Waveguide bandpass filter having a ladder shape metal plate and which is tunable using a rotatable dielectric plate

Abstract

Provided is a bandpass filter (), including: a filter casing () defining a rectangular waveguide () having a narrow plane (a) and a broad plane (b); a metal plate () having a ladder shape and being arranged in a sandwiched manner inside the filter casing () at a center of the broad plane (b) so as to be parallel to the narrow plane (a); a dielectric plate () positioned in a vicinity of the metal plate (); a support rod () extending in parallel to a longitudinal direction of the rectangular waveguide (), the support rod () being rotatably supported on the filter casing () and configured to support the dielectric plate (); and a first gear () fixed at a tip of the support rod (). The dielectric plate () is rotated along with rotation of the first gear (), to thereby adjust a bandpass frequency.