MicroElectroMechanical Systems, MEMS, are systems based on a range of techologies whereby tiny mechanical elements, both sensors and actuators, can be implemented.It turns out that these elements have excellent system properties.The elements are often interfaced to microelectronical driving or sensing components (ICs) by appropriate packaging or on the same silicon wafer. The semiconductor silicon is not only good for making electronics but its material properties are extremely good.Thus, Micro electromechanical systems (MEMS) refer to a collection of micro-sensors and actuators, which can react to environmental change under micro- circuit control. The integration of MEMS into traditional Radio Frequency (RF) circuits has resulted in systems with superior performance levels and lower manufacturing costs. The incorporation of MEMS based fabrication technologies into micro and millimeter wave systems offers viable routes to ICs with MEMS actuators, antennas, switches and transmission lines. The resultant systems operate with an increased bandwidth and increased radiation efficiency and have considerable scope for implementation within the expanding area of wireless personal communication devices.