A frequency domain MVDR beamformer for UWB microwave breast cancer imaging in dispersive mediums

In this paper a new imaging technique for early stage ultra wideband (UWB) microwave breast cancer detection is proposed. A circular array of antennas illuminates the breast tissue with UWB pulses and the backscattered signals are then passed through a beamformer designed and applied in frequency domain. This design enables the beamformer to compensate for non-integer delays and frequency dependent dispersion and at the same time increases the accuracy of the beamformer. It is shown that the proposed imaging algorithm reduces the computational cost and memory of the imaging system by decreasing the sampling rate to the Nyquist rate and significantly reducing the number of required matrix inversions. Furthermore, the proposed algorithm significantly improves the quality of the obtained image and on average the signal-to-clutter ratio of the image is increased by 89.29% compared to other cases.