Study of loss mechanisms in temperature compensated surface acoustic wave devices based on finite element method analysis using hierarchical cascading technique

Abstract

This paper discusses loss mechanisms of temperature compensated surface acoustic wave (TC-SAW) devices using the SiO2 overcoated 128°YX-LiNbO3 (128-LN) substrate. Analysis is based on the finite element method (FEM) combined with the hierarchical cascading technique and the general purpose graphics processing unit. Three kinds of FEM model, i.e. 2.5D, three dimensional (3D) periodic and full 3D are analyzed without taking additional losses, i.e. material viscous loss, dielectric loss and electrode ohmic loss, and influence of scattering at structural discontinuities is evaluated solely. It is shown that although Q reduction is significant with an increase of the simulation dimension, in other words, that of the number of acoustic scattering mechanisms, estimated Q value is still considerably higher than reported values even for full 3D simulation. This result indicates that acoustic scattering at structural discontinuities is not a dominant loss mechanism in current TC-SAW devices employing the SiO2 overcoated 128-LN substrate.

Enhancement of leaky surface acoustic wave harmonics excitation using bonded dissimilar-material structures

“…8) Furthermore, R-SAWs and LSAWs have been extensively studied. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Our research group reported that a large K 2 and a small TCF can be simultaneously obtained in LT/quartz and LN/quartz structures. 19) Note that some research groups have also investigated a bonded structure comprising an LT thin plate and quartz, and obtained an LSAW resonator with high impedance ratio and large Q factor.…”

From Microwave Acoustic Filters to Millimeter-Wave Operation and New Applications

“…Figure 13 shows calculated admittance of one-port SAW resonator using a SiO 2 /128 • YX-LiNbO 3 structure [49]. Three results are shown.…”

Development and Application of SAW Filter

“…With the increasing communication requirements, the standard surface acoustic wave (SAW) filter has a high temperature drift frequency, which produces nonlinear frequency changes to temperature changes, which seriously affects the filter performance and cannot meet certain strict requirements [ 28 ]. specifications, so BAW filters including thin-film bulk acoustic resonators and solid-mounted resonator filters have been developed to meet this requirement.…”