US Patent 11362405 Filter

A filter includes a waveguide formed in a dielectric surrounded by a conductor wall. The conductor wall includes at least one control wall protruding toward an inner side of the waveguide. The at least one control wall includes an end portion in a protruding direction of the at least one control wall and a central portion in the protruding direction. The end portion includes a wall portion of which wall thickness is different from the central portion.