Research And Application Of Six-port Circuit In Microwave Wireless Detection System

The six-port(six-port)circuit is widely used in many fields due to its advantages of flexible architecture,easy design,small size,light weight,low power consumption and ease of integration.At present,the six-port circuits have played a significant role in many popular applications such as vital signs detection,ultra-wideband wireless communication receivers,and so on.Therefore,the study of six-port technology is significant.Due to six-port junctions' variety(typically composed of power dividers,couplers,and phase shifters),the performance of the entire six-port junction is important.The higher resolution,wider bandwidth and more bands of the radar are required.The reflectometers also need higher accuracy.They challenge those six-port system.Six-port circuits with better performance are in need.In consideration of these,this paper mainly studies the realization of the microstrip six-port junction and different types of six-port junction are designed.The research contents of this paper are as follows:1.Some basic theories and applications of six-port was introduced.The error of six-port was analyzed.Two basic six-port junctions working at 24GHz were designed and simulated.2.A dual-frequency six-port junction was designed for vital sign radar.The dual-band six-port junction meets the requirement of solving the zero-point detection of vital signals.3.A broadband six-port junction for high-resolution radar was designed,simulated and fabricated.Its center frequency is 3.52GHz with 53.7%relative bandwidth.4.A six-port junction for LFMCR high sensitivity radar is designed to improve the transceiver isolation.The center frequency measured is 2.75GHz,the maximum isolation is 43dB.The designed six port junction meets the needs of high transceiver isolation,and it can greatly enhance the sensitivity of chirp radar performance.5.The six-port junction used in high-precision reflectometer was studied,and the six port junction was designed,fabricated and measured.The three coupling probes satisfy the relationship,so that the power of the signal input source coupled to the detection module is V2 times the power of the input end of the load under test coupled to the detection module.Thus,the six port junction achieves uniform distribution around the origin of the complex reflection coefficient plane,which meets the requirements of high-precision reflection meter application.