calculate dielectric constant

Hi..

I′ve a presentation of a patch antenna in September in my university and i was thinking to protect the antenna with Acrylic sheet′s, but i cant find any information about the Dielectric constant of Acrylic..

-Anyone knows the Dielectric constant of Acrylic?

-how can i measure/calculate the Dielectric constant of Acrylic?

Big thanks.

dielectric constant is 3.3
Here is some information on measurement
http://rimstar.org/materials/dielect.../lucitedc1.htm

Enjoy,
Abhishekabs

thanks!

For the next weeks my university will be closed to test the simulations, do you think that 2mm of Acrylic will have a big impact on the performance of the patch antenna (5Ghz)?

The Acrylic will be only for protection ( weather/people thouching it/etc), maybe the acrylic sheet will be 2cms away from the PCB.

I was reading 1 paper & i found that there may be some effect on efficiency.
I have found 1 IEEE paper & I am attaching it here for you.
That may be help.
In that paper coupling effects of closely packed patch antenna are studied.
That is all I know.

Abhishekabs