[SOLVED] SAW resonator: Series and parallel resonant frequency shift with external impedance

[teleko7]

Hi

My question is simple: I've read in several articles and AN-s that the resonant frequencies of a SAW resonato (whose equivalent circuit can be aproximated by an RCL with a C in parallel) can be shifted by adding a parallel C or a series C.

Being resonant frequencies given by the properties of the SAW material and being the electric model just that, a MODEL, is it possible to alter mechanical properties using external electric impedances?

Thanks in advance, regards.

Iban

 

[FvM]

Consider that mechanical and electrical quantities are coupled by the piezo transducers. In so far the general answer is yes, the resonance frequency is affected by the connected electrical circuit. Similar a crystal's resonance frequency can be pulled by an external capacitor.

How much depends on the parameters of the mechanical resonator, particularly the coupling to the electrical circuit. In case of a crystal, the adjustment range is a few 100 ppm.

 

[teleko7]

Hi FvM

Thanx!!