Electromagnetic scattering-based array processing methods for near-field object characterization

摘要

We consider the use of high resolution array processing methods for detecting and localizing near-field extended targets for measurement geometries in which an array of electromagnetic receivers observes the fields scattered by the objects in response to a plane wave illumination. The algorithms presented here modify the conventional direction finding array processing techniques and use the spatial complexities of fields to determine both the range and the bearing of the targets in the region of interest. In contrast to previous source localization problems, we employ electromagnetic scattering models parameterized explicitly in terms of the target positions and which account for all multiple scattering effects. These models play an integral role in allowing us to compute explicitly the analytical expressions for the Cramer-Rao bounds (CRB) for position estimates. The Cramer-Rao bounds gives the lower bound for the estimates, and thus, specifies the lowest possible error variance that can be attained with an unbiased estimator. The theoretical values are then verified using Monte-Carlo simulated error variances. [References: 23]