A Low Power 5.8-GHz ISM-Band Intermodulation Radar System for Target Motion Discrimination

This paper discusses the design and test of an intermodulation radar receiver and a nonlinear tag operating in the 5.8-GHz industrial, scientific, and medical (ISM) band. To discriminate reflections of the target-generated 3^rd-order intermodulation frequencies from the clutter-reflected fundamental tones, the receiver was designed to attenuate the fundamental reflections and amplify the lower 3^rd-order tone generated by the nonlinear target. The nonlinear tag was designed on a flexible substrate for wearable applications. Experiments were performed with two types of targets, i.e., the nonlinear tag and a metal reflector. Various experiments were performed to demonstrate the clutter rejection capability of the radar, i.e., mechanical motion and vital sign detection of a human target in the presence of multiple clutter. Four experiments were recorded and analyzed in this paper. The results were recorded and analyzed to demonstrate the clutter noise rejection capability of the intermodulation radar.