Time-Domain Characterization of Nematic Liquid Crystals Using Additive Manufacturing Microstrip Lines

This paper presents a method for effectively characterizing the dielectric permittivity of nematic liquid crystals across a broad frequency range. These materials show significant potential for reconfigurable devices operating in microwave and millimeter-wave frequencies. To achieve this goal, an additive manufacturing technique is used to create a microstrip line that can be filled with liquid that acts as its substrate. The liquid crystal (LC) is then biased to modulate its permittivity. After manufacturing, a time-gating approach is used to extract the permittivity, eliminating the need for in-fixture calibration, such as Thru-Reflect-Line (TRL). Finally, the approach is validated through simulations and experimental results, which closely align with those reported using other methods in the bibliography.