868mhz inverted f antenna

Well an 868MHz antenna is going to be pretty large.
Make sure you use a substrate with a high/lager Dielectric constant.
The "Inverted F" is a little more compact, but I don't know who good it's
performance is compared to a typical Dipole.

Good luck

this might help

http://www.rfm.com/corp/appdata/antenna.pdf

Thanks
I downlode