your question is slight not clear, and needs to be elaborated a little more.

A SAW transducer becomes sensitive to an external stimuli (in the propagation path) when the acoustic velocity get changed, and this will cause a change in its designed center frequency.

1) Do You want to study the pressure sensitivity of a SAW transducer, and want

     to know how to apply the pressure on the SAW device.

2) Similarly you want apply voltage (DC or AC, what frequency) to the SAW device, and then observe how sensitive is the SAW device ( change in its center frequency), and wish to know how to apply this dc/ac voltage to be detected.

If you can clarify a little bit more, it will be convenient to understand the question.

I am enclosing one paper, see if it is of interest to you.

K. Sreenivas

Sensitivity of a surface acoustic wave transducer?

Dear Prof. Sreenivas,

Thank you for your response.

Sorry for the ambiguity.

In a conventional ultrasound transducer we have a sensitivity mentioned in certain Volts/Pa. Similarly for an input IDT which converts voltage to acoustic wave (which I feel can be correlated to pressure), can we form a similar value? Please let me know If I still haven't made it clear.

Thanks,

Rahul Kishor

Dear Prof Reddy,

Yes, I have seen electromechanical coupling coefficient. What I am interested is to know if we can find out the SAW displacement (or pressure) for a given voltage input to an IDT and vice versa. Can we get this information from the coupling coefficient?

Thanks,

Rahul Kishor

Dear Rahul,

first of all, you should make sure that your IDT has an impedance of 50Ohm at the working frequency if you talk about voltage. Otherwise, you should refer to the load power (forward - reflected power), instead of voltage, giving you a correct indication of how much power is fed to the IDT.

Regarding the amplitude: There are papers dealing theoretically with the amplitude achievable for a given IDT (e.g. 10.1109/TUFFC.2003.1176527). 3D FEM simulations of SAWs are still not feasible at this point of time.

For practical measurements - which I would always recommend if you need exact values - you would need to have access to a laser vibrometer (e.g. the UHF120). Please keep in mind, that SAWs are subject to diffraction! Therefore, the wavefield parameters (amplitude and phase) change with distance from the IDT...

Best regards, Andreas