A Review of Tunable Electromagnetic Metamaterials With Anisotropic Liquid Crystals

The performance of metamaterial is limited to a designed narrow band due to its resonant nature, it is highly desirable to incorporate active inclusions in metamaterials to extend the operation bandwidth. This review summarizes the development in realizing the tunability of electromagnetic response in metamaterials incorporated with nematic liquid crystal (LC). From rigorous comparison, it is found that the anisotropic property of nematic LC is essential in predicting the influence of LC molecular director orientation on the resonant frequency of metamaterials. By carefully designing the metamaterials and properly infiltrating LC, the operation frequency of single/double negative parameters of metamaterials can be dynamically modulated with remarkable red/blue-shift, depending on the LC molecular orientation angle. Moreover, the recent liquid crystal-based developments and novel applications are investigated and highlighted.

Automated summary

The incorporation of nematic liquid crystal in metamaterials enables the tunability of electromagnetic response, with the anisotropic nature of liquid crystal playing a crucial role in influencing the resonant frequency. By carefully designing and infiltrating liquid crystal, the operation frequency of metamaterials can be dynamically modulated, resulting in remarkable red/blue-shift. Recent developments and novel applications of liquid crystal-based metamaterials are also investigated and highlighted.