Periodic Analysis of Surface Acoustic Wave Resonator with Dimensionally Reduced PDE Model Using COMSOL Code

Abstract

Radio-frequency (RF) surface acoustic wave (SAW) resonators used as filters and duplexers are mass-produced and widely used in current mobile phones. With the numerous emergences of the diverse device structure, a universal method used for the accurate and fast simulation of the SAW resonator calls for urgent demand. However, there are too many instances where the behavior of the entire acoustic resonator cannot be characterized rapidly and efficiently due to limitations in the current computer memory and speed. This is especially true for SAW resonators configured with long arrays of inter-digital transducers (IDTs), and we have to resort to a periodic analysis. In this paper, the previously reported generalized partial differential equations (PDE) based on the two-dimensional finite element method (2D-FEM) model is extended to analysis for the periodic structure of the SAW resonator. We present model order reduction (MOR) techniques based on FEM and periodic boundary conditions to achieve a dimensionally reduced PDE model without decreasing the accuracy of computations. Examples of different SAW devices, including the regular SAW, IHP-SAW and TC-SAW resonators, are provided which shows the results of the periodic analysis compared with the experimental results of the actual resonators. The investigation results demonstrate the properties of the proposed methodology and prove its effectiveness and accuracy.

Optimization of Surface Acoustic Wave Resonators on 42°Y-X LiTaO3/SiO2/Poly-Si/Si Substrate for Improved Performance and Transverse Mode Suppression

“…Without a loss of generality, the surface acoustic wave is assumed to propagate in the direction on a multi-layered structure. In order to simplify the solution while maintaining a good enough accuracy, the full-scaled 3D finite element model (FEM) was decomposed into a double-finger structure with one period interdigital transducer (IDT) [ 21 , 22 , 23 , 24 , 25 ]. In addition, a substrate with a perfect matching layer set to the bottom for absorbing the wave propagated into the substrate was constructed.…”

Fractional Bandwidth up to 24% and Spurious Free SAW Filters on Bulk 15°YX-LiNbO3 Substrates Using Thickness-Modulated IDT Structures

“…Quasi-3D FEM simulations of the acoustic propagation characteristics of the Rayleigh and SH modes on the 15°YX-LiNbO 3 at different normalized electrode thicknesses h Cu /λ were carried using the structural mechanics module in COMSOL software [ 26 ]. In the FEM model, Cu is defined as the IDT electrode material, and the wavelength λ and metallization ratio of the SAW resonators are 2 μm and 0.5, respectively.…”

Design and Analysis of Interdigital Electrode Parallel Layout of Multilayer SAW Devices

“…Reference [10] proposed a sensing method for extremely high temperatures using an Al2O3/IDT/AlN/Metal/Si composite surface acoustic wave device structure. Reference [11] proposed a model reduction (MOR) technique based on finite element and periodic boundary conditions, which can be used without reducing computational accuracy. Reference [12] proposed a highfrequency surface acoustic wave resonator based on a sandwich interdigital transducer, which adopted a multi-layer structure of diamond/AlN/IDT/AlN/diamond.…”