Non-Contact and Real-Time Pulse-Based Radar with Sensitivity Improvement for Vital-Sign Monitoring

A real-time pulse-based sensing radar with an adjusted transmitting power for long-term monitoring application is presented to detect vital-sign information from subjects. The radar using the technique of pulse width modulation in the transmitter helps adjust sensing energy, which in turn improves the overall signal-to-noise ratio (SNR), thereby increasing sensitivity in particular at the non-ideal sensing environment. To increase radar adaptability and verify its concept, we focus on two cases of different probing pulse width and expect to receive the echoes for monitoring respiration signal. The measured results show that the obtained SNR can indeed improve by altering the propagation pulses.