Dielectric Ceramic, Dielectric Resonator Utilizing Same, and Method for Manufacturing Dielectric Ceramic

A dielectric ceramic comprising a crystal containing La, Al, Ca and Ti as a main component, the dielectric ceramic containing a molybdenum oxide,

• wherein when the composition formula of the crystal phase is represented by αLa2OX.βAl2O3.γCaO.δTiO2 wherein 3≦X≦4, the molar ratios α, β, γ and δ satisfy the following expressions.
• 0.056≦α≦0.214,
• 0.056≦β≦0.214,
• 0.286≦γ≦0.500,
• 0.286≦δ≦0.460, and
• α+β+γ+δ=1

A method for manufacturing a dielectric ceramic, comprising:

• mixing respective powders of a lanthanum compound, an aluminum compound, a calcium compound, and a titanium compound with a powder of any one of a molybdenum oxide, manganese tungstate, and manganese titanate, thereby producing a mixture,
• applying a pressure to the mixture, thereby forming a green body, and
• sintering the green body,
• wherein in the mixing, the respective powders of the lanthanum compound, the aluminum compound, the calcium compound, and the titanium compound are mixed with the powder of the manganese tungstate or the manganese titanate and the mixture contains the powder of the manganese tungstate or the manganese titanate in an amount of 0.01 to 3% by mass.

A dielectric ceramic comprising a crystal containing La, Al, Ca and Ti as a main component, the dielectric ceramic containing a manganese tungstate or a manganese titanate, wherein when the composition formula of the crystal phase is represented by αLa2OX.βAl2O3.γCaO.δTiO2 wherein 3≦X≦4, the molar ratios α, β, γ and δ satisfy the following expressions.

• 0.056≦α≦0.214,
• 0.056≦β≦0.214,
• 0.286≦γ≦0.500,
• 0.286≦δ≦0.460, and
• α+β+γ+δ=1