NRD waveguide-type terahertz phase shifter using nematic liquid crystal

摘要

Non-radiative dielectric (NRD) waveguides are known as a type of transmission line with advantages such as the restriction of undesired radiation at curved sections and discontinuities. A new type of terahertz phase shifter which uses liquid crystal as the dielectric material in an NRD waveguide is presented for the first time. The phase change is very large but the decay time is extremely long. By inserting a PET sheet into a nematic liquid crystal-loaded NRD waveguide, the thickness of the liquid crystal layer is reduced. Although the phase change decreases, the decay time is greatly improved, and the availability of the partial use of nematic liquid crystal in the dielectric material of an NRD waveguide is confirmed. By comparing dielectric response results of the ordinary sandwiched cells with the experimental results of nematic liquid crystal-loaded NRD waveguides, it is confirmed that the response time does not depend on the kind of device. (C) 2019 The Japan Society of Applied Physics