Slow-Wave MEMS Phase Shifter with Liquid Crystal for Reconfigurable 5G

Antenna beamforming is crucial for the development of 5G technology in the millimeter wave region and typical beamforming configuration uses phased arrays devices. For this reason, the development of phase shifters devices with low-cost, small footprint and high Figure of Merit (FoM) is necessary. In this paper, we present a slow-wave phase shifter based on a nanoporous alumina interposer, MEMS and liquid crystal (LC) for 5G mmW base station beamforming applications. The slow-wave line allows a device miniaturization, while the liquid crystal increases the phase shift and reduces the MEMS actuation voltage. A FoM of 42°/dB and 66°/dB was obtained at 24 GHz and 40 GHz, with a maximum biasing voltage of 50 V and a footprint of 0.13 mm². This device is a prime candidate for phased array antenna applications on 5G and future 6G base stations.