Research On Microwave Radiometer Antenna For Human Body Temperature Measurement

The cardiac radiofrequency ablation surgery is an effective means for treating arrhythmias, but during the ablation procedure, low temperature in the ablation region will not achieve the curative ablation effect, while high temperature will burn the normal tissue. Furthermore, since the microwave has a certain penetration performance, thermal radiation signals from a certain depth in cardiac tissue can be received by microwave radiometer without damage, from which we can invert the temperature information. Therefore, it's a rewarding job to monitor the temperature of cardiac ablation zone by microwave radiometer in real time.Firstly this paper introduces the research background and significance of human body temperature measurement by medical microwave radiometer, as well as the status on scholars at home and abroad researching in medical radiometer and antenna, and analyzes and summarizes the patterns?electromagnetic characteristics of both. After, we expound the principle of temperature measurement by microwave radiometer, including the basic principles of microwave radiometry, the model of human body microwave radiation, the principles and types of temperature measurement radiometer and antenna. Then two kinds of 4GHz antenna are designed: one is dual-gap type, another is monopole bare probe cap type, and their electromagnetic characteristics and the impact on the electromagnetic properties of the antenna when loaded with ablation line are simulated. Finally, the monopole bare cap antenna is developed, and the antenna's bandwidth, resonant frequency and 11 S are tested. In order to verify the temperature measurement performance of the antenna, we use the C-band radiometer whose front is connected with monopole bare cap antenna to measure the different temperature of the water, and obtain the rate of change of output voltage with water temperature, which verifys that the radiometer system can perceive the changes of water temperature at a certain distance and has the ability to inverse it.Through the test of antenna parameters and the experiments of temperature measurements, the results show that: the monopole bare probe cap antenna can receive the thermal radiation signal from the water at a certain depth, and the antenna can meet the needs of application on the bandwidth, the resonance frequency and 11 S and other technical indicators. Therefore, the antenna designed has a good prospect in the respect of cardiac ablation zone temperature measurements.