Abstract: A band-stop filter comprises a plurality of resonator units each comprised of an end-shorted coaxial resonator and a variable condenser connected in series therewith, a printed circuit board combining said resonator units in a multistage having thru-holes adjacent a bushing which isolates the inner conductor of the end-shorted coaxial resonator from the printed circuit board. A thru-hole conductor is provided in the thru-hole, and an adjusting screw having a radius is a little larger than the thru-hole. The adjusting screw can have both the proper torque and the electrical connection. The inner conductor surface of the resonator operates electrically as a stator and the adjusting screw operates as a rotor.

Abstract: A branching filter for separating or combining two different frequencies without interference in radio communication equipment etc. One or both of two filter blocks for separating or combining two signal waves whose central frequency differ from each other are constructed from a dielectric bandpass filter which allows the desired wave of a block to pass and a SAW band stop filter being connected in series with said filter which allows the desired wave of a block to pass and stops passing of the desired wave of another block.