Dual-Wide-Band Dual Polarization Terahertz Linear to Circular Polarization Converters based on Bi-Layered Transmissive Metasurfaces

Abstract

Transmissive metasurface-based dual-wide-band dual circular polarized operation is needed to facilitate volume and size reduction along with polarization diversity for future THz wireless communication. In this paper, a novel dual-wide-band THz linear polarization to circular polarization (LP-to-CP) converter is proposed using transmissive metasurfaces. It converts incident X polarized waves into transmitted left-hand circular polarized (LHCP) and right-hand circular polarized (RHCP) waves at two frequency bands. The structure consists of bi-layered metasurfaces having an outer conductor square ring and three inner conductor squares diagonally intersecting each other. The proposed converter works equally well with incident Y polarizations. Operational bandwidths for the dual-band LP-to-CP are 1.16 THz to 1.634 THz (34% fractional bandwidth) and 3.935 THz to 5.29 THz (29% fractional bandwidth). The electromagnetic simulation was carried out in two industry-standard software packages, High Frequency Structure Simulator (HFSS) and Computer Simulation Technology (CST), using frequency and time domain solvers respectively. Close agreement between results depicts the validity and reliability of the proposed design. The idea is supported by equivalent circuits and physical mechanisms involved in the dual-wide-band dual polarization operation. The impact of different geometrical parameters of the unit cell on the performance of LP-to-CP operation is also investigated.

A VO2 film-based multifunctional metasurface in the terahertz band

“…As demonstrated in Fig. 3(a), for the normal incident y-polarized wave, the reflective wave of the converter can be expressed as [39,40] E r = E xr e x E yr e y = jR xy je iφ xy E xi e x jR yy je φ yy E yi e y ,…”

Inverse Design of a Dual-Band Reflective Polarizing Surface Using Generative Machine Learning

“…EM metasurfaces that convert linear polarization (LP) to circular polarization (CP) and vice versa, which we will simply refer to as polarizers, have attracted significant interest, especially in the microwave regime [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. This is because circular polarization is more effective than linear polarization for establishing and maintaining mobile communication links due to their robustness to channel-induced effects from absorption, cross-polarization interference, impaired line-of-sight paths, Faraday rotation effect due to the ionosphere, and multi-path propagation.…”

“…This is because circular polarization is more effective than linear polarization for establishing and maintaining mobile communication links due to their robustness to channel-induced effects from absorption, cross-polarization interference, impaired line-of-sight paths, Faraday rotation effect due to the ionosphere, and multi-path propagation. Polarizers can operate in reflection [3][4][5][6][7][8][9]17] or transmission mode [10][11][12][13][14][15][16], where the incident linearly-polarized wave is converted to a reflected or transmitted circularly-polarized wave, respectively. The transmissive polarizers are great solutions for integration with linearly-polarized antennas; however, they are usually composed of more than one layer of scatterers and can introduce insertion loss to the converted wave.…”

Simple Design of Broadband Polarizers Using Transmissive Metasurfaces for Dual Band Ku/Ka Band Applications

“…Furthermore, a dual-band polarization conversion operation is required for the merging of multiple systems to achieve adequate volume and size reductions. Thus, in the last couple of years, researchers have worked on dual-band polarizers [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] using multi-layered [ 24 , 29 , 31 ], bi-metallic layered [ 23 , 25 , 26 , 28 , 30 ], and single-layered structures [ 27 ].…”