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:
Nov. 30, 2004
Filed:
Oct. 27, 2003
Niels Christoffers, Duisburg, DE;
Juergen Niederholz, Kerken, DE;
Dirk Hammerschmidt, Heiligenhaus, DE;
Gerd Vom Boegel, Wuelfrath, DE;
Abstract
The present invention relates to a transponder reading device for reading out a plurality of inductive passive transponders having a resonant circuit. A transmitter is provided to create an alternating magnetic field having an operating frequency f , in which the number of transponders may be placed such that same are magnetically coupled to each other. A retuning means is further provided which is arranged in the alternating magnetic field and has such a frequency-dependent impedance that a voltage induced in the resonant circuits of the transponders by the alternating magnetic field has a maximum in the range of the operating frequency f .