Parametric study of resonant TC-SAW piston-mode configurations

Recent trends in cellular handsets demand SAW resonators with increased performance. Most importantly, improvements in both the resonators' quality factor (Q) and temperature coefficient of frequency (TCF) are needed. The TC-SAW concept employing buried Cu electrodes in SiO
₂
/128°Y-LiNbO
₃
has attracted considerable practical interest in this view, with the requirement that the spurious transverse modes in the structure are suppressed. Thus, practical TC-SAW resonators employ a specific geometry ensuring a piston mode of operation. Here we present a theoretical and experimental parametric study of the piston geometry as function of the resonance frequency and aperture. The extracted scaling rules are subsequently used in the design of RF filters.