Mobile two-way connectivity has been receiving much attention recently due to its applications in vehicular satellite communication, telemedicine and next generation of mobile phones (5G). This type of connectivity requires antennas which are not only able to transmit and receive simultaneously, but also capable of independent beam-forming in each band for sensing and tracking purposes. This project investigates the potentials of MEMS-integrated Resonant Cavity Antennas (RCA) and Reflectarrays for these applications. MEMS switches and varactors are monolithic- and hybrid-integrated with these two classes of planar antennas to enable dynamic control of phase over the radiating aperture.