An alternative method for the measurement of the microwave temperature coefficient of resonant frequency (τ f )

In this paper an alternative method for the measurement of the temperature coefficient of resonant frequency (τf), is presented. The traditional method (based on the Courtney method) present some limitations of measuring the values of τf, for samples with high dielectric loss due to their inability to observe clearly the TE011 mode. The alternative experimental setup, to measure the τf value, is based on the variation of the temperature of the dominant mode of a dielectric resonator antenna. The method is quite compatible with the measurement of τf, based on the Courtney method. It presents the advantage that it is less sensitive to the sample loss. In the studied samples, with loss higher than 10−2, the τf were obtained. Samples of known τf were measured in both methods, using the configuration proposed by Courtney and the present study. The alumina (Al2O3) and calcium titanate (CaTiO3) were selected because they have well known values of τf and have low dielectric losses, the bismuth niobate and titanium (Bi3NbTiO9) was chosen because it is not possible to measure its τf by the traditional method due to its high dielectric loss. The obtained results, by measuring, the τf value of CaTiO3 and Al2O3, in this proposed method, present excellent agreement when compared to the traditional Courtney, transmission method. It was also very efficient for measurements of the τf value, of high dielectric loss materials (>10−2), as for the bismuth and titanium niobate (Bi3NbTiO9). The analysis of the temperature coefficient of resonant frequency (τf) in dielectric resonators is an important property for the development of electronic devices. This is because the τf is a fundamental parameter, for the production of new components like filters, oscillators and antennas, with high thermal stability.