W-Band Characterization of Anisotropic Liquid Crystals at Room Temperature

This paper describes the characterization of Liquid Crystals (LCs) at W-Band using the standard WR-10 rectangular waveguide. The reflection parameter of a 10 mm long waveguide - terminated by a short-circuit - is measured. The LC is oriented with a homogeneous magnetostatic field strength of 400 A/mm, generated with an air-cooled coil. The extracted complex permittivity of the LC K15 from Merck KgaA (also known as 5CB) is presented, showing permittivities well below 3 with a dielectric anisotropy of Deltaepsiv<0.19 (equivalent to tau=Deltaepsiv/epsiv_max<8.5%) and dielectric losses less than tandelta<0.023, all at W-Band.