SAW Device with IDTs

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I'm trying to create a finite-sized surface acoustic wave device (file attached) with gold electrodes for the IDTs.

Essentially, I'm creating an IDT similar to https://www.comsol.com/paper/download/213121/dixit_paper.pdf but looking at what happens to the wave as it penetrates the piezoelectric substrate without the periodic boundary conditions (since the IDT I fabricate will be finite sized). There are a few simulations I wish to run:

(1) Finite-sized (i.e. no periodic boundary conditions) surface acoustic wave device (2) 3D version of IDT -- i.e. extrude the entire setup along an axis (3) IDT with input and output ports, as in the paper linked.

I cannot seem to get any of these three to work; I've attached files from (1), could someone take a look and see if I'm doing anything in my setup wrong? How would I set up an output port and get the resonance plot?



1 Reply Last Post Jun 24, 2019, 1:06 PM EDT
Dave Greve Certified Consultant

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Posted: 3 months ago Jun 24, 2019, 1:06 PM EDT
Updated: 3 months ago Jun 24, 2019, 1:01 PM EDT

Well for a start: an eigenfrequency analysis on such a large structure is unlikely to be helpful. Use the eigenfrequency analysis on one period to estimate the center frequency and then do frequency domain analysis around that frequency on the entire resonator.

Use the Terminal for input and output IDTs so you can drive one and connect a load to the other. This also makes it easy to calculate the input impedance.

Think about what happens at the boundaries: do you want a PML somewhere?

Use a more carefully thought out mesh. Right now the mesh becomes very large away from the IDT so waves cannot propagate there. And probably finer than needed near the IDT.

3D simulations of a full resonator will be very very demanding computationally.

D.W. Greve

Well for a start: an eigenfrequency analysis on such a large structure is unlikely to be helpful. Use the eigenfrequency analysis on one period to estimate the center frequency and then do frequency domain analysis around that frequency on the entire resonator. Use the Terminal for input and output IDTs so you can drive one and connect a load to the other. This also makes it easy to calculate the input impedance. Think about what happens at the boundaries: do you want a PML somewhere? Use a more carefully thought out mesh. Right now the mesh becomes very large away from the IDT so waves cannot propagate there. And probably finer than needed near the IDT. 3D simulations of a full resonator will be very very demanding computationally. D.W. Greve

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