A mode matching - Bessel functions based approach for UWB microwave imaging

Microwave imaging has generated considerable attention in the last decade, especially for its applicability to breast cancer detection. Addressing such an imaging problem involves estimating the distribution of the field within a volume V based upon observations of the field on the surface of V, and this involves estimating the distribution of dielectric properties within the target volume. Current research in microwave breast imaging can be divided mainly into microwave tomography [1] and ultrawideband (UWB) radar techniques [2]. In tomographic image reconstruction, a nonlinear inverse scattering problem must be solved to recover an image of the dielectric properties in the breast. In contrast to tomography, the UWB radar approach solves a simpler computational problem by seeking only to identify the significant scatterers. In order to reconstruct the image, beamforming techniques of varying complexity are required. Presented here is a new method for the imaging of cylindrically-shaped objectsi. The method is based on a mode-matching (MM) procedure of Bessel functions, and it enables the presence and location of significant scatterers within an illuminated volume to be identified. Validation of the technique through both simulations and measurements has been performed and results are presented in this paper, illustrating the effectiveness of the method.