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:
Dec. 26, 1995
Filed:
Oct. 21, 1994
Robert J Zavrel, Jr, Scotts Valley, CA (US);
Metricom, Inc., Los Gatos, CA (US);
Abstract
An antenna array for direction-agile applications, such as r.f. packet mesh networks, employs a plurality of quarter-wave radiators disposed normally to a ground plane on a dielectric backing and switching elements for selecting a desired receiving direction and transmission direction and minimizing interference from signals in opposing directions. A control system selects and switches direction rapidly enough to receive and transmit digipeating signals in selected different directions using the phasing and switching elements. A specific embodiment employs eight radiators of 0.2625 electrical wavelengths (quarter wave plus 5%) disposed equidistant along a circle within a circular ground plane in a pattern which is 1/4 wavelength from the outer boundary of the ground plane, each radiator being disposed at least 0.15 wavelengths to about 0.25 wavelengths from adjacent radiators in a circular pattern. The antenna is characterized by eight electronically switchable radiating directions (at 45.degree. intervals) with at least 20 dB front to back ratio and a 3 dB beamwidth of 64.degree.. Pairs of radiators form parasitic elements, driven elements and reflectors with spacing selected as a modest compromise from the ideal spacing to allow electronically selectable directionality using identically-spaced elements acting as driven elements, parasitic elements and reflector elements. The driven elements are slightly reactively fed.