Study And Design Of The RF Front-end For Wideband Radar Signal Simulator

Wideband radar signal simulators are commonly used in electroniccountermeasures technology, new electronic warfare equipment development and thetraining of electronic warfare troops. It is the equipment that can provide broadband,intensive and complex electromagnetic environment, and also can provide thecharacteristics of the radar signal. The front-end of wideband radar signal simulator RFincludes two parts. One is microwave up-converter unit which in the broadband radarsignal simulator system. The other is local frequency synthesizer unit. With a IF signalgenerator, microwave power amplifiers, transmitting antennas, monitoring computerand software, AC-DC power converters, the RF front-end can constitute a simulationsystem to generate broadband, intensive, complex radar signal or communication signal.The front-end of wideband radar signal simulator RF includes two keytechnologies： the broadband microwave up-converter and broadband frequencysynthesizer with fast frequency hopping. In this paper, these two techniques will be themain object of this study. Based on in-depth analysis of the theory and technology, thesystem architecture and the spurious generation of this broadband up-converter and fasthopping frequency synthesizer are discussed in detail. The main achievements of thiswork are summarized as follows：1. The broadband microwave up-converter technology is studied, and a method ofbroadband microwave frequency converter is proposed. Its functions, performanceindicators and development program are introduced. There will be two IF input ports.The center frequency and instantaneous bandwidth of this two IF signal are as follows:80MHz,20MHz;300MHz,200MHz. These two ports can input simultaneously. Afterpassing through up-converter, the microwave signal with center frequency’s coveragearea from1GHz to18GHz is exported, and the clutter suppression is greater than50dBc.So that both the narrow and the wide instantaneous frequency bandwidth of the signalcan be simulated, also the signal reached simultaneously can be simulated.2.By studying the advantages and disadvantages of various frequency synthesizertechnology, a fast frequency-hopping frequency synthesized local oscillator signal source for broadband microwave up-converter is designed. Its frequency hopping timeis less than3micro-seconds, the frequency step is10kHz, and the typical phase noise isbetter than90dBc/Hz@10kHz.3.Through the study, analysis and use of EMC technology, the EMC design formicrowave modules and chassis is carried out. And this makes broadband radar signalsimulators (including RF front-end, IF signal generators, microwave power amplifier,monitoring computer and software, AC-DC power converters, etc.) can be integratedinto a3U standard chassis with19inches wide and480mm depth.