The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 15, 1977
Filed:
Oct. 20, 1975
John W Greiser, Marina Del Rey, CA (US);
Itek Corporation, Lexington, MA (US);
Abstract
A circularly polarized, broad-beamed antenna system capable of effectively covering the entire bandwidth of from about 0.5 GHz to about 18 GHz or higher. The system provided comprises a generally conventional planar spiral antenna modified by having the outer ends of its arms terminated by a bifilar helix. The bifilar helix is positioned behind the planar spiral and at 90.degree. to it. By proper coupling of the two antenna portions, it has been found that within the 2 to 18 GHz range, the planar spiral operates as if the helix were not present, while below 2 GHz, the spiral functions as a transmission line feeding the helix and the helix radiates essentially all of the energy from the antenna. The antenna system provided is approximately the same size as conventional 2 to 18 GHz cavity backed spiral antennas and generally satisfies all of the physical constraints and limitations placed upon airborne radar-warning systems.