Ring-bar slow wave structure and fabrication method

A method of fabricating a tubular ring bar slow wave structure, said structure comprising a tubular ring-bar slow wave structure which in turn comprising a plurality of axially spaced, coaxially aligned, generally parallel metallic rings connected by a plurality of generally axially parallel, alternately spaced metallic bars, said method comprising the steps of:

• mounting said tubular ring-bar slow wave structure around the periphery of a cylindrical mandrel;
• mounting a plurality of tubular, flexible mask rings around said ring-bar structure.
• said plurality of mask rings being snappably transported by a spreader strip, and
• each of said mask rings being aligned for mounting on adjacent metallic rings,
• such that a central peripheral surface of each metallic ring less than the entire width of each ring is exposed;
• removing said spreader strip to allow said plurality of mask rings to envelop said ring-bar stucture, exposing said central peripheral surface of each said metallic ring;
• depositing a dielectric material over both said exposed central peripheral surface of said metallic rings and said plurality of mask rings;
• grinding said dielectric material to a predetermined radial dimension which is greater than the radial dimension of said plurality of mask rings;
• removing said mandrel;
• and
• removing said plurality of mask rings by chemical etching,
• whereby said ring-bar slow wave structure comprises a plurality of axially spaced, coaxially aligned, generally parallel dielectric support rings, each of which being positioned atop a corresponding metallic ring with a width narrower than said width of each of said metallic ring and whereby an outer dielectric material support envelope connects said plurality of dielectric support rings.

A method of fabricating a tubular ring-bar slow wave structure, said structure comprising a plurality of axially spaced, coaxially aligned, generally parallel metallic rings connected by a plurality of generally axially parallel, alternately spaced metallic bars, said method comprising the steps of:

• mounting said tubular ring-bar slow wave structure around the periphery of a cylindrical mandrel;
• mounting a plurality of tubular, flexible alternately directioned mask rings around said ring-bar structure,
• said alternately directioned masks rings being snappably transported by two spreader strips, and
• each of said mask rings being aligned for mounting on adjacent metallic rings,
• such that a central peripheral surface of both said metallic ring and said metallic bar less than the entire width of said metallic ring and said metallic bar is exposed;
• removing said spreader strips to allow said plurality of mask rings to envelop said ring-bar structure, exposing said central peripheral surface of each said metallic ring and each said metallic bar;
• depositing a dielectric material over both said exposed central peripheral surfaces of said metallic rings and bars and said plurality of mask rings;
• grinding said dielectric material to a predetermined radial dimension;
• removing said mandrel;
• and
• removing said plurality of mask rings by chemical etching,
• whereby said ring-bar slow wave structure comprises a plurality of axially spaced, coaxially aligned, generally parallel dielectric support rings and generally axially parallel, alternatively spaced dielectric support vanes, each of which being positioned atop a corresponding metallic ring and metallic bar with a width narrower than said width of each said metallic ring and each said metallic bar.