| 摘要 |
<p>A first circular waveguide or an elliptical waveguide has an inner circumferential surface tapered such that its inside dimension is gradually reduced continuously toward an end thereof. The elliptical waveguide comprises an antenna waveguide connected to an antenna device. Another circular waveguide has an end joined to the end of the first circular waveguide or the elliptical waveguide. Both waveguides have different inside dimensions at the joined ends. A hermetic seal is sandwiched between the joined ends of both the waveguides. The tapered inner circumferential surface is effective to cancel out a susceptance produced by the hermetic seal. The first waveguide with the tapered inner circumferential surface can easily be manufactured by die casting. <IMAGE></p> |
