(19)
(11) EP 0 133 317 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.03.1985 Bulletin 1985/13

(43) Date of publication A2:
20.02.1985 Bulletin 1985/08

(21) Application number: 84108951

(22) Date of filing: 27.07.1984
(84) Designated Contracting States:
AT BE CH DE FR GB IT LI LU NL SE

(30) Priority: 02.08.1983 US 519566

(71) Applicant: ICI AMERICAS INC.
 ()

(72) Inventors:
  • Sensiper, Samuel
     ()
  • Williams, Harold B.
     ()
  • Fancher, Philip Daniel
     ()

   


(54) Electronic article surveillance system


(57) @ An electronic article surveillance system for microwave frequencies (500 MHz and higher) has microstrip antenna arrays each array comprising a dielectric substrate having a plurality of metal patches, spaced apart in the normal direction of travel through a surveillance zone, on one side and a metal ground plane on the other side. 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 spacing, and spacing between patches are determined by the desired resonant frequency.






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