Active Microwave Sensors for Complex Natural Resonance-Based Object Detection
Simulation of Complex Natural Resonances (CNR) of objects with commercially available finite element software products, such as CST Microwave Studio, is a valuable tool. The human body and any background objects scatter any microwaves used for person screening; this effect provides the major difficulty in implementing a reliable screening system using the CNRs of objects. The inherent diffraction of microwaves of several hundred MHz around the human body prevents the late time response (LTR) of a person being composed entirely of the LTR of any objects carried. Further difficulties arise from the necessity of removing the scattered contribution from objects in the immediate vicinity of any person being screened by microwave excitation of CNRs. Reflections from background clutter can be time gated if they arise from objects that are separated from the person by a sufficient distance, so that the reflections do not overlap the LTR from the body.