Near-field excitation modeling in microwave tomography

Abstract

In Microwave Tomography (MWT), a significant hindrance to image convergence is modeling error in the MWT algorithm. Modeling error is the failure of the forward solver to accurately model the physical reality of the MWT system. This leads to reduced fitness values of optimal solutions, and in the worst case scenario, can cause convergence to non-real solutions. A significant source of modeling error introduced into the forward solver is the assumption that illuminating radiation is sufficiently in the far-field to be modeled as a uniform plane wave. Due to close proximity of the antennas and imaging target in most MWT implementations to date, this assumption may be invalid. While the simulation of the antennas in the forward solver would ameliorate this problem, this would lead to intractable simulation times. By running a single simulation of the transmitting antenna, this significant source of modeling error can be rectified without increasing the forward solver's run-time significantly.