pifa printed in FR4 at 900MHz design?

The resonant frequency of PIFA can be approximate with:

L1 + L2 = λ/4
when W/L1=1 then L1 + H = λ/4
when W=0 then L1 + L2 + H = λ/4

thanks so much for that wonderful layout!

well, i would greatly appreciate if you also present me a printed-layout in FR4 in contrast to a planar-PIFA...
i'd been doing a lot of layouts but still very unmatched about -4dB S11 and off-centered...

thanks again and hoping to hear from you soon!

Hay vfone,

what about the feeding point?

The position of the feeding point for PIFA should be optimized during simulation and during the final tuning, to get the required antenna impedance without using any extra lumped components for matching network.