Research Of Broadband Microwave Receiver Front-end

Broadband microwave receiver front-end is the key component of broadbandmicrowave communication system. Broadband microwave receiver front-end is widelyused in radar detection, UAV reconnaissance, satellite communication, electroniccountermeasure, tactical weapon guidance, microwave measurement, civilian radiocommunication and other fields. Multi-channel technology is generally used in thedesign of broadband microwave receiver front-end. First, bandwidth is divided intoseveral channels, and then down-conversion or up-conversion will be done. Interferencefrequency can be suppressed more easily using this method. Finally, a low IF signal canbe demodulated.At first, the overall program was designed according to the overall target. Theprogram was down-conversion after up-conversion. The target was divided into threeparts, which are a DC~6GHz low-pass filter, a2~6GHz broadband low noise amplifierand a broadband mixer. The indicators of the three microwave modules are determined.Negative feedback technology was adopted to design a2~6GHz broadband lownoise amplifier whose indicators were NF<2.5dB, G=25.15±1.75dB，S11<-7.502dB,S22<-7.561dB; A kind of ultra-wideband balun was used to design a mixer;HMC773LC3B was used to designed a mixer module whose indicators wereLc<10.33dB，LLO RF<30dB,LLO IF<30dB，LRF IF<8dB；Open stub structure wasadopted to design a DC~6GHz low-pass filter whose indicators were IL<0.5dB，RL>11dB and the rejection was greater than50dB from10.5GHz to20GHz；The systemindicators of the front-end were NF<2.5dB, DR=50.36dBc, SFDR=44.36dBc,S=-70.36dBm, IIP3>-8.1dBm.Firstly, the core characteristic of the thesis was the in-depth study on negativefeedback technology for engineering application. Negative feedback technology canmatch port impedance to50Ohm, can improve the gain at high frequency and cansignificantly improve stability. A large number of simulation was done using ADS. Alow noise amplifier had been developed which had low noise figure, flat gain, andsimple structure. Secondly, extensive debugging was done using HFSS. Eventually, a broadband balun with higher magnitude coherence and phase coherence had beendeveloped. Thirdly, a filter whose stop-band was up to20GHz had been designed.Finally, the system indicators had been detailed tested and given real photos.