線中央饋入，產生雙波束場型，並與1×8洩漏波陣列組成三個波瓣，並利用微帶線的差異，可得到兩種涵蓋範圍不同的天線﹔第二種類型，是利用多段微帶線輻射的方式，以達成兩個固定角度且寬波瓣的波束，其兩波束的夾角且約為90∘，增益為13.2 dBi。

In this thesis, we propose two kinds of antenna array to apply to automotive collision-avoidance radar at 24 GHz, and provide the illustration of the basic system requirements for automotive collision-avoidance radar. The foundations of all proposed antennas in this thesis are microstrip leaky-wave antennas with low profile, low cost, high directivity, and high radiation efficiency. The structure of all proposed antennas in this thesis are microstrip leaky-wave antenna with aperture-coupled feed, operating in first higher order mode. We can obtain the radiation patterns conformed with the system requirements for automotive collision-avoidance radar by use of wave-composed and multi-section radiation. Besides, the waveguide model is used to calculate the radiation pattern. The first kind of antennas are fed from the center of microstrip line produce dual-beam, composing with 1×8 leaky-wave array, and we can obtain three beam pattern. Besides, we can change the structure of microstrip line to obtain antennas with different radiation pattern﹔The second is dual-beam with fixed beam and broad-beamwidth by use of multi-section microstrip line, whose included angle between the dual-beam is about 90°, and peak-gain is about 13.2 dBi at 24 GHz.