Systematic investigation of molecular structure of nematic-phase liquid crystals for reduction of dielectric loss in microwave control applications

For realization of phase shifting using a liquid crystal (LC) that can continuously control the phase of microwaves, we evaluated the relationship between the molecular structure of the LC, which assumes a nematic phase at room temperature, and the dielectric loss in microwave frequency. The results indicated that the LC has a rigid molecular structure, has fluorine as a polar group, and is in a low temperature, leading to lower dielectric loss. From these results, we considered that dielectric loss can be reduced by suppression of the thermal vibration of LC molecules under microwave exposure.