Time-Reversal Radar Technique for Resonance Detection in Multipath Environments

Abstract

This research investigates Time-Reversal (TR) methods for detecting the resonances of passive microwave structures contained in a multipath environment. The multipath environment is realized using a reverberant, 3D, microwave cavity with irregularly-shaped metal boundary walls. The experimental setup utilized MATLAB automation to link an arbitrary waveform generator (AWG) with a real-time oscilloscope for repeated signal transmission and acquisition and TR operations inside the reverberant cavity. To demonstrate the technique, two C-band microstrip patch antennas with distinct resonant frequencies were designed, fabricated, and considered as the Device Under Test (DUT). The developed method shows that time-domain TR processing can recover the resonant response of passive structures, including both amplitude and phase information, through adaptive processing. To date, there has been no experimental validation of resonance detection utilizing time-domain TR within a deliberately wave-chaotic electromagnetic enclosure—where multipath propagation, modal overlap, and environmental loading predominantly influence the system response. The results highlight the potential of time-domain TR as a practical tool for radar sensing, passive resonance measurement, and EMI/EMC testing in complex electromagnetic environments.