Multigap-Waveguide Liquid Crystal Phase Shifter at Ka-Band

This letter presents for the first time an innovative waveguide structure, the multigap-waveguide (MGWG), utilizing liquid crystal (LC) technology to develop a continuously tunable phase shifter at Ka-band. In contrast to existing LC phase shifters, this design eliminates the need for polymer films or thin-film stepped impedance structures to control LC molecules. The inclusion of a gap waveguide flange ensures an individual electrical biasing of the four electrodes. The proposed design achieves a maximum differential phase of 281° in the frequency range from 24 to 38.5 GHz, with insertion losses ranging from 2.1 to 3.1 dB. The maximum figure of merit (FoM) is 105°/dB.