This work proposes a smart planar microstrip antenna that can be reconfigured and controlled by RF-MEMS, and is based on a reconfigurable parasitic structure. The antenna structure is based on an omnidirectional active element surrounded by a series of reconfigurable parasitic microstrip elements, which are connected to RF-MEMS switches that are used to electronically modify the state of the parasitic elements. The goal of the parasitic microstrip structure is to permit the steering of the main lobe of the antenna, place zeros in the radiation pattern in order to avoid interfering signals and maximize the signal-to-noise ratio. The prototype of the antenna was designed, fabricated and assessed experimentally. To assess the effectiveness and potentialities of the proposed prototype, some representative numerical and experimental results are reported and compared.