Design and Implementation of a THz Anisotropic Metamaterial
Polarization Regulator
LI Yan-hong1, LIAO Meng-meng2, FENG Jie3
1. School of Physics & Electronic Engineering, Xianyang Normal University, Xianyang 712000, China
2. School of Information and Electronics, Beijing Institute of Technology，Beijing 100081, China
3. School of Communication Engineering, Xidian University，Xi'an 710071, China
Abstract：Electromagnetic wave polarization will affect the performance of the wireless communication system. With the wide application of electromagnetic fields and microwave technology, free control of the electromagnetic wave polarization to meet the demand for information transmission and access to information becomes very important. It is also important to realize free control of polarization by changing the polarization state in wireless communication and radar target recognition. Compared with microwave communication, terahertz communication has the advantages of richer spectrum resources and higher transmission rates with shorter wavelengths. However, the traditional polarization governor has not been well applied in terahertz communication due to someproblems. This paper has designed a model applicable to the double function of terahertz spectrum polarization governor by using anisotropic metamaterial. First, the coordinate decomposition method is used to analyze the components of the double function of polarization control features, and the analysis results have revealed that the designed controller can realize linear polarization wave control as well as circularly polarized wave control, which is featured by double function control. Then, the surface current method is adopted to analyze the polarization conversion mechanism of the governor. The simulation results have shown that the governor has four resonant points, and the superposition of the fourth order electromagnetic resonance occurs in the metamaterials unit structure, which makes the governor work in a wide frequency band and has a high polarization conversion efficiency. Within the frequency band of 0.45～1.152 THz the efficiency can reach more than 90%. Finally, the effects of different device parameters on their performance are analyzed, and the governor's optimization and actual application conditions are proposed. Through the analysis of structural parameters, it is found that the change of structural parameters will affect the band width of the governor as well as the distribution of the resonance point location. The governor has exclusive performance with their working frequency band width. The governor has a poor performance with wider frequency bandwidth and vice versa. In the practical application of the governor, the structural parameters should be optimized and adjusted according to the specific regulation requirements to obtain satisfactory control features. Through the analysis of incident angle and azimuth angle, it is found that the performance of the governor is very sensitive to the change of incident Angle, and it is pointed out that the governor should be positioned in such a way that the projection of incident wave in the governor is parallel to the edge of the governor. Compared with previous work, the regulatordesigned in this paper has a more efficient performance and simpler structure, and the dual-function characteristics make the use of devices more convenient and diversified. This work provides theoretical reference for developing and applying terahertz polarized regulator.
Key words：Regulator; Anisotropic metamaterials; Dual function regulation; Polarization conversion rate
