| Authors have already realized 3.0x2.5x1.2 or 2.5x2.0x0.48 mm3 size SAW duplexers for personal communication services (PCS) in US with an excellent temperature coefficient of frequency (TCF) by using the Rayleigh wave on the SiO2/Cu-electrode/120-128YX-LiNbO3 and 36-48YX-LiTaO3 structures. This time, authors intentionally attempted to make the convex portions on the SiO2 film over the gap of interdigital transducers(IDTs). As the results, the calculated and measured results showed the increase of the reflection coefficient and the improvement of the TCF. In addition to them, the measured results showed that a power durability have been drastically improved without any deterioration in the frequency characteristics by making the convex portions on the SiO2 film over the gap of the IDTs. |