capacitively-fed stacked patch

I was wondering if someone can tell me which materials i should use for substrate material ( εr=2.32, 1 cm), and where i can buy it.

Does capacitor patch also need to be circle, and could someone give me exact dimension of capacitor patch that i should use, i don't know how calculate it.

Thanks

The value 2.32 for the dieletric constant must correspond to a PTFE-based substrate. (PTFE = poly-tetra-fluoro-ethylene, also known by the commercial name "teflon".)

It seems to me that evidently the drawing is wrong, o at least unclear.
The feeding patch is on a substrate of 0.05 cm width (not 1 cm), 1 cm above the ground plane, and between the ground plane and the feeding patch there is air. The capacitor patch should be in the lower layer of the above mentioned substrate.

Regards

Z

This is the text from article that i used for parameters and dimensions of antenna

It's from this article
http://www.arpnjournals.com/jeas/res...s_0110_283.pdf