Study on Suppression of Higher-Order Modes in I.H.P. SAW Devices

In this paper, a suppression technique of higher-order mode spurious responses in I.H.P. SAW devices on a LiTaO3/SiO2/SiN/Si substrate is discussed. Behaviors of the spurious responses with structure parameters are analyzed using two-dimensional FEM and, on the basis of the analysis, the parameters are optimized to suppress the higher-order mode responses. As a result, suppression of the spurious modes with keeping other characteristics such as Bode-Q and fractional band width is successfully confirmed on fabricated resonators. Using this technique, I.H.P. SAW devices can be applied to the multiplexer configuration.