RESONANT TAG CIRCUITS USEFUL IN ELECTRONIC SECURITY SYSTEMS

摘要

A resonant tag circuit is provided which is useful in conjunction with an electronic security system for preventing theft of articles from a protected area. The tag circuit comprises an electrically insulating substrate having a spiral conductive path on each surface of the substrate. The spiral conductive paths are positioned to overlap each other to effect distributed capacitance. The degree of overlap of the distributed capacitance portion of the conductive paths is such that it provides at least 70%, preferably 90% and most preferably 100% of the total overlapping portions of the circuit.