24-GHz連續調頻單脈衝技術之雷達前端電路設計與整合

Abstract

本論文中設計一個24 GHz雷達射頻模組。此射頻模組包含6GHz電壓控制震盪器、12GHz功率放大器、倍頻器、24GHz帶通濾波器、枝幹耦合器、次階混頻器與24GHz低雜訊放大器。同時，利用金屬槽孔耦合技術，使得天線在不增加額外面積的情況下，僅付出插入損失0.8dB。此雷達除了利用連續調頻的技術得知物體的相對距離，並加入單脈衝的技術來判斷物體的角度。 最後為了驗證此連續調頻單脈衝射頻模組實際上運用的效果，搭配天線系統與數位訊號處理模組，射頻模組與天線系統總體積為9.4 × 9.4 × 1.7cm3，並從已知場型來校正Σ與Δ接收路徑的不平衡。最後實際測量金屬圓柱與小型轎車等目標物在不同距離與不同角度之Σ與Δ的比值，以及Σ與Δ混頻頻率。從量測結果得出此雷達的偵測能力可以達到30公尺內正負25度的範圍。

A 24 GHz RF-module has been developed in this thesis. This RF-module consists of 6 GHz voltage control oscillator (VCO), frequency doubler, 12 GHz power amplifier, 24 GHz band-pass filter, 24 GHz branch-line, sub-harmonic mixer and 24 GHz low noise amplifier (LNA). Moreover, we make use of cavity couplers so that Tx as well as Rx antennas do not increase extra area, and the insertion loss is only 0.8dB as a cost. This radar not only use FMCW technique to obtain the object’s distance but also add Monopulse to determine the object’s direction. In order to verify this FMCW Monopulse RF module, we combine it with antenna system and DSP-module as a radar system, and the RF transceiver’s volume is 9.4 × 9.4 × 1.7 cm3. After making an adjustment to cancel the Σ and Δ ports imbalance, we measure the Σ to Δ ratio of a metal cylinder and a car at different angles and distances, and also measure the mixed frequency of Σ as well as Δ signals. Finally, this radar’s detection ability can be achieved to 30 meters within ±25°.