Effect of Guiding Layers and Interdigitated Electrode Structures on the Frequency Behaviour of SAW Sensors

Abstract

The properties of surface acoustic wave (SAW) sensor can be optimized by using a rational structural design. In this work, simulation and experimental studies of ZnO/quartz structure are presented. The effect of the guiding layer on the propagation characteristic and surface displacement of the designed SAW sensor is mainly discussed. SAW sensors with different structures (different input-output interdigital transducer (IDT) ratio, different aperture and different guiding layer) are fabricated via conventional photolithography techniques and measured by network analyzer. The ZnO-based SAW sensor with symmetrical structure (50:50) and larger aperture (1800 μm) shows good frequency behaviour and obtains lower insertion loss. The experimental results are in agreement with the simulation results.