Determining the Quality factor of resonator

  • Thread starter Thread starter mohit21
  • Start date Start date
  • Tags Tags
    Quality Resonator
AI Thread Summary
The discussion focuses on determining the quality factor (Q) of a piezoelectric rectangular plate MEMS resonator using COMSOL Multiphysics. The user is struggling with defining damping in their model and is seeking guidance on how to calculate Q based on eigenfrequencies. They mention obtaining purely imaginary eigenvalues, which suggest an infinite Q, while they expect a finite value. The user has already identified the desired contour mode but is confused by the complex eigenvalues that do not align with their expected results. Assistance is requested urgently to clarify how to accurately find the quality factor for their specific geometry.
mohit21
Messages
2
Reaction score
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
 
Engineering news on Phys.org
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?
 
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:

Thread 'Bubble formation in 4 mm gap vessel'

How did you find PF?: Via Google search Hi, I have a vessel I 3D printed to investigate single bubble rise. The vessel has a 4 mm gap separated by acrylic panels. This is essentially my viewing chamber where I can record the bubble motion. The vessel is open to atmosphere. The bubble generation mechanism is composed of a syringe pump and glass capillary tube (Internal Diameter of 0.45 mm). I connect a 1/4” air line hose from the syringe to the capillary The bubble is formed at the tip...
View full post »
Thread 'Physics of Stretch: What pressure does a band apply on a cylinder?'

Thread 'Physics of Stretch: What pressure does a band apply on a cylinder?'

Scenario 1 (figure 1) A continuous loop of elastic material is stretched around two metal bars. The top bar is attached to a load cell that reads force. The lower bar can be moved downwards to stretch the elastic material. The lower bar is moved downwards until the two bars are 1190mm apart, stretching the elastic material. The bars are 5mm thick, so the total internal loop length is 1200mm (1190mm + 5mm + 5mm). At this level of stretch, the load cell reads 45N tensile force. Key numbers...
View full post »

Thread 'Find 3D Printer & Software Resources for Prototype Creation'

I'd like to create a thread with links to 3-D Printer resources, including printers and software package suggestions. My motivations are selfish, as I have a 3-D printed project that I'm working on, and I'd like to buy a simple printer and use low cost software to make the first prototype. There are some previous threads about 3-D printing like this: https://www.physicsforums.com/threads/are-3d-printers-easy-to-use-yet.917489/ but none that address the overall topic (unless I've missed...
View full post »

Similar threads

Need Help Finding Cheap Vibration Testing Equipment
Replies
6
Views
2K
Help with understanding of RF theory-Kinetic inductance parametric amp
Replies
1
Views
2K
Stress Analysis of Lifting Plate With Bail
Replies
1
Views
2K
Help Me Design a Motorcycle Airbox for Charity Racing Series
Replies
3
Views
2K
Oscillator/spring quality vs frequency....
Replies
8
Views
2K
A Advice for 100 MHz resonator
Replies
11
Views
268
Soft/Stable Movement for Parallelogram Mount with Wheel + Printhead
Replies
1
Views
122
Other Questions on quality of research
Replies
1
Views
1K
Calculate quality factor of a damped oscillation from a graph
Replies
7
Views
4K
Finding the resonant frequency of this "discriminator" demod circuit.
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top