US 4,422,012 AGranted

Ladder supported ring bar circuit

AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration

InventorHenry G. Kosmahl

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Abstract

An improved slow wave circuit especially useful in backward wave oscillators includes a slow wave circuit (10) in a waveguide (12) as shown in FIG. 1. The slow wave circuit is comprised of rings 11 disposed between and attached to respective stubs (13,14). The stubs (13,14) are attached to opposing sidewalls of the waveguide (12). To the end that opposed, interacting magnetic fields will be established to provide a very high coupling impedance for the slow wave structure, axially orientated bars (20) are connected between rings in alternate spaces and adjacent to the attachment points of stubs 13. Similarly, axial bars (21) are connected between rings in the spaces which do not include bars (20) and at points adjacent to the attachments of bars (21). FIG. 2 shows the current loops (22,23) available because of the inventive structure. FIG. 3 shows that rings 11 may be half rings of 180.degree. arc. FIG. 4 illustrates that the rings or half rings (11) with stubs (13,14) may be formed of flat metal ribbons.

Claims12

Dependent claims

A slow wave structure for a backward wave oscillator tube, said slow wave structure being disposed in a wave guide and comprising:

a plurality of rings disposed in axial alignment in said waveguide, said rings being coaxial with the longitudinal center of said waveguide;
a first plurality of electrically conducting stubs extending inwardly from one wall of said waveguide, each stub being attached to a respective ring;
a second plurality of electrically conducting stubs extending inwardly from a wall of said waveguide opposite said one wall, each stub being attached to a respective ring;
a first plurality of electrically conductive connecting bars extending axially in alternate spaces between said rings at the points of attachment of said plurality of stubs to respective ones of said rings;
and
a second plurality of electrically conductive connecting bars extending axially between said rings in the spaces not including said first connecting bars and at the points of attachment of each of said second plurality of stubs to a respective ring, whereby currents in said first connecting bars and in said second connecting bars are in opposite directions to establish magnetic fields resulting in a high impedance characteristic for said slow wave structure;
and
a longitudinal ridge member of electrically conducting, non-magnetic material having high thermal conductivity attached to the inside of each of third and fourth walls of said waveguide and a longitudinal spacer of an electrically nonconductive material having high thermal conductivity disposed between and contacting each ridge member and all of said rings to conduct heat away from said rings, stubs and bars.

5 more elements

Dependencies are inferred from the claim text.