Parametric Flat Lenses for Near-Field Imaging and Electronic Beam Scanning

Conventional flat lenses are based on delay compensation which suffers from Ohmic loss. In this paper, the concept of the parametric flat lens is proposed and demonstrated with theoretical analyses and simulations. Based on the phase characteristics of parametric mixing, the parametric lens can diffract the near-field to form a focused image or steer the far-field electronically toward a focal point. The parametric mixing circuitry contained in each antenna element of the lens can achieve a moderate amount of conversion gain which can be applied to compensate for the loss of radiation efficiency or aperture efficiency. The design of a double-balanced parametric mixer is presented based on commercially off the shelf varactor diodes, which demonstrated the practicality of this approach.