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:
Feb. 10, 1976
Filed:
Dec. 19, 1973
Raytheon Company, Lexington, MA (US);
Abstract
An antenna element for use in a phased array antenna is disclosed. Such antenna element is a reciprocal device adapted selectively to radiate radio frequency energy of either circular or linear polarization. Such antenna element includes waveguide means for passing radio frequency energy and for radiating such energy; and means adapted to transform the polarization of the radio frequency energy as such passes through the waveguide means to radiate such radio frequency energy selectively with either linear or circular polarization. In a preferred embodiment the just-mentioned means includes a first and a second nonreciprocal quarter-wave plate having field orientations effectively 45.degree. with respect to each other. Such nonreciprocal quarter-wave plates flank a third nonreciprocal quarter-wave plate switchable so that its field orientation is either aligned with the field orientation of the first nonreciprocal quarter-wave plate or, while still aligned as before, turned 180.degree.. Further, the third quarter-wave plate may be switched into a nonenergized state. A reciprocal quarter-wave plate is disposed between the radiating end of the waveguide means and the second nonreciprocal quarter-wave plate. A phase shifter section is disposed between the third nonreciprocal quarter-wave plate and the first nonreciprocal quarter-wave plate. When the field orientations of the first and the third quarter-wave plate are aligned, vertically polarized radio frequency energy introduced into the waveguide means is changed to radiate as horizontally polarized radio frequency energy. When the field orientation of the third quarter-wave plate is reversed by 180.degree., vertically polarized radio frequency energy introduced into the waveguide means is radiated as vertically polarized radio frequency energy. When the third quarter-wave plate is unenergized, vertically polarized radio frequency energy introduced into the waveguide means is changed to radiate as circularly polarized radio frequency energy. The phase shifter section, whatever the polarization of the radio frequency energy passing through, is operative to change, in accordance with a beam steering control signal, the phase of such energy.