Back to results
US 4,812,854 AGranted
Mesh-configured rf antenna formed of knit graphite fibers
AssigneeHarris Corporation
InventorsBobby J. Boan, Martin Schwam
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeHarris Corporation
InventorsBobby J. Boan, Martin Schwam
Estimating the term…
An antenna reflector material for electromagnetic waves is comprised of knitted strands of fine diameter graphite filaments, which have been individually coated with a stress absorbing layer (e.g. a thin metallic or dielectric cladding). Because of the stress absorbing coating, the graphite fibers, which, by themselves, are inherently brittle and unable to tolerate substantial changes to their bend radius profiles, are able to be successfully knitted into a tricot mesh configuration and thereby yield an antenna surface material that possesses a near-zero coefficient of thermal expansion and a sufficiently low in-plane mechanical stiffness. After the tricot knit graphite mesh material has been formed, the cladding layer may be removed (e.g. by heat or chemically dissolved), without affecting the mechanical properties of the graphite strands of the tricot knit. The intended displacement capability of the loops of graphite strands within the knit mesh structure are retained, so that thermal inputs do not alter the performance characteristics of the graphite mesh antenna.
An antenna for electromagnetic waves comprising a conductive open mesh formed of strands of filaments of carbon-containing material, each strand being formed of a bundle of plural filaments of carbon-containing material in which relative movement among filaments of the bundle is afforded, with each opening of said mesh being defined by multiple loops of said strands, wherein at least one of said loops is formed by the same strand folded back upon itself, the mesh being configured such that relative displacement between loops at different portions of the mesh is permitted, thereby enabling the loops of said strands of filaments of carbon-containing material at relatively different portions of the mesh to pass by one another and enter open regions of the mesh, so as to be effectively mechanically displaceable with respect to one another in the contour of the mesh in response to changes in environmental conditions, whereby the effective contour of the antenna formed by the mesh is retained.
An antenna for electromagnetic waves comprising conductive strands made up of a plurality of graphite filaments formed as an open knit mesh, each strand being formed of a bundle of plural filaments of carbon-containing material in which relative movement among filaments of the bundle is afforded, with each opening of said mesh being defined by multiple loops of said strands, wherein at least one of said loops is formed by the same strand folded back upon itself, the mesh being configured such that relative displacement between loops at different portions of the mesh is permitted, thereby enabling the loops of graphite strands at relatively different portions of the mesh to pass by one another and enter open regions of the mesh, so as to be effectively mechanically displaceable with respect to one another in the contour of the mesh in response to changes in environmental conditions, whereby the effective contour of the antenna formed by the mesh is retained.
A method of forming an electromagnetic wave reflective material for use as an antenna comprising the steps of:
Dependencies are inferred from the claim text.