Clutter and multipath suppressing sidelobe canceller antenna system
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorBernard L. Lewis
Life of this patent
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Abstract
An improved antenna and interference-cancelling system for improving signal ampling, particularly in side-lobe canceller system operating in a multiple-interference-source environment. An antenna is constructed as a circularly symmetric lens having loosely coupled feed elements disposed around the periphery of the lens. Each feed element acts as a high-azimuth-gain antenna which permits signal reception from all directions. The lens, when connected to couple the receiving feed elements to a side-lobe canceller, permits the canceller to discriminate against clutter and scattered signals and resolve interference sources in angle so that all canceller loops do not receive signals from all other interference sources, while still providing interference samples from all directions.
Claims16
An apparatus for processing signals from a multiple interference source environment comprising:
- a single, circular, symmetric lens member formed from a pair of substantially identically shaped, circular, electrically conductive plates the peripheries of which are flared and from a lens comprising a circular slab of dielectric material of approximately the same radius as that of the unflared portions of said plates, said dielectric lens being placed between and separating said plates so that the flared ends form a waveguide horn, said lens being concentric with said plates;
- and
- a plurality of loosely coupled feed elements disposed symmetrically around the periphery of said lens,
- said dielectric lens being coupled directly to any impinging electromagnetic wave energy without the intervening action of any said feed element and focusing the energy of any electromagnetic plane wave at a focal point near its periphery opposite the point at which the plane wave energy first strikes the lens,
- said loose coupling of said feed elements preventing high absorption of incoming energy by any feed element except that one at the point at which the energy is focused or the two flanking the focal point.
Electromagnetic energy antenna apparatus comprising in combination:
- a lens antenna having a circular lens of dielectric material of constant K, lying between a pair of substantially identically shaped, electrically conductive plates, said dielectric lens being coupled directly to any impinging electromagnetic wave energy and focusing the energy of any impinging electromagnetic plane wave at a focal point near its periphery opposite the point at which the plane wave first strikes the lens, said lens also being capable of acting in the reverse direction;
- and
- a plurality of loosely coupled feed elements disposed symmetrically around the periphery of said lens, the loose coupling of the feed elements preventing high absorption of incoming energy by any feed element except the one or two nearest the point at which the energy is focused by the dielectric lens.
Dependencies are inferred from the claim text.