Traveling wave tube with periodic permanent magnet focused multiple electron beams

摘要

A coupled cavity traveling wave tube has periodic permanent magnet (PPM) RF cavity structures, each of which has a plurality of permanent magnets placed substantially equidistant from a central axis, and which are outside the extent of a plurality of electron beam tunnels arranged substantially equidistant from the central axis and within the extents of the plurality of permanent magnets. Each coupled cavity RF structure is formed by adjacent ferrous polepieces and a cylindrical wall which is beyond the extent of one or more coupling apertures which couple RF energy from one coupled cavity structure to an adjacent RF cavity.