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. 11, 2000
Filed:
Mar. 24, 1997
Warren E Guthrie, Wheaton, IL (US);
Thomas Edmund Szmurlo, Palatine, IL (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A monitor tag having a radio frequency transmitter and a patch antenna. The antenna is in communication with the transmitter and has a first conductive patch and a second conductive patch substantially parallel to each other, and separated from each other by a dielectric material in contact with both patches and having a thickness sufficient to create a gap between the patches wherein the radiation resistance will be controlled during operation of the antenna. The first conductive patch has a dimension of one-quarter or one-half wavelength, depending upon available space and desired pattern. Because the electric field is launched from the gap between the patches and is highly concentrated, bringing the monitor tag close to a metal object or attaching it thereto will have minimal impact on the impedance of the antenna. The monitor tag can be used for a number of purposes including asset protection and identification by affixing respective tags with conventional transmitters to respective metal and nonmetal articles and transmitting chosen respective information about each article. Of particular applicability is a monitor tag device worn by a person such that the wearer can be monitored with respect to chosen parameters as developed for observing or regulating and transmitted or received by the antenna of the present monitor tag invention.