Electronic article surveillance system having low profile antennas
CA 1233540 A · Owner: Ici Americas Inc. · Inventors: Williams, Harold B.; Sensiper, Samuel; Fancher, Philip D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An electronic article surveillance system for microwave frequencies (500 MHz and higher) has low profile (i.e. shallow) transmitter antenna arrays and a low profile receiver antenna array, each array comprising a pair of thin metal patches, spaced apart in the normal direction of travel through a surveillance zone, and a thin metal ground plane behind the patches. The patches and ground plane are in spaced parallel relationship. Each metal patch and the adjacent portion of the ground plane together form a cavity resonator which resonates at a desired transmitter or return signal frequency and thereby form a signal radiating or receiving structure. The patch size, patch to ground plane …
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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
- Granted March 1, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 1, 2005.
- 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.