Measurement of the dielectric properties of various monoolein/ water mesophases between 90 and 140 GHz

In this paper, the dielectric properties of a series of glyceryl monoolein/ water liquid crystal systems containing 15, 20, 25, 30, 35, 40, 45, and 50 wt.-% water are measured between 90 and 140 GHz. An IEEE standard WR-08 waveguide shim is used as a sample holder. The holder is filled with the monoolein/water liquid crystal system during measurement. The S-parameters of the sample holder filled with the liquid crystal systems are measured using 90-140 GHz millimeter-wave test equipment. The dielectric properties of the crystal systems are extracted from the measured transmission parameters (S21) using the Newton algorithm. We find that the dielectric properties of these glyceryl monoolein/water liquid crystal systems from 90 GHz to 140 GHz are not sensitive to frequency. That is in contrast to the low-frequency dielectric properties in the literature. We also find that the imaginary component of the dielectric spectroscopy between 90 and 140 GHz can identify the phase of the monoolein/water liquid crystal system. The finds in this paper are important for monoolein study.