Signal Selection for Contrast-Enhanced UWB Microwave Radar Imaging With Inhomogeneous Breast Phantoms

A modified imaging method that presents reduced clutter images using inhomogeneous (complex) breast phantom is presented in this letter. A contrast-enhanced imaging scenario is assumed in our investigations. To approximate dense heterogeneous breast tissues, three randomly shaped scatters with high dielectric constant are placed in the breast phantom. Two tumor-like inclusions with different dielectric constants were used to approximate a contrast-enhanced imaging scenario in our measurements. Through differential imaging, the tumor can be localized successfully with the 31-element antenna array. If fewer antennas are selected in a next step, the image quality can be improved, and clutter can be reduced. The improvement in the image has been achieved by reducing the number of antennas used in focusing from 31 to 20, 15 and 10 elements, selecting only the antennas that are nearest to the tumor location. Results show that the level of clutter energy is reduced to 1/14 of its original value. Detailed study is provided to show the effect of using different combinations of antennas around and away from the target location. The proposed method is applicable to any phantom. However, within the framework of this letter, it is validated considering an inhomogeneous phantom.