Multistatic microwave imaging with arrays of planar cavities

The authors present a multistatic imaging system at microwave frequencies based on arrays of planar cavity sub‐apertures, or panels. The cavity imager consists of sets of transmit and receive panels, loaded with radiating irises distributed over the sub‐apertures in an aperiodic pattern. This frequency‐diverse aperture produces distinct radiation patterns as a function of frequency that encode scene information onto a set of measurements; images are subsequently reconstructed using computational imaging approaches. Similar to previously reported computational imaging systems, the cavity‐based imager presents a simple system architecture, minimising the number and expense of components required in traditional microwave imaging systems. The cavity imager builds on previous frequency‐diverse approaches, such as the recently reported metamaterial and air‐filled cavity systems, by utilising frequency‐diverse panels for both the transmit and receive sub‐apertures of the imaging system. Though the panel‐to‐panel architecture has greater sensitivity to calibration error, this implementation nevertheless increases mode diversity and, in the context of a computational imaging system, results in improved image reconstructions.