Design And Application Of Microwave Interferometer

Microwave interferometer is widely used in national defense, aerospace, manufacturing, and other fields, for the design and application of microwave interferometer research is of great significance.This paper briefly introduces the principle of microwave interferometer, the structure of microwave interferometer with a single antenna is designed. The RF front-end hardware of microwave interferometer is accomplished, and realize the miniaturization of the system.Then a two-way signal acquisition system based on AD+ FPGA is also designed according to the requirements of the project, complete the system debugging.Secondly, based on the above microwave interferometer system, the application of the relative displacement measurement is studied. The measuring principle is analyzed, and the measuring formula is deduced. Focuses on the three key technologies for measurement process:phase unwrapping、circulator leakage error analysis and calibration, and the error analysis of the quadrature mixer. According to the experiment and data processing, the precision can reach 0.01 mm after the calibration.Again, a signature extraction from targets with micro-motions based on microwave interferometer is studied, and the application of rotating machinery fault detection are analyzed. This paper briefly introduces the concept of micro-motion and micro-Doppler feature, the model of rotating line-shaped target is set up, the approach is proposed for parameter estimation of rotating line-shaped target. After the experiment test, the error is less than 5%.Puts forward two kinds of detection methods for the fault detection, one is based on the signature extraction from rotating line-shaped target, the other is based on short-time Fourier transform (STFT), and the feasibility of the methods are verified by experiment. The advantages and disadvantages of two methods are compared.Finally, the thesis is summarized, and the further improvements are advised.