Temperature sensitivity of dielectric resonators and dielectric resonator oscillators

Experiments were performed on L-band and S-band dielectric resonators (DRs) and direct-resonator-based oscillators (DROs) to investigate the details of their behavior with variation in temperature. Measurements were performed using commercially available Zr/Sn titanate and barium tetratitanate dielectric resonator materials enclosed in metal cavities. The results indicate that the temperature coefficient of the resonant frequency, τ_f, supplied by vendors of the high-dielectric-constant ceramics, is not sufficient to predict accurately a DRO´s total frequency excursion over a given temperature range. Significant second-order contributions to the frequency versus temperature characteristics were observed, with values ranging from -27 to +20 p.p.b./°C². In addition the cavity material used to enclose the DR can significantly alter its temperature characteristic. Procedures have been developed to aid in the estimation of a DRO´s characteristic temperature sensitivity. They can be used to adjust the DRO design to minimize the total frequency excursion over a desired temperature range