Detection System Based On Microwave Power Sensor

For decades, microwave technology has developed into a relatively systematic subject, which has been widely used in many areas, such as communication, radar, electronic information warfare, electronic navigation and so on. Microwave technology is now affecting all aspects of our production and life. Microwave power is one of the important parameters characterizing microwave signals, which is indispensable in the process of transmission and reception. Microwave power sensor is the most common microwave measuring instrument. The function of microwave detection system is to amplify and filter the weak signal of the microwave power sensor, and then display it in the instrument through the analog digital conversion, if there is no reasonable microwave power detection system, the application of microwave power sensor will be greatly restricted.The thermoelectric MEMS microwave power sensor based on the MEMS technology and compatible with MMIC GaAs technology has been analyzed in this paper. Then, the sensitivity and signal to noise ratio of the microwave power sensor are studied, simulated and tested. Choice of high sensitivity, low signal to noise ratio of the microwave power sensor can reduce the signal to noise ratio of the microwave power detection system. Then, the amplifier, filter circuit, analog digital conversion processing and instrument display circuit are designed, simulated and tested. Finally a microwave power detection system based on microwave power sensor is designed, and the accuracy of the system is verified by Fluke digital. Using the microwave power detection system, the relationship between the input power and the output voltage of the 2 microwave power sensors at 4 different frequency points is studied. It is found that the amplification factor of the microwave power sensor with low power is gradually increased when input power is higher than a threshold value, and the amplification factor is constant at the design value in 0-100mW power. In view of this problem, this paper makes a theoretical explanation. This conclusion can better optimize the microwave power detection system designed in this paper.The first chapter is the introduction, mainly about the background and significance of the research topic, MEMS and RF MEMS, and microwave power sensor some basic theory, and research status of microwave power detection were summarized and classified, leads the research content microwave power detection system based on microwave power sensor.In the second chapter, the structure and theory of MEMS microwave power sensor are introduced, the principle of thermoelectric conversion and some characteristics of coplanar waveguide and the principle of heat transfer are also introduced.The third chapter and the fourth chapter is the main content of this thesis. The thermoelectric MEMS microwave power sensor based on the MEMS technology and compatible with MMIC GaAs technology has been analyzed in the third chapter. the sensitivity and signal to noise ratio of the microwave power sensor are studied, simulated and tested. The results obtained can be convenient for us to choose the low signal to noise ratio of the microwave power sensor. The MEMS microwave power sensor with low signal to noise ratio is very important for the post-stage amplifier. In the fourth chapter, the amplification and filter circuit of the detection system is simulated by Multisim software. According to the simulation results, the amplifier and filter circuit is designed and the PCB board is made. And then the module part and the meter display part are designed. The detection system based on microwave power sensor is composed of several parts. Then on the experimental platform of the research group of the detection system were tested, the detection system in the working state data and fluke digital million with data in the table were compared, can verify the design of the detection system of the accuracy of 99%. Finally in this paper, the design of the microwave power detection system based on to study two (4 of the thermocouple,12 of the thermocouple) microwave power sensor in four different frequency (1GHz, 10GHz and 20GHz,30 GHz) and three magnification (10 times,100 times,19.5 times) between the input power and output voltage relationship.12 thermocouple of the microwave power sensor in the 1GHz input power of 100mW when the output voltage is 1.1194V, the output voltage has reached V level, the amplified data accurate to the fourth point. Test results show that the detection system has the characteristics of high gain, stability and accuracy. The above 3 different times (10 times,100 times,19.5 times) for amplification, the output voltage and input power have good linearity, which shows that the detection system has a very stable amplifier gain. It is found that when input power is low in the 0-100mW, the amplification factor of the microwave power sensor is increased gradually. When reaching to 15mW larger than a threshold value, the amplification factor is constant at the design value. In view of this problem, this paper makes a theoretical explanation. This conclusion can better optimize the microwave power detection system designed in this paper.The fifth chapter is the main work of this thesis is summarized, and put forward the improvement direction based on the optimization of microwave power sensor of microwave power detection system, such as wireless receiving microwave power, portable power for the acquisition.The innovation of this paper:a microwave power detection system based on the microwave power sensor is designed.