Beamforming in the frequency domain with applications to microwave breast imaging

Delay and sum (DAS) beamforming is a common time domain technique used to reconstruct images from ultrawideband radar data. DAS is straightforward and fast, but requires careful selection of an appropriate time step. This paper presents a frequency domain formulation of the standard DAS algorithm. While mathematically equivalent to DAS, the frequency domain approach eliminates the dependence on time step and allows for a higher quality image from fewer data samples.