Microwave dielectric properties of BaO-TiO/sub 2/-WO/sub 3/ ceramics sintered with glasses

Abstract

The microwave dielectric properties and the sintering behavior of commercial BaO-TiO/sub 2/-WO/sub 3/ dielectrics, N-35, with addition of various glasses; (1) simple glass formers, (2) ZnO-B/sub 2/O/sub 3/ based, (3) B/sub 2/O/sub 3/-SiO/sub 2/ based and (4) Al/sub 2/O/sub 3/-SiO/sub 2/ based glasses were studied. The Q of N-35 sintered with a ZnO-B/sub 2/O/sub 3/ glass system showed a sudden drop in the sintering temperature to around 1000/spl deg/C. Results of XRD, thermal analysis and scanning electron microscopy suggest that the chemical reaction between N-35 and the glass had a larger effect on Q than density. A 5wt% addition of B/sub 2/O/sub 3/ to N-35, when sintered at 1200/spl deg/C, had the best dielectric properties, Q=8300 and K=34.1 at 8.5 GHz, among the glasses Q, K and density increased with sintering temperature from 1000 to 1200/spl deg/C. The effects of the amount of glass added and the mixing method on the density and the dielectric properties will be discussed.