Sumitomo Special Metals Co., Ltd.

Soyoko Ando

Takeshi Shimada

Keisuke Kageyama

A microwave dielectric ceramic composition exhibiting excellent relative permitting (&isin;) and high Qf-value, enabling the temperature coefficient of resonance frequency to be easily adjusted, and being best suited for a filter having cavities made of, e.g., iron or copper exhibiting a large temperature coefficient of resonance frequency. The ceramic is of a BaO&mdash;TiO,&mdash;Nd,O,&mdash;Sm,O,ceramic, type wherein Nd,O,is partly substituted by Bi,O,, Nd,O,is Partly substituted by Ln,O,(where Ln is La, Ce or Pr) and, the above substituted Ln,O,is partly substituted by EU,O,to improve the properties so that &isin; is 82.5 to 92.5, Qf is 6000 to 7300 GHz and &tgr;f is 10-20 ppm/&deg; C. This makes it possible to impart favorable electric characteristics to resonance cavities of various materials and sizes.

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Ibaraki, Japan

Soyoko Ando