| 摘要 |
PURPOSE:To put resonance due to a wave in high-order mode out of an in-use band almost without exerting influence upon the passing characteristics of a basic mode wave by making bosses uneven in height. CONSTITUTION:Bosses 3 which are high enough for necessary filter characteristics are provided near the center of a rectangular waveguide 1 and bosses 4 which differ in height from the bosses 3 are provided near narrow-width surfaces of the rectangular wave-guide 1. The electric field of the basic mode wave is small at the bosses 4, which, therefore, exert almost no influence upon the passing characteristics of the filter. The electric field of the high-order mode wave, however, is larger at the bosses 4 than the electric field of the basis mode wave, so the rate of wavelength shortening increases and the resonance frequency of the high-order mode wave varies greatly. Therefore, unnecessary resonance by the high-order mode wave is put out of the in-use resonance. |
