Frequency multiplexed metasurface for polarization conversion in full-space

In order to solve the problem of a single function in passive metasurface, a frequency multiplexed metasurface using full-space to realize different polarization conversion modes is proposed. On the basis of the fundamental theory of metasurface polarization transformation, a spliced coupling of multilayer structures was utilized. A compact architecture of five metallic layers and four dielectric layers was fabricated, and the principle analysis of polarization transformation was also performed. In the metallic part, two layers of oblique arrows and one layer of oblique rectangular patches constitute a low-frequency transmission structure, one layer of cross-shaped patches are constituted a high-frequency reflection structure, and one layer of rectangular patches constitutes an intermediate filter structure. Thus, it achieves a variable frequency polarization multiplexing function for transmission on one side and reflection on the opposite one. When the x- and y-polarized waves in the 6.3 GHz-8 GHz band are incident on the low-frequency unit side, they are converted into left-and right-hand circularly polarized transmitted waves, respectively. The axial ratio is less than 3 dB, and the transmission amplitude is up to 0.84 and 0.8. When 45 degrees linearly polarization incident waves in 16.4 GHz-16.8 GHz and 16.9 GHz-18 GHz bands impinge on the high-frequency unit side, the cross-polarized wave reflection is realized. The measured and simulated results are in good agreement. The metasurface proposed in this paper has potential applications in communication frequency multiplexing and multifunctional integration.