Digital Metamaterial of Arbitrary Base Based on Voltage Tunable Liquid Crystal

In this chapter, we introduce nematic liquid crystal (NLC) as a means to develop novel metamaterials - namely, multifunctional digital metamaterials of arbitrary base. To accomplish this, we design general coding elements or codes of specific bases by carefully selecting appropriate NLC and designing the geometrical configuration. Switching between custom applications corresponding to different coding patterns is made simple. We propose a proof-of-concept prototype consisting of a superstrate of quartz, an array of metallic patches, a substrate of NLC, and a ground. Encoding is achieved by biasing NLC to shift the phase of incoming waves. The novel coding mechanism has been proven through both numerical simulation and preliminary experiments. We present two representative applications of different bases - base-4 beam steering and base-2 RCS reduction - to demonstrate the novelty of the digital metamaterial. The coding freedom of the NLC-based digital metamaterial is clearly demonstrated.