Design Of Blood Flow Rate Detector Based On Microwave Technology

The blood flow rate can provide auxiliary information for the diagnosis of Cardiovascular diseases. Using the technique of microwave and radio frequency (RF), this paper designs a blood rate microwave detector, which is used to detect the rate of blood in the superficial vessels or the ones that can be seen by eyes. The detector mainly consists of antenna probe, RF transceiver module, Doppler signals collecting and disposing module, and power. The main research contents include the following parts:designing RF transceiver module, designing of normal mode helical antenna and processing microwave Doppler signal.In the first part, the RF transceiver module which detects the Doppler signals with coherent detection technique is designed. The criterion of selecting each semiconductor component and the electrical parameter in the transceiver module are also discussed. Moreover, two kinds of signal source schemes are proposed, and a real radio frequency transceiver module is made, circuit functional is also detected. In the second part, a miniature helical antenna is researched. According to the needs of antenna radiation and impedance characteristic, the screw diameter, pitch and number of turns are selected in order to meet the requirement of submitting and receiving microwave or radio frequency signals. A miniature helical antenna which meets the requirement of the system is designed. The results of antenna simulation and detection are proposed. In the third part, the extracting of Doppler signal's time-frequency distribution (TFD) and the estimate of its instantaneous frequency are studied, meanwhile, a simulated non-stationary signals is processed. The detector is used to detect the flow rate of water and human blood in order to verify its function.The features and innovation of this paper are as follow:●Using microwave/RF technology, a blood flow rate detector which is scatheless is designed, which will provide medical diagnostics with a new technique.●A RF transceiver module is designed to detect the Doppler signals with coherent detection technique.●A small helical antenna which can be used to receive and send signals is designed. By debugging the antenna and RF transceiver module, the system can detect weak Doppler signals.●Using Cohen time-frequency analysis technique to extract the TFD of microwave Doppler signals.