Magnetic antenna system having independently controllable electrical field shielding and magnetic field balance
CA 2023253 C · Owner: Monarch Marking Systems, Inc. · Inventors: Cordery, Robert A.; Hartings, Michael F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magnetic antenna system particularly useable in electronic article surveillance systems for detecting the presence of a resonant tag utilizes multiple loop shielded transmitting and receiving antennas. The antennas employ shield structures that are designed to minimize the electric field response and to provide a balanced magnetic field response. The magnetic field responses of different ones of the loops in each of the antennas are different and the loops are oriented so that more responsive loops of the transmitting antenna are positioned opposite less responsive loops of the receiving antenna and vice versa in order to reduce the coupling between antennas without reducing the …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed August 14, 1990 and granted April 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 14, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 14, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.