Bidirectional Monopole Antenna Array with Minimized Ground Plane for WLAN Applications

This paper proposes a new design of printed monopole antenna array for WLAN applications. In order to get rid of the parasitic effects of a uniform ground plane on the array feeding network, the metal shape is specifically cut out to minimize its interaction with the monopole while ensuring the proper operation of the array feeding network. Simulations of a 2-by-2, monopole antenna array with the optimized ground plane shape shows that the array performance is significantly improved with miniaturization of ground structure. These results are validated by the measurements showing that the unique shape of the ground structure increases the antenna gain by 1.75 dB and decreases the side lobe level by 5.30 dB with respect to a standard uniform ground.