| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To effectively suppress second-order harmonic with a simple structure, without having a structure projecting into a waveguide. <P>SOLUTION: A harmonic cutoff filter includes a recessed part 301 on a surface of one inner wall surface 201 on a cross-sectionally long side within a cross-sectionally rectangular waveguide 201 of a waveguide 11, and a recessed part 401 on a surface of the other inner wall surface 201a. The recessed parts 301, 401 have the same shape, and the length L thereof in the waveguide axis direction is generally one digit or more smaller than an in-waveguide wavelength of a fundamental wave propagating through the waveguide. The width of the recessed parts 301, 401 in the cross-sectionally longitudinal direction is≤1/2 of the in-waveguide wavelength of the fundamental wave. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
