24GHz連續調頻雷達高靈敏度壓控振盪器之設計

Abstract

本論文提出一個應用在24 GH 車用連續調頻雷達系統收發機中的射頻前端電路： 12GHz 高靈敏度控振盪器，以20mils 厚的Rogers RO4003 板材、NEC 的NESG2030M04 SiGe NPN 電晶體以及Skyworks 的SMV1231 可變電容實現。

12GHz 高靈敏度壓控振盪器，以共射極(CE)作為基礎電路架構，並利用電晶體內 介於集極跟基極間的電容Ccb 提供回授以形成可產生豐富頻譜訊號的負電阻，最後再使用微帶線搭配可變電容設計可暫存負電阻激發功率且純化振盪頻率的諧振電路。其相位雜訊在100kHz 位移時為-90.33dBc/Hz，在1MHz 位移時為-105.67dBc/Hz，輸出功率最高為-0.67dBm，可調頻頻寬在Vctrl 從0 V 到3.3V 的狀況下可達到172.5MHz。換算靈敏度可達52.3MHz/V。

In this thesis, one RF front end circuit; a 12GHz novel VCO has proposed.It can be applied to 24GHz FMCW radar applications and which fabricates with Rogers RO4003 substrate, NEC NESG2030M04 SiGe NPN BJT and Skyworks SMV1231 varactor.

A common-Emitter construction has employed to the proposing 12GHz high sensitivity VCO. The Ccb which is between base and emitter of BJT is used to be a feedback path to let BJT plays as negative resistance so it generates wide band signal. Then resonator is designed by microstrip line and varactor. Resonator has two major functions; one is to store RF power which generates by negative resistance and the other one is to pure the resonating frequency. The phase noise is -90.33dBc/Hz at 100 kHz offset and -105.67dBc/Hz at 1 MHz offset. Maximum output power is -0.67dBm. And tuning range can reach to 172.5MHz with 0V to 3.3V control voltage. It’s equal to 52.3MHz/V.