Abstract-In wireless communication systems, interference becomes a major problem in limiting the quality of the transmitted and received signals. A common problem in wireless communications is to eliminate the interference signal that is mixed with the original signal. Thus, adaptive beamforming is proposed to eliminate the interference signal. This paper presents an adaptive antenna using a slotted patch antenna for WLANs operated at 2.4 GHz. A reactively steerable antenna concept has been applied. A downhill simplex algorithm is used to maximize the cost function. The radiation pattern of the antenna is controlled by the reactance value connected to each port. From numerical simulation, null is performed for the incoming interference.