Development Of The Microwave Sensor System

We have developed a microwave sensor system based on the Coaxial CableBragg Grating(CCBG) mainly for the structure strain sensing application. Thefundamental work of this paper is the research on the sensing characteristics of theCCBG, based on which we analyzed the signal requirement and developed thesupporting demodulator.Based on the sensing characteristics of the CCBG, we designed the demodulatorstructure strain sensing application. We designed the frequency sweep source,microwave signal amplifier and microwave detector and the digital controller module.According to our analysis, the sweep source should have a low noise and small stepsize and the microwave signal amplifier should have enough gain to satisfy the powerrequirement of the CCBG.In view of the fact that this work mainly focuses on microwave design, weconsider it necessary that some concepts related to it should be clarified first. Becausethey are the key factors that influence the final performance of the RF functioncomponents and thus determine whether our design is successful.The most important part of this work is microwave design including frequencysweep source, microwave signal amplifier and microwave detector. We gaveabundant space in this paper to present the development process and the results havebeen illustrated. According to our test, the frequency sweep source can output3dBmsignal at most and has a3Hz step size using24bit control words. The microwaveamplifier consists of a low noise amplifying part and a subsequent power amplifyingpart, which guarantees both a low noise performance and high out power. The testshows result shows that it has a20dB gain and a2dB flatness with the capability ofoutputting signal up to20dBm.At last, we present the test results and make a summary of the existing work andhave a outlook on the future improvement.