A Multi-illumination Multi-frequency Approach for Early Detection of Breast Tumor by Mode-Matching Method

Microwave imaging is the technique used to analyze hidden objects in a structure using microwaves. The significant contrast in dielectric properties between the malignant tumors and normal fatty tissue at microwave frequencies is the driving force in the application of microwave imaging for breast tumor detection. In this paper breast is modelled as a hemisphere and spherical tumors are embedded in the breast, which is divided into different layers. Multiple receivers are placed around the composite structure for each layer and measurements are carried out at different microwave frequencies. Hence a multi-illumination and multi-frequency approach is employed for collecting scattered field, which helps in reconstruction of entire permittivity profile. The scattered field from the breast tumor model were computed by using a boundary value mode-matching (MM) approach. Then the intensity of field inside the composite structure for each layer is reconstructed from the scattered field by mode-matching Bessel function method, which is used to analyze hidden or embedded tumor. It is identified that microwave frequency range used for imaging has dependence on the permittivity of normal tissue. A new algorithm is proposed to identify the exact permittivity of the normal tissue. Further the optimum frequency range has been identified corresponding to each permittivity value. An attempt has been made to identify the minimum number of receivers required for efficient reconstruction of permittivity profile.