Coupler for static focussed travelling wave tube - has rib connected to slow wave helix and guide of similar dimension to focussing magnet

摘要

The output waveguide (17) contains at least one rib (16) which is joined at one end to the slow wave helix (1) and coupled at the other end (12) to the output. The thickness of the guide along the axis of the tube is constrained to be no more than a focussing magnet (5). The guide is rectangular with the rib along one wide side, perpendicular to it along the centre line. The depth and thickness of the rib is variable. The output of the rib is extended to form a probe (10) covered by a brased insulating sealing dome (11) inside a standard waveguide (12) or joined to a standard ribbed waveguide or the inner conductor of a coaxial line with a sealing window. The guide is contained within the dimensions of one of the focussing ring magnets and therefore perturbs the field no more than the coaxial output.