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:
Jun. 21, 2005
Filed:
Mar. 03, 1999
Michael John Camille Marsh, Johannesburg, ZA;
Trevor Meredith Hodson, Randburg, ZA;
Michael John Camille Marsh, Johannesburg, ZA;
Trevor Meredith Hodson, Randburg, ZA;
Trolley Scan (Proprietary) Limited, Johannesburg, ZA;
Abstract
An identification system is provided for identifying a plurality of randomly aligned object-based transponders () passing through a predetermined reading volume. A reader () includes multiple transmitting and receiving antenna arrays () which are arranged sequentially to transmit interrogating and energizing fields () into the reading volume, with each energizing field having a different polarisation. Each transponder () is arranged to be powered by at least one of the interrogating and energizing fields, and includes a short term memory module () which is arranged to record the successful transmission or otherwise of the identification signal of the transponder () and to retain the record in the absence of a power supply to the transponder. The short term memory module has a retention time longer than any predicted interruption of power supply to the transponder via one of the energizing fields within the reading volume. The minimum memory retention time is typically the time period taken for the sequential transmission of all but one of the interrogating and energizing fields () during an interrogation cycle.