Design and modeling of a passive wireless SAW transponder

In this work, a finite element analysis was employed to analyze the second order effects of a passive surface acoustic wave (SAW) transponder. The second order effects, which occur due to the electrode perturbation and wave reflection, were analyzed using a two-dimensional finite element analysis method. A 31-bit Pseudo Random (PN) code sequence was implemented to demonstrate the second order effects on different configurations of the SAW transponder. Analyses of the response has shown that the second order effects on the impulse response become increasingly significant as the device operated in a high frequency (915 Mz) with high data rate (31bit). These quantitative analyses of the second order effects provide insights for designing high performance SAW transponders for high frequency applications. The result also shows that the output signal can be enhanced by increasing the number of input interdigital transducers (IDT).