A Real-Time 2.4-GHz Doppler Radar System with All Functionalities on Board for Vital Signal Detection

The protype of a 2.4-GHz zero-IF Doppler radar system with all functionalities on board for real-time vital sign detection is implemented and presented in this paper. The radar system accomplishes RF front end, base-band analog processing, analog-to-digital conversion, digital signal processing for the vital-sign signal extraction and the numeric and graphic result display. In the system, a Sallen-Key filter and a FPGA development board are used to remove interferences, adjust gain, and collect and process raw data. Experiments show that the respiration and heartbeat can be clearly detected when a person sitting at 1 meter away from the proposed radar. Both the realtime waveform and spectrum analysis are displayed on a separate LCD through an VGA interface.