雷達(Radar)為無線電探測與測距的簡稱，雷達誕生於二戰，目的為辨別敵方與友方的部隊，在防禦與進攻中發揮了至關重要的作用，故雷達前期只用於軍方。隨著戰爭的結束雷達技術也逐漸廣用在民間，不論是汽車雷達、飛機雷達、天氣預報與民生醫療上，雷達的精確、準確度與敏感度都得大幅的提升與改善，因此大家對於雷達的需求逐漸提升。

在一個應用於接收端雷達系統中，天線接收到傳輸端(TX)射頻訊號時，前端電路會將訊號直接取樣或降頻接收，並經過低雜訊放大器(LNA)放大至可供後放電路辨識處理的大小後，交給後方基頻電路做一些訊號放大與低通濾波，並經過電壓緩衝器隔絕電路後交給後方類比數位轉換器，取得使用者所想要的數位訊號。總而言之，類比基頻電路主要是應用於雷達後端的系統，目的為訊號放大以及高頻雜訊濾除的部分。

本論文提出了一個類比基頻電路設計，其中包含了四級可變式增益放大器，放大倍數為0dB(1倍)～80dB(10000倍)，後方為多重回授低通濾波器或Tow-Thomas Biquad低通濾波器所組成，截止頻率為50M赫茲，可供讀者依據功率、面積以及電路對元件的敏感度做選擇，此外通帶內有良好的響應，並依據電路決定濾波器階數，後方由等化器所組成，其目的為補償低通濾波群延遲所造成的失真，最後面由電壓緩衝器所組成，隔絕了與類比數位轉換器的影響。本論文是使用台積電65奈米CMOS製程設計，供應電壓為1.2伏。

Radar is the abbreviation of radio detection and ranging. The radar was created in World War II. The purpose of distinguishing between enemy and friendly forces is to play an important role in defense and offense. Therefore, the radar was only used in the military before. With the end of the war, radar technology has also been widely used in our society. Whether it is automobile radar, aircraft radar, weather forecast and people's livelihood medical care, accuracy and sensitivity of the radar have been greatly improved . The demand for radar is gradually increasing.

In a radar system applied to the receiving end, when the antenna receives the RF signal of the transmitting end (TX), the front-end circuit directly samples or down-converts the signal, and is amplified by a low noise amplifier (LNA) to be available for the baseband circuit. The signal is sent to the rear baseband circuit for signal amplification and low-pass filtering, and then passed through the voltage buffer to isolate circuit and then passed to the analog digital converter to obtain the digital signal desired. In summary, the analog baseband circuit is mainly applied to the back-end of radar system for the purpose of signal amplification and high-frequency noise filtering.

This paper proposes an analog baseband circuit design, which includes a four-stage variable gain amplifier with a magnification of 0dB (1x) to 80dB (10000x), followed by a multiple-feedback low-pass filter or Tow-Thomas The Biquad low-pass filter with a cut-off frequency of 50M Hz. It allows the reader to choose the power, area and sensitivity of the circuit to the component. In addition, there is a good response in the pass-band and the order of filter is determined by the circuit. The latter is composed of Equalizer, the purpose of which is to compensate for the distortion caused by the low-pass filter group delay, and finally consists of a voltage buffer, which isolates the influence of the analog-to-digital converter. This paper is designed using TSMC 65nm CMOS process with a supply voltage of 1.2V.

中文摘要
Abstract
第一章 簡介-------------------------1
第二章 研究背景及相關研究-------------3
第三章 應用於雷達後端之類比基頻電路----19
第四章 結論與電路改善-----------------131
附錄---------------------------------133
參考文獻-----------------------------145

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