Study on Loss Mechanisms in I.H.P. SAW Assisted by Full-3D Hierarchical Cascading Technique

This work describes study of loss mechanisms in incredible high performance surface acoustic wave resonator (I.H.P. SAW) on the LiTaO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /Si structure. The full three-dimensional (3D) finite element method (FEM) is carried out with the assistance of the hierarchical cascading technique. Excellent agreement between calculation and measurement can be seen not only for k <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</inf> 2 but also the Bode <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</tex> behavior. The calculated Bode <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</tex> behavior is mainly determined by the number of IDT finger pairs and scarcely influenced by that of reflector fingers. This indicates that SAW diffraction due to finite IDT length is mainly responsible to discrepancy between the periodic and full 3D FEM simulations.