Use of Dielectric Stripes for Transverse Mode Suppression for Surface Acoustic Wave Resonators

This paper proposes use of dielectric stripes for the piston mode operation of surface acoustic wave (SAW) resonators. Lack of conductivity allows us to place the stripes directly on IDT electrodes. This technique is applied to incredible high-performance (I.H.P.) SAW devices using 42°YX-LiTaO3 with large metallization ratio and it is shown that use of SiO2 stripes is effective for transverse mode suppression. Note that the conventional “hammer-head” design is not effective in this case. Another interesting feature is the fact that the stripes can be displaced from the IDT aperture edges. Then impact of SiO2 position is examined for SiO2 stripes on transverse mode suppression.