A dielectric ceramic for use in the region of the microwaves.

摘要

A dielectric ceramic for microwave applications is comprised of:X BaO.Y TiO₂.Z {(Sm₂O₃)_1-W1-W2(La₂O₃)_W1(Nd₂O₃)_W2}where X, Y, Z lie in the ranges: 11.0 ≦ X ≦ 22.0; 60.0 ≦ Y ≦ 75.0; and 6.0 ≦ Z ≦ 28.0 (X + Y + Z = 100) expressed in mole %, and 0 W₁ ≦ 0.35; 0 W₂ 1; and 0 (1 - W₁ - W₂) 1; where W₁, W₂ and (1-W₁-W₂) are mole ratios. MnO₂ or Al₂O₃ may also be added.;Alternatively, a dielectric ceramic may comprise:X BaO.Y TiO₂.Z {(Sm₂O₃)_1-W1-W2(La₂O₃)_W1(Nd₂O₃)_W2}.V Bi₂O₃ where X, Y, Z and V lie in the ranges: 11.5 ≦ X ≦ 21.0; 60.0 ≦ Y ≦ 76.0; 6.5 ≦ Z ≦ 26.0; and 0.1 ≦ V ≦ 5.0 (X + Y + Z + V = 100), expressed in mole %, and 0 W₁ 1; 0 W₂ 1; 0 (1 - W₁ - W₂) 1, where W₁, W₂ and (1-W₁-W₂) are mole ratios. MnO₂, CeO₂, PbO, or Al₂O₃ may also be added.;The dielectric ceramic of the invention has a high dielectric constant ε _r and a high unloaded Q (Q_u), and moreover, the temperature coefficient τ _f of the resonant frequency can be varied over a wide range by varying the composition.