Parallel Plate Capacitor Fringing

[tommyers]

Hi,

I am experimenting with a simple Parallel Plate Capacitor arrangement in order to measure the dielectric of the material between the plates - air, 1 and polycarbonate, 2.9 at this stage. I would eventually like to further this technique to a fringing sensor arrangment, but first I need the following issues resolving.

The plate separation is significant compared with the plate area i.e plate area, A = 1586mm^2 and the plate separation, d = 9.8mm. Using the elementary capacitor equation, C = (Eo x Er x A)/d does not include the fringing effect caused by such A/d ratio. Therefore my measurements are out with my calculations, in some cases by 40%.

I would like a method of modelling the fringing effect so I may gauge the total capacitance in theory, and therefore the resulting dielectric, before carrying out the experiment.

I have looked at many methods including the Boundary element method and such like. I would appretiate if someone could guide me through the modeling process either by example or recommendation of websites / texts / tutorials or books.

Ultimately it would be nice to carry out such calculations and simulations using software so any recommendations using this would also be useful.

I look forward to hearing your thoughts and comments.

Regards

Tom Myers

[Fu-Kwun Hwang]

It can be simulated with numerical method: put laplace/posisson equstion into numerical form.
You can check out standard textbook about numerical method.

[tommyers]

Hi,

Could you please be more specific and maybe provide examples or references to textbooks.

Regards

Tom

[EduZer]

   Yeah can you give some examples or any reference textbook.,I really want to know it..,




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[Fu-Kwun Hwang]

For example:  Numerical recipes Home page at http://www.nr.com/