Optimizing Dielectric-Metal-Dielectric Spacing in Strip-Line Phase Shifters with Liquid Crystals for Enhanced Figure-of-Merit at 60 GHz

This paper investigates the design and optimization of liquid crystal (LC)-filled strip-line phase shifters (SL-PS) for advanced communication systems, with a focus on performance enhancement for the 60 GHz frequency range. The study presents a comprehensive analysis of key performance metrics, including maximum differential phase shift (DPS), insertion loss (IL), and figure of merit (FoM), with a particular emphasis on the dielectric spacing. Simulation results indicate that, for optimal performance, the LC-filled SL-PS achieves a maximum DPS of 179.62° at 60 GHz, a maximum insertion loss of 1.36 dB, and a FoM of 132.39°/dB (30°/dB higher than that of the optimized coaxial phase shifter with the same LC). The SL-PS design employs a dielectric spacing of 0.19 mm and a core width of 0.22 mm, with the line length calculated to be 10.654 mm to achieve a maximum DPS of π. The study further explores the challenges associated with device mounting, alignment, and the integration of liquid crystals, highlighting the need for future work to address these issues through experimental validation. The proposed FoM-enhanced design offers significant potential for integration into nextgeneration communication systems, offering advantages in terms of insertion loss mitigation and electromagnetic shielding.