A multifunctional metasurface with asymmetric transmission and high-efficiency cross-polarization converter

Abstract

A three-layer multifunctional metasurface structure is proposed to achieve polarization rotation, perfect polarization conversion, and asymmetric transmission. The design consists of mutually perpendicular rectangular patches, metal pillars, and open-slit metal sheets. By propagating the current through the metal pillars and changing the surface current direction, the dipole can be orthogonally steered to accomplish polarization conversion. The metal in the middle layer can be used to both improve the polarization conversion ratio and ensure high transmittance. The operating band of asymmetric transmission is 8.3–14.7 GHz, where the conversion ratio is above 90% in all of 9–14.2 GHz. In order to verify the proposed concept, the related parameters are designed and measured, the final experimental results match with the simulation results, and the design can be used in the radome, electromagnetic stealth.

An ultra-thin multifunctional chiral metasurface with asymmetric transmission, cross-polarization conversion, and circular dichroism for Ku- and K-band applications

“…In [29] and [32], the designed metasurfaces had an ultra-thin thickness but were not multifunctional; the authors claimed only AT. The metasurfaces in [41] and [42] had a high thickness and claimed to be multifunctional, but the operation of CD was not achieved, and they also had a lower transmission percentage. On the basis of these works, our proposed chiral metasurface achieves up to 60 • angular stable multifunctional operations, also including CD in the microwave regime.…”

“…Assuming a 2D planar structure is placed in the x-y plane, the incident and transmitted EM waves propagating in the zdirection can be expressed as [42] E i (r, t) = I x I y e j(kz−wt) (1)…”

“…In order to find the phase and polarization state of the transmitted wave, the product of the Jones matrix of incident and transmitted waves can be calculated. Thus, the Jones matrix that shows the relationship between incident and transmitted waves can be written as [42…”

“…Using equations ( 4) and ( 5), the AT property can be calculated by finding the difference between the total transmission of the forward and backward EM wave transmission. For xand y-polarized EM waves, the AT parameters can be obtained as [41][42][43][44]…”

“…A graphene chiral metasurface was presented to realize CD with a high efficiency of 87% [37]. [41][42][43] demonstrated the multifunctionality of chiral metasurfaces, but the designs were not angularly stable for each function, and they achieved two functions of CPC and AT using the same metasurface.…”