Dielectric ceramic composition

Abstract

An alumina based dielectric ceramic composition comprising a base material and an additive material. The base material is represented by the general formula (x) Al,O,+(y) TiO,wherein x and y are percentages of the total weight of the base material, and x is in the range of about 60 to about 96, more preferably about 94 to about 96, and y is in the range of about 4 to about 40, more preferably about 4 to about 6. In one embodiment the additive material comprises Nb,O,. In a second embodiment the additive material further comprises at least one additional component selected from the group consisting of BaCO,, SnO,, Mn,O,, MnCO,, Mg(OH),, and Y,O,. The composition requires a relatively lower peak soak temperature (as compared to conventional alumina ceramics) of about 1320 to about 1400° C., more optimally about 1350 to about 1370° C., and is particularly suited for use in high frequency applications. The resulting sintered compositions exhibit a low dielectric constant (about 10 to about 12, more preferably about 11.5 to about 12); a high Q factor (about 10,000 to about 55,000, more preferably about 30,000 to about 50,000); a low temperature coefficient (about −30 to about 30 ppm/° C., more preferably about −3 to about 1); and a high percent fired density (about 95 to about 100, more preferably about 98.33 to about 99.20).