Waveguide Microwave Imaging: Spherical Inclusion in a Dielectric Sample

A new 3-D microwave imaging technique is proposed for the detection of a position and size of a spherical object in a dielectric sample located in a waveguide system. The reconstruction is based on a radial basis function neural network inversion, backed by finite difference time domain analysis and requires only elementary measurements of complex reflection and transmission coefficients. Functionality of the technique is illustrated by computational experiments in reconstructing the parameters of a glass sphere and an air bubble in a rectangular Teflon block. It is shown that, at 915 MHz, the spheres of not less than 15 mm diameter are reconstructed with the average errors of 0.9%-2.2%.