In this paper, a pattern diversity antenna with switched parasitic elements is presented for wireless LAN application. A wire meander-line antenna on top of a circular metallic ground plane is designed and used as the main radiator. Some conductive rods are installed on the ground plane, around the antenna. Connecting and disconnecting of the rods to the ground plane stirrers the antenna farfield radiation pattern. Two optimized switching categories are used in rods selection. A good impedance matching and low correlated radiation patterns are generated which results to an efficient diversity antenna system. The diversity signals correlation, in a uniform field scattering environment and Rayleigh multipath fading channel, is computed from the complex 3D radiation patterns. It is verified with the measurements accomplished inside a mode stirrer reverberation chamber (MSRC). The received signals correlation coefficient and the diversity gain for selection combining are provided