Raytheon Company

USA As Represented by Secretary of the Navy

Robert Harper

Cheryl V Liss

Robert M Unger

Joseph L Rousseau

Slow-wave structures are formed by the method of this invention in the form of helical or coupled-cavity structures. A helical waveguide form of slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then totally eroded away to form a slow wave structure having a helical radially-extending portion, or if only partially eroded with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The helix is extended into a rectangular waveguide for coupling the slow-wave structure to the source and to the load. The coupled-cavity forms of waveguide slow-wave structures are formed by machining disks from a solid rod of copper. The disks are supported in their desired positions by an axial retained portion of the rod until the disks are brazed inside a cylindrical shell of copper. After brazing, the axial retained portion is removed in whole or part to form the completed slow-wave structure.

Helical waveguide to rectangular waveguide coupler

Slow-wave structures are formed by the method of this invention in the form of helical or coupled-cavity structures. A helical waveguide form of slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then totally eroded away to form a slow wave structure having a helical radially-extending portion, or if only partially eroded with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The coupled-cavity forms of waveguide slow-wave structures are formed by machining disks from a solid rod of copper. The disks are supported in their desired positions by an axial retained portion of the rod until the disks are brazed inside a cylindrical shell of copper. After brazing, the axial retained portion is removed in whole or part to form the completed slow-wave structure.

Method of manufacture of coupled-cavity waveguide structure for

A waveguide helical slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then partially eroded away to form a slow wave structure having a helical radially-extending portion with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The slow wave structure contains the microwave energy which follows the spiral path of the structure and produces RF voltage across the gap of adjacent portions of the ridges to thereby form a gapped-wall surrounding an axially-extending hole for gap electric field interaction with the axial electron beam of a traveling wave tube of which the slow wave structure is a part.

Method of manufacture of helical waveguide structure for traveling wave

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.

Backward wave suppressor

A slow wave guiding structure such as a helix delay line for electron intction devices of the traveling wave type having diamond heat sink supports for substantial enhancement of power levels of operation is provided. The diamond supported helix structures are maintained in good thermal contact by pressure only in lieu of the diamonds being bonded to metallic members. The invention is applicable to numerous slow wave structures including ladder, ring-bar, meander, as well as interdigital types.

Diamond supported helix assembly and method

A travelling wave tube of the coupled cavity type including a slow wave propagating structure comprised of a linear array of transverse plates axially spaced apart to provide a sequential series of interposed cavities, each of the plates having a cavity coupling aperture radially spaced from an electron beam transmitting aperture and spanned by at least one thermally conductive, dielectric member made of diamond material, which has respective surface areas disposed in thermal contact with opposing side walls of the cavity coupling aperture.

Coupled cavity structure

Diamond heat sink members are now employed to conduct thermal energy from slow wave structures in traveling wave type interaction devices to permit operation at high power levels. The diamond members are bonded to adjacent desired components by a method including heating an intermediate metal alloy of an inactive conductive metal and a small amount of a carbide constituent in a vacuum and the application of pressure. A critical temperature slightly above the melting point of the alloy of between 1000.degree. C and 1100.degree. C is required to wet and bond the alloy material to the diamond and any desired surface.

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Concord, MA, United States of America

Robert Harper