High frequency investigation on nonradiative single-mode dielectric resonators

A high frequency investigation of the recently proposed nonradiative single-mode dielectric resonators is presented. In particular, the TE011 mode of high density polyethylene and single crystal quartz discs resonating around 190 GHz has been experimentally characterized by means of a simple setup. The obtained unloaded merit factor, 1400 for polyethylene and 2480 for single crystal quartz, leads to a magnetic field conversion factor of 15 G/W1/2 and 49 G/W1/2, respectively. In the latter case, the obtained figure represents the state-of-the-art among the room temperature conversion efficiencies. The close agreement with the theoretical predictions demonstrates that the performances of the proposed resonators are only limited by intrinsic factors, as finite conductivity of metallic mirrors and dielectric losses of the employed materials; ideal performances are then expected in suitably realized nonradiative resonators, also in the high frequency regime.