Single Antenna Continuous Wave Doppler Radar Detection for Multiple Moving Targets

Abstract

Wireless health monitoring and life-sign identification is possible via detection of human respiration activity using Doppler radar. The respiration rates of two people can be separated by the measurement of chest-wall dynamic motion, using a single-antenna 2.4 GHz continuous wave (CW) quadrature transceiver. Signal processing is used to separate the respiration rates of two targets, by observing correspondence to null and optimum points in the In-phase (I) and Quadrature (Q) channels of the transceiver. Experimental data in the single-antenna system is verified by comparison against simulated data of two moving targets wherein the reference point of one target is shifted in the simulation by introduction of a phase shift. This shows it is possible to use a non-contact measurement to distinguish between the respiration rates of two human targets by observing the I & Q frequency spectrums.