P1L-3 Characteristics of LLSAW in Periodical Systems of Layered Electrodes

Resonant characteristics of longitudinal leaky surface acoustic waves (LLSAW) in infinite periodic interdigital transducers (IDT) with layered electrodes are calculated. An electrode is assumed to be consisted of two parts - under-layer of crystal material and top layer of aluminum. The simplest structure is a periodic array of grooves of rectangular shape etched in the substrate with aluminum (AL) electrodes positioned on tops between adjacent grooves. Such a structure on YZ-cut of-lithium niobate (YZ-LN) shows calculated quality factors of two times larger as compared to AL electrodes on smooth surface with dissipation in electrodes taken into account. As an additional combination the under-layer of titanium-dioxide (TiO₂)-AL is considered. This combination shows quality factors approximately three times larger than the structure with AL electrodes on smooth surface