Simulation/Experiment Confrontation, an Efficient Approach for Sensitive SAW Sensors Design

Abstract

Sensitivity is one of the most important parameters to put in the foreground in all sensing applications. Its increase is therefore an ongoing challenge, particularly for surface acoustic wave (SAW) sensors. Herein, finite element method (FEM) simulation using COMSOL Multiphysics software is first used to simulate the physical and electrical properties of SAW delay line. Results indicate that 2D configuration permits to accurately obtain all pertinent parameters, as in 3D simulation, with very substantial time saving. A good agreement between calculation and experiment, in terms of transfer functions (S21 spectra), was also shown to evaluate the dependence of the SAW sensors sensitivity on the operating frequency; 2D simulations have been conducted on 104 MHz and 208 MHz delay lines, coated with a polyisobutylene (PIB) as sensitive layer to dichloromethane (DCM). A fourfold increase in sensitivity was obtained by doubling frequency. Both sensors were then realized and tested as chem-sensors to detect zinc ions in liquid media. 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl} methyl)]methyl] anthracene (TDP-AN) was selected as the sensing layer. Results show a comparable response curves for both designed sensors, in terms of limit of detection and dissociation constants Kd values. On the other hand, experimental sensitivity values were of the order of [7.0 ± 2.8] × 108 [°/M] and [16.0 ± 7.6] × 108 [°/M] for 104 MHz and 208 MHz sensors, respectively, confirming that the sensitivity increases with frequency.

Simulation Study of FEUDT Structure Optimization and Sensitive Film Loading of SAW Devices

“…According to the above parameters, the variation in different sensitive films with thickness is studied, and the influence of the frequency and wave speed of the SAW sensor is simulated and analyzed [ 19 , 20 ].…”

3D Simulation-Based Acoustic Wave Resonator Analysis and Validation Using Novel Finite Element Method Software

“…Nevertheless, there still exist challenges that limit the level of representation accuracy of modern 3D FEM simulation tools available today. This section outlines some of those challenges and presents a review of typical design process based on 3D simulations [27,28].…”

Selectivity in trace gas sensing: recent developments, challenges, and future perspectives

“…Various gas sensing devices can be made of 2D materials, 6,102,255,271 e.g. , chemiresistors, 272,273 field-effect transistors (FETs), 274–278 layered semiconductor heterojunction, 279–281 surface acoustic wave (SAW) sensors, 282,283 conductometric semiconducting gas sensors, 284 impedance sensors. 285 Several theoretical studies show that 2D material-based gas sensors can achieve a detection limit of ppb levels and inclusion of cleansing system by using UV light, the detection limit can reach up to ppt level.…”