Frequency-diverse reflection metasurface antenna design for computational microwave imaging

In this paper, the design of a computational microwave imaging (CMI) oriented frequency diverse reflection metasurface antenna (FDRMA) is presented. Designing a FDRMA for CMI requires a careful synthesis framework, from the topology of metamaterial elements to the statistical analyses of the metasurface and the evaluation of its CMI performance. Consequently, we begin with an investigation of different metamaterial element topologies with the aim to choose the optimal one to constitute a desired reflection metasurface. The FDRMA is then designed by randomly distributing the metamaterial elements with diverse structural parameters. The orthogonality of the reflected field patterns is investigated by means of a spatial-correlation evaluation and a singular value decomposition. To mitigate random errors, each type of FDRMA is replicated 20 times, and the evaluation indexes are averaged. Finally, theCMI experiments are carried out through full-wave simulations using different FDRMAs to verify their computational imaging performance. Moreover, a prototype of the optimal FDRMA topology is fabricated and real CMI experiments are implemented to validate the proposed design method.