ELECTRONIC ARTICLE SURVEILLANCE SYSTEM

摘要

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.