Frequency Domain Acoustic-Based Subharmonic Tags for Far-Field Identification

Abstract

<p>We report on the design and performance of the first prototypes of a new class of Ultra-High-Frequency (UHF) subharmonic tags (SubHTs) relying on a set of Surface Acoustic Wave (SAW) resonators to address a remote identification functionality directly in the frequency domain, while requiring narrowband interrogation signals to ensure 32-bits or higher encoding data capacities (EDCs). The reported SubHT prototypes leverage the dynamics of high quality factor (Q) SAW resonators, combined with those of time-modulated solid-state components, to enable a far-field passive identification without requiring any batteries, any active components or any ad-hoc memory devices. Through the demonstration of the SubHT prototypes reported here, we have unveiled a new path towards the adoption of SubHTs for logistics and tracking, as well as in future massive deployments of wireless sensor nodes (WSNs). Even more, the SubHTs discussed in this work provide their readers with an unprecedented immunity to electromagnetic clutter, multi-path and self-interference, creating unique means to identify any items from a far-field distance, even in indoor uncontrolled electromagnetic environments.<br> </p>