| 摘要 |
PROBLEM TO BE SOLVED: To provide a band-pass filter capable of suppressing higher order spurious modes while keeping a pass band unchanged. SOLUTION: The band-pass filter comprises a plurality of partition walls 12, a body 11, a frequency adjusting screw 14, a coupling degree adjusting screw 13, at least one pillar-shaped section 16, and a cover 15. The partition walls 12 contain a rectangular waveguide in the inside thereof, and extend from one inner wall to constitute asymmetrical inductive windows. The body 11 is formed unitedly with the partition walls 12, and has an open surface facing the inner wall. The frequency adjusting screw 14 and the coupling degree adjusting screw 13 are arranged at a position separated from the partition walls 12, and adjust a propagation frequency and a degree of coupling of the waveguide according to the length projected into the inductive windows. The at least one pillar-shaped section 16 is provided at the the inductive windows and extended in parallel in relation to the inner wall. The cover 15 closes the open surface of the body 11 and does not contact with the at least one pillar-shaped section 16. Since the cross section of the pillar-shaped unit 16 is made substantially circular, the body 11 can be easily fit in by press-fitting. Thus, the manufacturing of a band pass filter becomes easy. COPYRIGHT: (C)2005,JPO&NCIPI
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