Evaluation of approximate analytical solutions for EMI scattering from finite objects of different shapes and properties

UWB electromagnetic induction (EMI) sensing, from 10s of Hz up to 100s of kHz, is emerging as one of the most promising remote sensing technologies for discrimination of subsurface metallic objects. Progress is urgently needed to distinguish dangerous objects, such as unexploded ordnance, from innocuous clutter. Development of EMI signal calibration, interpretation, processing, and inversion have all been impeded by the lack of rigorous, reliable analytical solutions for any scatterer shape other than the sphere. Here we test a number of new approximate solutions and determine that most canonical geometries and common, homogeneous material compositions can be treated adequately by the simple formulations proposed.