利用反相位饋入串接微帶陣列之多層羅曼透鏡天線應用於77GHz車用防撞警示雷達系統

Abstract

本論文中設計一個應用於77 GHz車用前視防撞雷達之雙模態天線系統，操作頻段為76∼81GHz，主要架構由羅曼透鏡天線(Rotman Lens Antenna)、反相位饋入串接微帶天線陣列以及不同應用之分功器組合而成。利用羅曼透鏡天線與反相位饋入串接微帶天線列達到高增益、多波束且特定偏移角度之特性，此設計使用於遠距離模態之接收端天線。此設計之優點是利用多層電路架構使得整體天線系統所需面積大量縮減。反相位饋入微帶天線陣列與不同的分功器分別組合成遠距離模態發射端天線與近距離模態天線，達成高增益且寬波束的特性。其中近距離模態天線可搭配DBF(Digital Beamforming)演算法來進行物體之角度偵測。另外，整體天線系統之走線布局必須在有限面積下盡量將接收與發射天線之間距離拉遠，以提升系統的隔離度。

In this thesis, a dual-mode antenna system applied to 77-GHz vehicle collision warning radar system has been designed, and the operating frequency is 76GHz to 81GHz. The main structure contains Rotman Lens antenna, the anti-phase feed series patch array and the different type power dividers. In order to get high gain, multi-beam and specific beam-tilt angle, Rotman lens antenna fed with an anti-phase feed series patch array was proposed as receiving antenna of long-range mode. The advantage of this design is used multilayer technique which reduced the whole size of the antenna system. Anti-phase feed series patch array combined with different type power divider could compose antennas for long-range mode and short-range mode to achieve high gain and wide-beam. The antennas of short-range mode could cooperate with Digital Beam Forming (DBF) algorithm to detect the relative angle of targets. In addition, the layout of whole antenna system must enlarge the distance between transmitting and receiving antennas to increase system isolation.