Production and characterization of ceramics for microwave applications

New research and developments on microwave communication result in a rising demand for dielectric resonators. Dielectric oxide ceramics are used as filters, oscillators in a variety of applications from mobile phones to global positioning systems. It has also played an important role in the microwave wireless communications industry by reducing the size and cost of the antenna components. In this study, dielectric ceramic compositions (i.e., CeO2-Glass (5 wt.%, Al2O3-SiO2-CaO based), SrNb2O6, Ba2Ti9O20, 0.68CaTiO3-0.32Ca(Zn1/3Nb2/3)O3 and Ba6-3x(Nd1 yBiy)8+2xTi18O54 x=2/3 and y=0.07) with various dielectric constants between 20 and 100 were synthesized by solid state method and successfully fabricated by dry pressing. The ceramics were then characterized for densification, phase formation, microstructure evolution, dielectric and microwave properties. XRD proved the desired phase formation for all compositions. All sintered samples had a relative density ≥97.35%. Dielectric constants (losses) at 5 MHz at the best sintering conditions for each composition were 21.36 (0.0040) at 1150˚C for CeO2-Glass, 28.87 (0.0047) at 1275˚C for SrNb2O6, 39.55 (0.0034) at 1300˚C for Ba2Ti9O20, 89.98 (0.0035) at 1400˚C for 0.68CaTiO3-0.32Ca(Zn1/3Nb2/3)O3 and 92.04 (0.0053) at 1320˚C for Ba6-3x(Nd1-yBiy)8+2xTi18O54 x=2/3 y=0.07. The CeO2-Glass (5 wt.%) composition was studied for the first time in literature.