This paper describes the design and simulation by HFSS simulator of a probe-fed and multi-band Planar Inverted-F Antenna (PIFA) for the 4G mobile networks. The antenna works in 8 bands. Five bands are auctioned by FCC for 4G (LTE and WiMax) such 710 MHz, 1900 MHz (PCS), 2.3 GHz (WCS band), 3.65 GHz (rural 4G) and 5.8 GHz (FCC unlicensed band). The antenna allows working around 910 MHz ISM band. The GPS signal can be received in GPS L₂ band around the frequency 1575 MHz. The antenna offers also a wideband around 8.62 GHz. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S₁₁ parameters, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect mostly the requirements.