WAVEGUIDE BAND-PASS FILTER

PROBLEM TO BE SOLVED: To provide a waveguide band-pass filter that is easy to construct/manufacture even when a signal in a high frequency band is allowed to pass through the filter.SOLUTION: A resonance part length L1 that is a length of a resonance part 2 in a propagation direction is set based on the resonance part length L1 in a TE10n (n is an integer equal to or greater than 2) mode, and a resonance part width L2 that is a length of the resonance part 2 in a direction orthogonal to the propagation direction is set wider than the resonance part width L2 in a TE101 mode. Also, suppression parts 2a are provided which inwardly protrude from both side faces 2b of the resonance part 2 along the propagation direction and suppress propagation of a signal in a higher-order mode.