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. 23, 2002
Filed:
Apr. 30, 2001
Donny V. Lee, North Port, NY (US);
Applied Wireless Identifications Group, Inc., Monsey, NY (US);
Abstract
The present invention features an improved radio-frequency identification (RFID) reader which operates with a low power consumption and which may tolerate a wide fluctuation in input voltages. The RFID reader is housed so that the influence of its physical surroundings, especially metallic objects, on system performance is minimized. A pre-compensation metal plate is used to stabilize the self-resonant frequency of the reader, even in the presence of large metal masses. The pre-compensation plate may be formed from aluminum or another non-ferrous material or, for long-range RFID readers, from ferrite or another similar, high magnetically permeable material. In addition, the RFID reader features improved sensitivity so that the effective operating distance is maximized. Also, the operating frequency is dynamically controlled in discrete steps of 10 Hz or less so that the effects of component parameter drift, temperature change, or other external factors are minimized. The RFID reader also automatically adapts itself to the requirements of an external access control system to which it is attached.