Dielectric ceramic composition containing ZnO-B.sub.2 O.sub.3 -SiO.sub.2 glass, method of preparing the same, and resonator and filter using the dielectric ceramic composition

A method of producing a dielectric resonator including a dielectric ceramic and a conductive layer embedded in the dielectric ceramic, comprising the steps of:

• providing a dielectric ceramic composition which consists essentially of (i) a main ceramic composition containing barium oxide, strontium oxide, calcium oxide, titanium oxide, rare earth oxide and bismuth oxide as major components, which composition is represented by x((1-c-d)BaO.cSrO.dCaO).yTiO.sub.2.z((1-e)RE.sub.2 O.sub.3.eBi.sub.2 O.sub.3), wherein RE represents at least one rare earth metal, 0.10.ltoreq.x.ltoreq.0.20, 0.60.ltoreq.y.ltoreq.0.75, 0.10.ltoreq.z.ltoreq.0.25, x+y+z=1, 0.ltoreq.c.ltoreq.0.40, 0.ltoreq.d.ltoreq.0.20, 0.ltoreq.e.ltoreq.0.30 and 0<c+d, and (ii) a glass composition comprised of ZnO, B.sub.2 O.sub.3 and SiO.sub.2, which is represented by k(wt. %)ZnO.m(wt. %)B.sub.2 O.sub.3.n(wt. %)SiO.sub.2 where 30.ltoreq.k.ltoreq.85, 5.ltoreq.m.ltoreq.50, 2.ltoreq.n.ltoreq.40, k+m+n=100, said glass composition being contained in an amount of at least 0.1 parts by weight, but not more than (18-62.5e) parts by weight (where 0<e.ltoreq.0.2) or not more than 5.5 parts by weight (where 0.2<e.ltoreq.0.3), per 100 parts by weight of said main ceramic composition;
• and
• co-firing said dielectric ceramic composition with a conductive layer, said conductive layer consisting essentially of Ag or of an Ag alloy containing Ag as a major component.