| 摘要 |
PROBLEM TO BE SOLVED: To provide a millimeter wave band filter capable of varying a resonant frequency over a wide band without the deterioration of resonance characteristics caused by electromagnetic wave leakage.SOLUTION: In a millimeter wave band filter 20, radio wave half mirrors 30A and 30B are provided, respectively, in a waveguide 23 of a first waveguide 22 for propagating electromagnetic waves within a predetermined frequency range of a millimeter wave band under the TE10 mode, and a waveguide 25 of a second waveguide 24 that is connected while interpolating one end side to the first waveguide 22. An interval between the radio wave half mirrors 30A and 30B is varied by relatively moving the waveguides 22 and 24, and the resonant frequency of a resonator formed between the mirrors is varied, thereby selectively passing the resonant frequency component thereof. On an outer wall of the second waveguide 24 opposite to an inner wall of the first waveguide 22, a groove 90 is provided of which a length (p) in a length direction of the waveguide corresponds to a 1/4 wavelength of electromagnetic waves subjected to leakage prevention, thereby preventing electromagnetic wave leakage from the gap between the first waveguide 22 and the second waveguide 24. |
