A Comparison of Surface Acoustic Wave (SAW) Delay Line Modelling Techniques for Sensor Applications

This paper describes a comparative modelling study of Surface Acoustic Wave (SAW) devices. The Surface Acoustic Waves (SAWs) are generated and received by the interdigital transducer (IDT) on a piezoelectric substrate. SAW device design parameters like piezoelectric substrate, structure of IDT, number of finger pairs, device frequency and etc., are optimized and its frequency responses achieved by using three models, namely, Impulse response Model, Crossed-field Equivalent Circuit Model and Coupling-of-Modes Model. The modelling of ST-X Quartz based SAW Delay line with 40 finger pairs operating at a centre frequency of 300 MHz has been undertaken and its modelled frequency response studied via three models. Employing a custom made MATLAB® algorithm, the device is modelled by varying its design parameters. The modelled results are analyzed and compared for attaining better performances for potential applications in a SAW sensor.