Design of a Phase Readout Circuit For SAW Sensors With an Equivalent Circuit Model

Surface acoustic wave (SAW) sensors have been extensively investigated in recent years due to their wide applications, detecting SAW in diverse contexts. To embed these sensors in real-life applications, it is necessary to design application-specific circuits to optimize cost, power consumption, and space. During the design of such circuits, an engineer must consider specific SAW device characteristics, which is facilitated by equivalent models that can be simulated along with the surrounding electronics in the time-domain. These models are rare in SAW literature, and their usability for circuit co-simulation is not discussed. In this work, we explore a recently published model and how it behaves in a bigger-scale system. To do so, we demonstrate the design of a phase-shift circuit, which allows to read out perturbations on a SAW sensor based on the phase delay caused by a perturbation. All our simulations were performed in LTSpice, based on a Love wave sensor resonant at 116 MHz.