Dielectric Constant and Loss Tangent in LiNbO Crystals from 90 to 147 GHz

The complex dielectric constant epsilon(omega) of single-crystal LiNbO sub (3) has been measured from 90 to 147 GHz using a reflectometer bridge. Electric field polarizations along both the ordinary and extraordinary axes were studied. The real part of epsilon(omega) drops slightly and the loss tangent increases ~ 12% across this frequency band. The data is used to model the dissipative losses of a simple co-planar waveguide of the type used in an electro-optic modulator.