Investigation of the Temperature Properties of the I.H.P. Structure and Its Application for Filters on Surface Acoustic Waves

The temperature properties of the incredible high performance (I.H.P.) structures on a multilayer lithium tantalate/silicon dioxide film/silicon substrate have been studied; these structures are used to improve the characteristics of devices on surface acoustic waves. Test structures have been simulated by the finite-element method in the COMSOL software and the temperature coefficient of frequency has been calculated. The calculated transfer coefficients of a resonator filter on a conventional single-crystal 36°YX-cut lithium tantalate substrate and an I.H.P. filter are compared at different temperatures. It is shown that the temperature coefficient of frequency can be minimized by fitting the thicknesses of the substrate layers. A comparison shows that the results obtained are in good agreement with the known data. The practical importance is that the simulation results and calculated parameters can be used for designing devices of different classes based on multilayer substrates (including those with I.H.P. structures).