Determining the Quality factor of resonator

In summary, the speaker is seeking help in determining the quality factor of a piezoelectric rectangular plate MEMS resonator in COMSOL multiphysics. They are using a rectangular plate geometry and have found a desired eigenmode at a specific frequency, but are struggling to determine the quality factor for this mode. They have searched for a formula for Q in the help section, but are unsure of how to calculate it for their specific geometry.
  • #1
mohit21
2
0
Respected members,
PLEASE help me in determining quality factor of a piezoelectric rectangular plate MEMS RESONATOR in COMSOL multiphysics.there is a need to define some 'damping'.where should i define that..
PLS HELP ME ITS URGENT
thank you and best
 
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  • #2
mohit21 said:
Respected members,
PLEASE help me in determining quality factor of a piezoelectric rectangular plate MEMS RESONATOR in COMSOL multiphysics.there is a need to define some 'damping'.where should i define that..
PLS HELP ME ITS URGENT
thank you and best

Welcome to the PF.

How is the quality factor "Q" defined? How are you modelling the mechanical oscillations in COMSOL so far? Can you show us what you have done so far?
 
  • #3
thanks for your quick reply

I am working on piezoelectric (aluminium nitride) vibrating contour mode resonators and filters.i am using COMSOL multyphysics 4.0a.
i have a rectangular plate geometry and i want to find contour mode that i got already.i got desired eigenmode(contour) at some eigenfrequency.
this is the thing i want to design (http://www.seas.upenn.edu/~piazza/Papers/Piazza_JMEMS_jan07.pdf
but i want to find Quality factor according to each eigenfrequency of desired mode.
i search in help there was a formula for Q. they r calculating Q by eigenvalue(lemda) as imaginary part divided by twice real part of lemda.thats ok
but i am getting purely imaginary lemda according to desired mode in comsol.means infinite Q
but it should be some definite value...

i am getting some complex lemdas also.which r not according to desired eigenmode.by formula Q will comes order of e-7 or lesser.

MEANS I DONT KNOW HOW TO FIND Q OF A GIVEN GEOMETRY ??
 
Last edited by a moderator:

1. What is the quality factor of a resonator?

The quality factor, also known as Q factor, is a measure of the efficiency of a resonator in storing and releasing energy. It is calculated by dividing the resonant frequency by the bandwidth of the resonator.

2. How is the quality factor of a resonator determined?

The quality factor of a resonator can be determined experimentally by measuring the resonant frequency and bandwidth of the resonator. It can also be calculated using the material properties and dimensions of the resonator.

3. What is the significance of the quality factor in a resonator?

The quality factor is an important parameter in resonators as it affects the selectivity, stability, and linearity of the resonator. Higher quality factors indicate better performance and efficiency of the resonator.

4. How does temperature affect the quality factor of a resonator?

Temperature can have a significant impact on the quality factor of a resonator. In some cases, an increase in temperature can cause a decrease in the quality factor due to the change in material properties. However, in some resonators, such as quartz crystals, the quality factor may increase with temperature due to the decrease in losses.

5. Can the quality factor of a resonator be improved?

Yes, the quality factor of a resonator can be improved by using high-quality materials, optimizing the dimensions, and minimizing losses in the resonator. Additionally, temperature control and shielding from external factors can also improve the quality factor of a resonator.

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