Distributed capacitance LC resonant circuit

Claim 2

An electronic article surveillance system comprising a transmitter for transmitting radio frequency energy at at least two predetermined frequencies, a marker containing a circuit comprising a dielectric sheet having on each surface thereof a conductive multi-turn spiral each turn of which forms a substantially closed loop and is in substantial registration with an opposing turn of the spiral on the opposite surface, each of the multi-turn spirals being oppositely wound with respect to each other when both are viewed from the same side of the sheet to thereby form a series of closed loops having both inductive and distributed capacitive components which in combination resonate at at least said two predetermined frequencies, and a receiver for receiving signals resulting from the circuit resonating at said two predetermined frequencies and for creating an output signal in response to the receipt of said resultant signals.

Claim 3

A marker for use in an electronic article surveillance system having a transmitter for producing a radio frequency electromagnetic field periodically varying at at least two predetermined frequencies, and a receiver for receiving signals resulting from the interaction of the marker with the field, and for creating an output signal in response to the receipt of said resultant signals, wherein said marker contains a circuit comprising a dielectric sheet having on each surface thereof a conductive multi-turn spiral each turn of which forms a substantially closed loop and is in substantial registration with an opposing turn of the spiral on the opposite surface, each of the multi-turn spirals being oppositely wound with respect to each other when both are viewed from the same side of the sheet to thereby form a series of closed loops having both inductive and distributed capacitive components which in combination resonate at at least said two predetermined frequencies upon absorption of energy from said field at said frequencies.

Claim 4

A marker for use in an electronic article surveillance system having a transmitter for producing a radio frequency electromagnetic field periodically varying at at least two predetermined frequencies, and a receiver for receiving signals resulting from the interaction of the marker with the field, and for creating an output signal in response to the receipt of said resultant signals, wherein said marker contains a circuit comprising a dielectric sheet having on each surface thereof a conductive multi-turn spiral each turn of which forms a substantially closed loop and is in substantial registration with an opposing turn of the spiral on the opposite surface, each of the multi-turn spirals being oppositely wound with respect to each other when both are viewed from the same side of the sheet to thereby form a series of closed loops having both inductive and distributed capacitive components which in combination resonate at at least said two predetermined frequencies upon absorption of energy from said field at said frequencies.