PURPOSE: To reduce the number of parts and also to reduce the size of the titled filter by setting up I/O coupling capacitance on a dielectric base plate and inter- stage coupling capacitnace to inter-electrode capacitance obtained through a dielectric body and fitting the dielectric base plate approximately vertically to the opening end surface of resonators.
CONSTITUTION: I/O capacitance is formed at an ovelapped part between an I/O capacitance forming electrode 12 formed on the dielectric base plate 2 and the other inter-stage coupling electrode 11, and inter-stage coupling is formed by series capacitance at an overlapped part between a series capacitance forming electrode 13 and two electrodes 11. The base plate 2 is fitted vertically to the leading end part of a central conductor 6 of a resonator in each stage and fixed by soldering or the like so that the electrode 11 is connected to the conductor 6 through a projected part 14. A frequency adjusting screw 3 fitted so as to be opposed to the electrode 11 varies the capacitance to adjust the frequency. Thus, the dielectric base plate is fixed, so that the number of parts can be reduced and the size of the filter can be also reduced.
MAKIMOTO MITSUO
YAMASHITA SADAHIKO
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