Miniaturized magnetoelastic tags using frame-suspended hexagonal resonators

Magnetoelastic tags - also referred to as acousto-magnetic or magnetomechanical tags - are used in wireless detection systems that electromagnetically query the resonant response of the tags. This paper presents miniaturized magnetoelastic tags using hexagonal resonators with an overall size of about ø1.3 mm × 27 μm and a resonant frequency as high as 2.13 MHz. The tags are 100X smaller than typical commercial tags. A unique feature is the frame-suspension, which results in ≈75X improvement in signal amplitude compared to that of non-suspended disc tags with similar size and frequency. This paper also demonstrates that the signal amplitude can be boosted by utilizing signal superposition of an ensemble of tags.