Whispering gallery modes in rutile resonators at millimeter wave frequencies

Whispering gallery modes in single crystal rutile resonator were measured at the frequency range 15-30 GHz. Predicted and measured values of resonant frequencies for several WGM were in excellent agreement. Permittivity components parallel and perpendicular to anisotropy axis have been evaluated and their values were /spl epsi//sub /spl perp//=85.8/spl plusmn/0.2% and /spl epsi//sub /spl par//=163.2/spl plusmn/0.2% at room temperature and frequencies 15-30 GHz. Dielectric loss tangent components of rutile measured at room temperature and frequency of 25 GHz were tan/spl delta//sub /spl perp//=4.2/spl times/10/sup -4//spl plusmn/10% and tan/spl delta//sub /spl par//=5.7/spl times/10/sup -4//spl plusmn/10%.