mm-Wave Low Insertion Loss SIW Phase Shifter Based on Liquid Metal Technology

This letter presents the proof of concept of first liquid metal (LM)-based millimeter-wave (mm-wave) phase shifter that have very low insertion loss (IL) performance. The proposed phase shifter has a phase shift up to 360° with a phase resolution of 45°. The phase shifter operates on 26-GHz 5G band and have IL performance of lower than 2.1 dB. This enables the proposed phase shifters to have an excellent figure of merit (FoM) of 174.7°/dB at 26 GHz. The proposed phase shifter has several advantages including the capability to be integrated with SIW-based feeding network for mm-wave phased array antennas. The phase of the phase shifters is controlled by introducing vias formed of LM. When the via is required, the via hole is filled with LM, and when the via is no longer required, the holes are emptied of LM. The proposed reconfiguration approach will also be applicable within a wide range of different reconfigurable mm-wave devices.