Research Of Wide-band RF Receive Technology In The Coherent Radar Target Simulation System

Radar target simulator is the main component of the RF radar simulation system, which includeswide-band digital unit and wide-band RF unit. The research of RF receive system, which havingwide-band, high spurious suppression and high consistency in the band, is essential for ensuring thetechnical performance of the target simulator.Superheterodyne structure is used in the design of RF receive system. The features ofsuperheterodyne structure are having many frequency components and high spurious level. Thecontent of this paper is to design a RF receive system, which can move the spectrum of wide-band RFsignal, at the same time, with the advantages of high spurious rejection, large dynamic range, highfrequency-selective and high sensitivity-receive. The main work includes:Based on discussing various types of RF receive technology in detail, combined with theresearch of target simulator, RF receive system is designed by using superheterodyne structure.Frequency configuration is finished, which could improve the spurious rejection and channelselectivity to achieve a low spurious reception. The simulation of receive channel is finished by usingADS, which can confirm the good technical performance of RF receiving system designed in thepaper.Low noise amplifiers, band-pass filters, mixers, low-pass filter, amplifier and automatic gaincontrol circuit are analyzed and designed. The parasitic channel of filter is inhibited by increasing thetransmission zero. Many frequency components are reduced after mixing by using thedouble-balanced mixer. An amplifier is designed, with the adoption of the real frequency, lossymatching networks, and the feedforward linearization to realize the multi-octave bandwidth, goodevenness, and good third-order intermodulation suppression. Automatic gain control circuit, based onFPGA, can control the gain of narrow pulse signal, with the advantages of short response time, highregulation accuracy.Wide-band devices are made for testing, test results are given and analyzed and solution is givenfor the problems found in testing. RF receive system is tested, according to the tested result, the RFreceive system meet the technical requirements of the target simulator.