PURPOSE: To reduce the variation in microwave characteristics of each cell by a method wherein a silver soldering is performed on the junction part of a lead wire at the metalized layer of the external connection terminal mounting base, an almost T-shaped external connection terminal is installed, and the length of wire connection is reduced and made uniform.

CONSTITUTION: Ni and Au are plated on a copper substrate 2, and the ceramic external connection terminal mounting bases 3a and 3b are arranged and fixed in such a manner that they pinch a narrow-stripped protrusion 2c. An external connection terminal 8 is a T-shaped Ni-Au plated copper plate consisting of terminal lead-out parts 8a and 8b, which is orthogonally intersecting with the lead wire junction parts 8c and 8d, having the measurements of l×w which is almost same as that of the metalized layer 5a located on the surface of the mounting bases 3a and 3b. A silver soldering is performed on the lower surface of the lead wire connecting parts 8c and 8d, the metalized layer 4a and the terminal lead-out parts 8a and 8b. When performing the above soldering work, silver solder oozes out into a part of the metalized layer 4b, but as the metalized layer 4b is completely covered by the lead wire junction parts 8c and 8d, the length of the wire connection 6 with the element 1 can be made uniform and reduced, thereby enabling to make even the irregularity of the microwave characteristics of each cell.