CONTRIBUTION OF DIELECTRIC-CONSTANT TO CHANGE IN TEMPERATURE-COEFFICIENT OF RESONANT-FREQUENCY IN (BA1-XSRX)(MG1/3TA2/3)O3 COMPOUNDS

Dielectric resonator materials with the formula (Ba1-xSrx)(Mg1/3Ta2/3)O3 have been studied in order to clarify the factors controlling the resonant frequency as a function of temperature. Dielectric constant and thermal expansion are calculated from the resonant frequency measured by the dielectric resonator method and the capacitance obtained at 10 kHz. The results show that the temperature dependence of the resonant frequency originates mainly from the change in the dielectric constant with temperature. The dielectric constant exhibits a maximum at some critical temperature, which varies with increasing strontium content in the oxides.