Abstract: Tomographic imaging of biological tissue is achieved through a microwave imaging system and associated methods. An array of antennas are positioned in an illumination tank to surround biological tissue to be imaged. A liquid coupling medium is placed in the illumination tank, and the biological tissue is immersed in the medium. The array of antennas transmit and receive microwave-frequency RF signals that are propagated through the biological tissue. A signal processor is coupled to the antennas to process a demodulated signal representative of the microwave-frequency RF signal received by one or more of the antennas to produce scattered field magnitude and phase signal projections of the biological tissue. These projections may be used to reconstruct a conductivity and permittivity image across an imaged section of the biological tissue to identify the locations of different tissue types (e.g., normal versus malignant or cancerous) within the biological tissue.

Abstract: An improved method and apparatus for microwave imaging of an inhomogeneous target, in particular of biological tissue, compensates for the interactions between active antennae and nonactive antennae. Measured electric field data are processed in magnitude and phase form so that unwrapped phase information may be used directly in the image reconstruction. Initial finite element measurements and calculations are used to determine the perimeter dimensions of the target being examined, resulting in more accurate image reconstructions. An improved regularization technique is a hybrid of a Marquardt regularization scheme with a spatial filtering technique and a Tikhonov regularization scheme. An improved switching matrix enables simultaneous sampling of electric field data from a plurality of receiving antennae.