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 wanna design (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 ??
I KNOW BY DEFAULT COMSOL TAKE ZERO DAMPING.
PLS SIR TELL ME WHERE AND HOW SHOULD I PROVIDE DAMPING IN COMSOL????
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 wanna design (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 ??
I KNOW BY DEFAULT COMSOL TAKE ZERO DAMPING.
PLS SIR TELL ME WHERE AND HOW SHOULD I PROVIDE DAMPING IN COMSOL????