具地面多路徑反射補償效應之嶄新24GHz車用雷達設計

Abstract

本論文提出一24GHz汽車防撞雷達架構，此架構具有補償地面多路徑反射的效應，消除遠距離目標物訊號不穩定的情況。地面多路徑反射會使遠距離偵測物回波訊號不穩定，本論文基於此現象建立模擬環境，考慮地面多路徑反射、汽車雷達截面積、地面反射係數等參數，計算出回波訊號的大小，觀察各參數對於回波訊號大小的影響，得出結論，在垂直地面方向，兩個接收端相差五公分就能有效補償地面多路徑反射效應。本論文中提出一垂直極化低旁波瓣長距微帶天線陣列應用於此雷達架構中，天線操作頻段符合24 至24.2 GHz，雷達為雙層基板，天線層與電路層分開以縮小整體尺寸，雷達整體尺寸為 68mm* 107mm* 0.76mm。

In this thesis, A novel 24GHz vehicle collision avoidance warning radar architecture is proposed that has compensate the effect of ground-multipath reflections. This design can eliminate unstable signal when detecting long range targets. The effect of ground-multipath reflections will cause the received power to be unstable. To address this problem, this thesis establishes a simulation environment, considering ground-multipath reflections, radar cross section and road reflection. It is concluded by observing the received power when tuning the parameter. In the direction perpendicular to the ground, two received channels which is separated by 5 cm can compensate the effect of ground-multipath reflections effectively. This paper alse presents a microstrip antenna array for long-distance radar architectures.The presented antenna has some excellent characteristics such as low sidelobe level and vertical polarization. The operation frequency range is from 24 GHz to 24.2 GHz. In this radar structure, there are two substrates which are separated to reduce the overall size. The radar overall size is 68 mm*107 mm*0.76 mm.