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:
May. 27, 2004
Brent F. Balch, Fort Lauderdale, FL (US);
John O'connell, Cork, IE;
William H. Hurd, Rochestown, IE;
Tom Spalding, Cork, IE;
Brent F. Balch, Fort Lauderdale, FL (US);
John O'Connell, Cork, IE;
William H. Hurd, Rochestown, IE;
Tom Spalding, Cork, IE;
Sensormatic Electronics Corporation, Boca Raton, FL (US);
Abstract
A system for minimizing the effect of null zones in an interrogation zone of a marker detection system. The system includes a reference antenna system configured to produce a first reference electromagnetic field during a first time period. The antenna system also includes a phase canceling antenna system configured to produce a second electromagnetic field substantially in phase with the reference electromagnetic field during the first time period and a third electromagnetic field substantially out of phase with the reference electromagnetic field during the first time period. The phasing of the first field or the second and third fields may be continuously switched while the phase of the other is held constant. A method of spatially shifting null zones in an interrogation zone of a marker detection system is also provided.