應用於24GHz汽車盲點警示雷達之雙模射頻電路設計

Abstract

本論文提出一個具雙模操作之24GHz雷達之射頻模組，應用於盲點警示系統，包含倍頻器、12GHz放大器、24GHz低雜訊放大器、混頻器。使用現在市場上常用的高頻電晶體，它具有價錢低、低雜訊、可操作於於高頻之之優點，模擬電晶體的輸出功率逼近量測的結果，進而重建此電晶體之非線性模型，利用建立好的電晶體模型進而完成了倍頻器及放大器的設計。另外，使用低成本的二極體元件製作次諧波混頻器，本地振盪訊號頻率只需24GHz射頻訊號的一半即可推動，減少製作24GHz訊號源上的成本。因此我們系統的射頻電路有成本較低之優點。雙模雷達架構採用兩個發射路徑及一個接收路徑，利用開關電路分別切換發射路徑上的12GHz至24GHz倍頻器之偏壓電壓，此兩路徑間接發射訊號，設計兩支發射天線輻射出去的方向，使偵測範圍可涵蓋車子後面及側邊之盲點區，達到雙模操作的目的。最後射頻電路與天線整合，量測雷達系統之可行性。

In this thesis, a 24GHz radar RF module with dual-mode operation is presented and it’s application to blind spot warning system, This module consists of doublers, 12GHz amplifiers, 24GHz low noise amplifiers, mixers. This module uses the high-frequency transistors commonly used on the market nowadays, it has advantages such as low price, low noise, operating of high-frequency, simulated output power of transistors are in good agreement with the measurement results, hence we can rebuild the nonlinear model of transistor, and using this well-established transistor model to complete the design of doubler and amplifier. In addition, to fabricate harmonic mixer using low cost diode components, a local signal frequency promote the mixer using only half of the 24GHz RF signals, reduced the cost of producing 24GHz signal source. Therefore, our RF circuits system have the advantages of lower cost. Dual mode radar architecture uses two transmit paths and a receive path. Hence this module utilizes a switch circuit to switch the bias voltage of two 12GHz to 24GHz frequency doublers in the transmit paths, two paths transmit signal indirectly, design the radiation direction of transmitting antennas. To make the back and sides of a car's blind spot in the detection range, to achieve the purpose of dual-mode operation. Finally, we present the integration of RF circuits and antennas, and measure the feasibility of the radar system.