Compact delay line formed of concentrically stacked, helically grooved, cylindrical channel-line structure

A delay line device comprising:

• a first, generally cylindrical body element having a longitudinal axis and an outer, generally cylindrical surface in which a helical groove is formed, said helical groove having an electrically conductive surface;
• a plurality of generally cylindrical hollow body elements of successively increasing diameters, wherein respective ones of said body elements are concentrically stacked about the longitudinal axis of said first body element, and wherein each of said hollow body elements has an electrically conductive, generally cylindrical bore and an outer, generally cylindrical surface in which a helical groove is formed;
• which helical groove has an electrically conductive surface;
• an outer body element having a generally cylindrical bore into which bore said first body element and said plurality of generally cylindrical hollow body elements are inserted, so that said outer body element surrounds said plurality of generally cylindrical hollow body elements and said first body element that are stacked together concentrically about said longitudinal axis, the generally cylindrical bore of said outer body element having an electrically conductive surface;
• and
• respective lengths of conductor which are supported within each of respective ones of said helical grooves in a manner so as to be electrically insulated from the electrically conductive surfaces of respective ones of said helical grooves and the bores of adjacent body elements.

A method of forming a delay line device comprising the steps of:

• (a) forming a helical groove in an outer surface of an electrically conductive, cylindrical body element having a longitudinal axis;
• (b) forming a helical groove in an outer surface of each of a plurality of electrically conductive, generally cylindrical hollow body elements of successively increasing diameters, which are sized so that respective ones of said body elements are concentrically stacked about the longitudinal axis of said electrically conductive, cylindrical body element;
• (c) placing respective lengths of insulated conductor wire within each of respective ones of said helical grooves in a manner so as to be electrically insulated from the electrically conductive surfaces of respective ones of said helical grooves of adjacent body elements;
• (d) placing said plurality of electrically conductive, generally cylindrical body elements and said first body element within a cylindrical bore and an outer body element, which bore is sized so as to accommodate the insertion of said first body element and a concentrically stacked plurality of said generally cylindrical hollow body elements therein, so that said outer body elements surrounds said plurality of generally cylindrical hollow body elements and said first body element that are stacked together concentrically about said longitudinal axis;
• and
• (e) providing electrical connections to said conductor wire.