| 摘要 |
A traveling wave tube (TWT) has a slow wave structure in the form of a helix for amplifying the forward electromagnetic wave. The TWT is provided with an outer slow wave assembly for attenuating a backward wave to provide stability to the TWT. A set of ceramic rods are uniformly spaced circumferentially around the helix for supporting the outer slow wave assembly which is formed by an electrically conducting wire wound around the supporting rods. The wire is wound in a helical fashion with individual turns of the helix being spaced apart to form the outer slow wave structure. An electrically conducting cylinder surrounds the outer slow wave structure and is in contact therewith only at the sites of the rods. Dielectric slabs, having a slow wave structure such as a meander line disposed thereon, are inserted periodically around the outer slow wave structure in spaces between the winding and the cylinder. The spacing between the turns of the winding is selected for coupling a backward wave of a specific frequency to the dielectric slabs for attenuation of the backward wave.
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