Traveling-wave tube with improved periodic permanent magnet focusing arrangement integrated with coupled cavity slow-wave structure

Claim 1

A device for focusing a stream of electrons and constraining it to flow along a predetermined path and for providing a series of electromagnetically intercoupled interaction cavities arranged sequentially along said predetermined path in electromagnetic interacting relationship with said stream of electrons, comprising: a plurality of substantially annular permanent magnets magnetized axially and coaxially disposed about said predetermined path with like poles of adjacent magnets confronting one another; a plurality of substantially annular ferromagnetic pole pieces respectively coaxially interposed between and abutting adjacent ones of said magnets and extending radially inwardly of said magnets to a radial distance substantially outwardly of said predetermined path, each of said pole pieces defining a cylindrical aperture therethrough having a circumferential surface which constitutes the lateral wall of one of said interaction cavities; first, second and third substantially annular plate-like members of electrically conductive non-magnetic material disposed coaxially about said predetermined path and radially within each of said magnets, said first and third plate-like members abutting and being hermetically bonded to the respective pole pieces abutting opposite ends of the said magnet, said second plate-like member being disposed axially substantially midway along the length of the said magnet; first and second substantially annular spacer members of electrically conductive non-magnetic material disposed coaxially about said predetermined path and radially within each of said magnets, said first spacer member being disposed axially between and abutting said first and second plate-like members and being hermetically bonded thereto, said second spacer member being disposed axially between and abutting said second and third plate-like members and being hermetically bonded thereto, each of said spacer members defining a cylindrical aperture therethrough having a circumferential surface which constitutes the lateral wall of one of said interaction cavities; each of said plate-like members extending radially inwardly of said pole pieces and spacer members to the vicinity of said predetermined path, the broad surfaces of said plate-like members consituting end walls of said interaction cavities, said plate-like members defining aligned apertures in their respective central regions to provide a passage for said stream of electrons, and each said plate-like member further defining a coupling hole therethrough in a region radially outwardly of its central region for intercoupling adjacent interaction cavities.

Claim 2

A device for focusing a stream of electrons and constraining it to flow along a predetermined path and for providing a series of electromagnetically intercoupled interaction cavities arranged sequentially along said predetermined path in electromagnetic interacting relationship with said stream of electrons, comprising: a plurality of substantially annular permanent magnets magnetized axially and coaxially disposed about said predetermined path with like poles of adjacent magnets confronting one another; a plurality of substantially annular ferromagnetic pole pieces respectively coaxially interposed between and abutting adjacent ones of said magnets and extending radially inwardly of said magnets to a radial distance substantially outwardly of said predetermined path, each of said pole pieces defining a cylindrical aperture therethrough having a circumferential surface which constitutes the lateral wall of one of said interaction cavities; first, second and third substantially annular plate-like members of electrically conductive non-magnetic material disposed coaxially about said predetermined path and radially within each of said magnets, said first and third plate-like members abutting and being hermetically bonded to the respective pole pieces abutting opposite ends of the said magnet, said second plate-like member being disposed axially substantially midway along the length of the said magnet; first and second substantially annular spacer members of electrically conductive non-magnetic material disposed coaxially about said predetermined path and radially within each of said magnets, said first spacer member being disposed axially between and abutting said first and second plate-like members and being hermetically bonded thereto, said second spacer member being disposed axially between and abutting said second and third plate-like members and being hermetically bonded thereto, each of said spacer members defining a cylindrical aperture therethrough having a circumferential surface which constitutes the lateral wall of one of said interaction cavities; each of said plate-like members extending radially inwardly of said pole pieces and spacer members to the vicinity of said predetermined path, the broad surfaces of said plate-like members consituting end walls of said interaction cavities, said plate-like members defining aligned apertures in their respective central regions to provide a passage for said stream of electrons, and each said plate-like member further defining a coupling hole therethrough in a region radially outwardly of its central region for intercoupling adjacent interaction cavities.