Optimal design on SAW sensor for wireless pressure measurement based on reflective delay line

This paper presents optimal design on wireless pressure micro-sensor based on surface acoustic wave (SAW) reflective delay line. Using the coupling-of-modes (COM) analysis, the device was simulated, and the effect of reflector configuration and interdigital transducer (IDT) structure on the performance of the devices was studied. From the COM simulation results, a 440 MHz SAW-based pressure sensor based on a reflective delay line on 41° YX LiNbO3 with shorted circuit grating reflectors and single-phase unidirectional transducers (SPUDT) structure was developed experimentally. Using the network analyzer, the SAW sensor was wirelessly characterized, and the experiment results were well matched with simulation data. Sharp reflection peaks, low insertion loss and few spurious signals between the peaks were observed. Obtained pressure sensitivity was 2.67°/kPa.