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:
Apr. 04, 2006
Filed:
Dec. 05, 2001
Ulrich E Mahr, Backnang, DE;
Ulrich E Mahr, Backnang, DE;
Marconi Communications GmbH, Backnang, DE;
Abstract
A cassegrain-type feed for a parabolic antenna is a dual-band feed and employs a waveguide feeding a dielectric cone feeding a subreflector. The waveguide has an end-portion adjacent a narrow end of the cone. The impedance of an inner wall of the cone is modified by the inclusion of a dielectric sleeve of thickness between ⅙ and ¼ of a wavelength relative to propagation in the sleeve at a mean value of the upper of the two frequency bands concerned. The sleeve helps to provide a rotationally substantially symmetric illumination of the subreflector in the upper frequency band and, when used with a parabolic main reflector, a similarly symmetric illumination of the main reflector also. The sleeve may be replaced by a series of grooves formed in the inner wall of the waveguide end-portion, these grooves being nominally ¼ of a mean wavelength deep.