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 paper. 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. Firstly, 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 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 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.