Radio frequency microelectromechanical system (RF-MEMS) switches have demonstrated superior electrical performance (lower loss and higher isolation) compared to semiconductor-based devices to implement reconigurable microwave and millimeter(mm)-wave circuits. In this chapter, electrostatically actuated RF-MEMS switch conigurations that can be easily integrated in uniplanar circuits are presented. The design procedure and fabrication process of RF-MEMS switch topologies able to control the propagating modes of multimodal uniplanar structures (those based on a combination of coplanar waveguide (CPW), coplanar stripline (CPS), and slotline) will be described in detail. Generalized electrical (multimodal) and mechanical models will be presented and applied to the switch design and simulation. The switch-simulated results are compared to measurements, conirming the expected performances. Using an integrated RF-MEMS surface micromachining process, high-performance multimodal reconigurable circuits, such as phase switches and ilters, are developed with the proposed switch conigurations. The design and optimization of these circuits are discussed and the simulated results compared to measurements.