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Calculating the conductance of the IDT structure

Posted 27 avr. 2021, 04:22 UTC−4 Piezoelectric Devices, Structural & Acoustics, Acoustics & Vibrations Version 5.5 2 Replies

Cai Sylvia
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I have been simulating the IDT structure using the solid mechanics+electrostatics+multiphysics modules recently. Starting by simulating the eigenfrequency of a unit cell to find the wanted mechanical modes with frequency of f, and followed by a step of the frequency domain near f. I want to calculate the conductance (real part of Y11) and the susceptance (imaginary part of Y11) for this IDT structure for further analysis of the IDT efficiency. I come up with two problem: (1) the simulation result always shows that teh conductance is 0 while the susceptance seems reasonable. (2) I have read some papers, in such system, there are two frequencies need for calculating efficiency, fs(with setting the voltage across the IDT to 1V) and fp( with open terminal floating boundary condition for the electrodes). However, when i set the floating boundary in step 2, I coudn't calculate the Y11 in the global calculation. Did i set the condition right?

2 Replies Last Post 29 avr. 2021, 10:26 UTC−4
Dave Greve
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Posted: 4 years ago 27 avr. 2021, 12:04 UTC−4

  1. The conductance will be zero unless there is some sort of loss in the system. A perfectly matched layer or low-reflecting boundary on the bottom surface will do the trick.

  2. You can't calculate Y11 if there is no electrical terminal connected to a source. If you sweep frequency with one terminal driven you should be able to see both series and parallel resonances. This assumes you are using periodic boundary conditions, you would essentially be calculating the admittance of one section of an infinite resonator.

1. The conductance will be zero unless there is some sort of loss in the system. A perfectly matched layer or low-reflecting boundary on the bottom surface will do the trick. 2. You can't calculate Y11 if there is no electrical terminal connected to a source. If you sweep frequency with one terminal driven you should be able to see both series and parallel resonances. This assumes you are using periodic boundary conditions, you would essentially be calculating the admittance of one section of an infinite resonator.
Walter Frei COMSOL Employee

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Posted: 4 years ago 29 avr. 2021, 10:26 UTC−4

Within the Electrostatics interface, you can also include loss via the "Conduction Loss (Time-Harmonic)" sub-feature that can be added to any "Charge Conservation" or the "Piezoelectric Material " solid mechanics feature.

Best Regards,

Within the Electrostatics interface, you can also include loss via the "Conduction Loss (Time-Harmonic)" sub-feature that can be added to any "Charge Conservation" or the "Piezoelectric Material " solid mechanics feature. Best Regards,

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