Yttrium iron garnet magnetically tunable magnetodielectric resonator for millimeter and submillimeter wavelength

Magnetic field tuning characteristics of a single-crystal yttrium-iron garnet magnetodielectric resonator in the frequency ranges 40-60 and 75-110 GHz are reported. It was experimentally confirmed, that magnetodielectric modes of such resonators are magnetically tunable by 1 GHz with relatively small magnetic field (less then 1.75 kOe). It was pointed that tuning rate and required field can be altered by properly selecting sample´s demagnetizing factor. Theoretical calculations on the basis of cylindrical gyromagnetic waveguide theory on H-tuning characteristics of the main dielectric modes give central frequency and maximum frequency splitting in good agreement with the data. It was theoretically predicted, that noticeably magnetic tuning of magnetodielectric modes´ frequency will take place over all sub-THz frequency range.