Passive millimeter-wave imaging with extended depth of field and sparse data

In this paper, we introduce a new millimeter wave imaging modality with extended depth-of-field that provides diffraction limited images based on a significant reduction in scan-time. The technique uses a cubic phase element in the pupil of the system and a nonlinear recovery algorithm to produce images that are insensitive to object distance. We present experimental results that validate system performance and demonstrate a greater than four-fold increase in depth-of-field with a reduction in scan-time by a factor of at least two.