Enhancing magneto-impedance modulation using magnetomechanical resonance

A system, comprising:

• a first transmitter to transmit an excitation signal within a surveillance zone;
• a security tag to receive said excitation signal, said security tag comprising a magnetoimpedance marker positioned within said security tag body, said magnetoimpedance marker comprising magnetostrictive material configured to resonate at a resonant frequency, said marker to receive a first excitation signal and modulation signal to generate a modulated reply signal, and a second excitation signal to cause said marker to resonate at said resonant frequency, with said resonance to cause said modulated reply signal to have an increase in gain;
• a receiver to receive said modulated reply signal;
• and
• a controller to detect said security tag within said surveillance zone and output a detect signal.

A method, comprising:

• receiving a first excitation signal at a marker;
• generating a reply signal in response to said first excitation signal;
• receiving a modulation signal at said marker;
• modulating said reply signal in response to said modulation signal to form a modulated reply signal;
• and
• receiving a second excitation signal at said marker, said second excitation signal to cause said marker to resonate at a resonant frequency, with said resonance causing an increase in gain of said modulated reply signal.