Dual-Polarized Frequency-Diverse Metaimager for Computational Polarimetric Imaging

A dual-polarized frequency-diverse metaimager (DFM) applicable for computational polarimetric imaging (CPI) is proposed in this article. The proposed DFM working from 18 to 22 GHz can generate spatially random measurement modes at different operating frequencies as well as under varying polarization states. The DFM is a low-profile metacavity etched with sparsely arrayed cross-shaped slots. First, a high-dispersion random metasurface consisting of 100 different kinds of elements is designed for the realization of frequency-diverse field distributions inside the metacavity. The simulated annealing (SA) algorithm is used to optimize the element positions. Additionally, the cross-shaped slot capable of working independently under two orthogonal polarization states is also designed, which facilitates low-correlated dual-polarized radiation. Then, the performance of the DFM is evaluated. The S11 of the DFM is under-10 dB, ensuring a good impedance match. In total, 100 dual-polarized measurement modes with correlation coefficients (CCs) smaller than 0.35 are obtained from 18 to 22 GHz. Finally, the DFM-based imaging experiments are implemented to verify the feasibility of the proposed DFM architecture. Comparative experiments are also carried out to demonstrate the advantage of leveraging dual-polarimetric information.