The frequency stability of the DRO over temperature is selected by taking into account the total circuit. In other words, the temperature characteristics of the supporting structure, the epoxy with which the DR is attached, the RF device, and the circuit housing must be accounted for during selection of the dielectric resonator material and temperature coefficient.
A frequency stability of 3 parts per million per degree Centigrade (3 ppm/C°) for a DRO operating around 10 GHz is typically achievable. This corresponds to a frequency shift of 30 kHz per Centigrade degree shift.
Besides temperature coefficient, the DR is selected for its size and dielectric constant. Figure 3 shows that the size of the DR (the thickness to diameter ratio of a DR is generally kept to 0.4 for the widest mode separation) is inversely proportional to the frequency of the DRO for the same dielectric material.