PURPOSE: To make the electric characteristic stable by the method wherein the iris plate is not deformed even when the temperature of the iris plate is changed.
CONSTITUTION: In a coupling cavity filter comprising plural cavity sections 1, 2 and an iris plate 5a forming a cavity resonator are made of different kinds of metals, a thin plate 15 formed with a thin plate having a coupling hole opening 14 and a thick section 16 formed to have an inner diameter a little larger than an outer diameter of the cavity sections 1, 2 in a heated state to an outer circumferential part of the thin plate 15 form the iris plate 5a and the iris plate 5a is inserted between the cavity sections 1, 2 and they are fixed and connected so that the inner circumference of the thick part 16 is in press contact with the outer circumference of the cavity sections 1, 2 while the iris plate 5a and the cavity sections 1, 2 are heated.
NOMOTO TOSHIHIRO
YAZAWA NORIHIKO
