Twisted nematic liquid crystal for fast-response reconfigurable microwave applications

Abstract Ultralow latency is an essential requirement in future wireless networks. It is mainly attributed to response time of reconfigurable devices such as phase shifters. Liquid Crystals (LC) can be used for such devices to achieve tunability with two distinct modes—Anti-Parallel (AP) and Twisted Nematic (TN). The mechanism between orientation of LC molecules and response time was investigated. LC with TN configuration turns out to have a faster response time than the more conventional use of AP. A phase shifter design operating in the frequency range of X-band was examined by carrying out the two schemes for initial LC molecules anchoring. We investigated the influence of these configurations on key performance metrics including the response time and the maximum differential phase shift, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>ϕ</mml:mi> <mml:mrow> <mml:mtext>max</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> . Experimental results consolidated that the TN configuration reduced the response time by 50% and decreased the differential phase shift, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>ϕ</mml:mi> <mml:mrow> <mml:mtext>max</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , by 32% than the AP configuration. The reason behind it was explained with a theoretical inference. The findings unleashed potential of LC-based phase shifters with a TN configuration for applications where a small latency time is desired.