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

A microwave dielectric ceramic resonators based on BaCe(2)Ti(5)0(15) and Ba 5Nb4O15 have been prepared by conventional solid state ceramic route. The d ielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe 2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) tech nique was employed for the accurate determination of the dielectric propert ies in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have qu ality factors (Q X F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coeffici ent of resonant frequency (tau(f)) of BaCe2Ti5O15 and Ba5Nb4O15 have been m easured accurately using different resonant modes and are +41 and +78 ppm/K , respectively. (C) 2000 Elsevier Science B.V. All rights reserved.