P5H-3 A COM Analysis of SAW Tags Operating at Harmonic Frequencies

The operation of surface acoustic wave (SAW) tags at harmonic modes can relax lithography restriction from the frequency raise and archive a good power handling. In this paper a simulation tool for analyzing SAW tags operating at harmonic frequencies is developed. We extended a coupling of modes (COM) model to calculate their harmonic responses by integrating the quasi-static approximation. The considered SAW tags were decimal and had reflectors of single-electrode IDT, three-finger IDT and split-electrode IDT. Finally, some related experiments were implemented: the SAW tags were by micro-electro-mechanical system processes and measured via Network analyzer and a probe station. Experimental results, showing a good agreement with simulation results, prove the feasibility of the proposed simulation tool. Based on all results, we found that the 2nd harmonic of three-finger IDT and 3rd harmonic of split-electrode IDT are effective to achieve a higher operating frequency for SAW tags.