| abstract |
Multiphase metal oxide ceramic compositions suitable for use in microwave band filters for telecommunications equipment are composites of metal oxides which comprise, on an elemental weight basis, about 42 to about 50% aluminum, about 2.5 to about 6% titanium, about 0.05 to about 1.5% niobium, about 0.04 to about 1% barium, about 0.03 to about 0.7% zirconium, about 0.01 to about 0.3% manganese, up to about 2.5% nickel, and up to about 4% zinc, wherein the aluminum and titanium are present in the composition, as metal oxides, in an elemental weight ratio of Al:Ti in the range of about 8:1 to about 17:1. The ceramic compositions have a resonant frequency, f, in the range of about 2.4 to about 10 GHz, a quality factor, Q, of at least about 4000, a dielectric constant, K, in the range of about 10 to about 15, and a temperature coefficient of resonant frequency, T f in the range of about −20 ppm to about +20 ppm. Metal oxide powder compositions useful for preparing the dielectric ceramic compositions and a method of making the ceramic compositions are also described. |