Low IF demodulation for physiological pulse Doppler radar

Quadrature receivers are employed in Doppler radar vital sign sensing to overcome position sensitivity issue of single channel receivers. However, quadrature architecture adds to the complexity of the system, and any imbalance between the two channels can introduce significant error in measurements. Pulse Doppler radar single channel receiver is investigated for extracting physiological signals. A low intermediate frequency demodulation method is employed to retrieve the physiological information. This architecture can take advantage of the benefits of a quadrature receiver without having the complexity and issues of such a receiver. Different motion patterns generated with a mechanical target and a human subject are investigated for proof of concept. This is the first reported use of low IF demodulation for pulse transceiver architecture for Doppler radar physiological sensing.