| 摘要 |
PROBLEM TO BE SOLVED: To effectively suppress leakage of electromagnetic waves from a gap between waveguides required for resonance frequency variation of a filter irrespective of relative positions of the waveguides.SOLUTION: In a millimeter wave band filter, a waveguide for propagating electromagnetic waves of a millimeter wave band in a TE10 mode is formed of: a first waveguide tube 21; and a second waveguide tube 22 which has an inner diameter slightly larger than an outer diameter on one end side of the first waveguide tube 21, and is connected to the first waveguide tube 21 in a relatively movable state in a waveguide direction in a state of accepting the one end side of the first waveguide tube 21 inside, one 30A of radio wave half mirrors is fixed so as to block one end side opening of the first waveguide tube 21, and the other 30B is fixed to the inside of the second waveguide tube 22, a groove 50 for suppressing leakage of electromagnetic waves from a gap between an outer peripheral wall of the first waveguide tube 21 and an inner peripheral wall of the second waveguide tube 22 is formed at predetermined depth inward at an outer peripheral part of the radio wave half mirror 30A fixed to the one end side of the first waveguide tube 21. |
