ELEKTRONISCHES SYSTEM ZUR UEBERWACHUNG VON GEGENSTAENDEN UNTER BENUTZUNG EINER MARKE MIT EINEM LC-RESONANZKREIS MIT AUSGETEILTER KAPAZITAET.

摘要

An electronic article surveillance system and a marker for use therein, which marker comprises a tuned resonant circuit including inductive and capacitive components formed of a laminate of a dielectric and conductive-multiturn spirals on opposing surfaces of the dielectric, wherein the capacitive component is formed as a result of distributed capacitance between the opposed spirals, and wherein the circuit thereby resonates at at least two predetermined frequencies which are subsequently received to create an output signal. An electrical connection is desirably provided between predetermined portions of the opposing spirals to lower the resonant frequencies.