Accuracy evaluation of asymptotic methods for the electromagnetic simulation of personnel security screening

Cutting-edge personnel security screening relies on microwave imaging, where addressing future security demands entails integrating digital twins into development and testing processes. To create a realistic digital twin for microwave imaging systems, accurate replication of microwave images obtained from scanning real individuals is crucial, achieved through electromagnetic simulation. Employing fast simulation methods reduces the computational load to a viable level, yet it introduces some computational inaccuracies due to underlying approximations. The extent to which these inaccuracies affect microwave images is often unclear, while digital twins are already being used. To thoroughly assess this unknown influence, the simulation results obtained with physical optics (PO) and geometrical optics (GO) are compared with an integral equation (IE) solution approach using two scenarios of a walk-through personnel security screening in the frequency band below 10.6 GHz. Remarkably, while radar images are highly similar, raw signals exhibit significant deviations. Thus, for radar image simulation, PO and GO appear sufficiently accurate, offering attractive runtimes below two minutes per simulation. Conversely, the IE method proves impractical in many situations, as a single image necessitates over three weeks of computations.