| 摘要 |
PURPOSE:To facilitate the working, by providing >=2 metallic posts, which have a length of about lambdah (guide wavelength of higher harmoinics)/4, at intervals of about lambdag (guide wavelength of fundamental waves)/4 on the upper face of a rectangular waveguide provided with a narrow part to obtain a simple constitution where a specific higher harmonic of a used frequency is stopped. CONSTITUTION:A narrow part 24, where a height (b) in the direction of the shorter side is reduced to such height A that the higher mode is not generated in a specific higher harmonic, is provided in a part of a rectangular waveguide 21. Step parts having a length D of about lambdag/4 are provided between aperture parts 22 and the narrow part 24 to attain the matching to a standard waveguide in aperture parts 22. Metallic posts 25A and 25B having a length of about lambdah/4 are provided at the interval of about lambdag/4 on the upper face of the narrow part 24. Metallic posts 25A and 25B function as a short-circuiting circuit for higher harmonics, and the higher mode is not generated in the narrow part 24, and therefore, only fundamental waves are allowed to pass through. Since metallic posts 25A and 25B are provided lambdag/4 apart from each other, susceptances are cancelled to perform the impedance matching. |
