| 摘要 |
PURPOSE: To enable a basic mode microwave transmission in a wide range and with low signal attenuation by shifting the disposition of the higher part and the lower part of a corrugation at the side opposite to a waveguide and maximizing a distance between corrugations directly opposite to each other. CONSTITUTION: The waveguide 20 has no sharp corner and is formed in a sectional form having a line in a prescribed dumbbell form, and that dumbbell form has ridges 22 and 24 at opposite positions each of which forms a cross section in a bell shape extending to the projected end part 26/28 of the cross section of the waveguide formed around a major axis, respectively. Then, the higher part and the lower part of a corrugation on one of the opposite wall surface of the waveguide 20 are include a higher part and a lower part which are disposed so as to be shifted to the higher part and the lower part of a corresponding corrugation on this opposite wall surface of the waveguide, so that a gap between the opposite wall surfaces of the waveguide increases. Thus, a basic mode operation over an extended frequency bandwidth with the lower signal attenuation is enabled. |
