Computational Analysis of Mass Loading Effects in Multilayer SAW Resonators With Variable IDT Thickness

ABSTRACT This study reports a computational modeling and analysis of one‐port multilayer surface acoustic wave (SAW) resonators, with the investigation of the mass loading effect due to variation of Interdigital Transducer (IDT) thickness. In this paper, a sensing mechanism has been proposed that utilizes an improved mass‐loading effect on two different IDT materials, i.e., aluminum (Al) and gold (Au), resulting in much higher sensitivity as compared to other IDT materials used earlier. This mechanism relies on a greatly improved mass‐loading effect of both electrodes formed directly on the piezoelectric substrate. The thickness variation for both the IDT electrodes ranges from 0.1 μm < h IDT < 0.5 μm. Due to the Al IDT thickness variation, the resonant frequency ( f r ) reduces from 900.71 MHz to 889.19 MHz, whereas the thickness of the other Au IDT results in a decrease of fr from 834.64 MHz to 627.21 MHz. The corresponding mass sensitivity for both the devices with different IDT materials was compared, and finite element analysis (FEA) of device parameters, phase velocity ( v p ), admittance (Y11), electromechanical coupling coefficient (K 2 ), Q factor, and S‐parameters (S11) were computed. The findings presented in this proposed work serve as a valuable resource to optimize SAW resonator designs for a wide array of sensing and communication systems, advancing the state‐of‐the‐art in these fields.