Microwave characterisation of BaCe2Ti5O15 and Ba5Nb4O15 ceramic dielectric resonators using whispering gallery mode method

A microwave dielectric ceramic resonators based on BaCe2Ti5015 and Ba5Nb4O15 have been prepared by conventional solid state ceramic route. The dielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) technique was employed for the accurate determination of the dielectric properties in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have quality factors (Q×F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coefficient of resonant frequency (τf) of BaCe2Ti5O15 and Ba5Nb4O15 have been measured accurately using different resonant modes and are +41 and +78 ppm/K, respectively.