Utilization of RF MEMS tunable capacitors in microwave circuits is rapidly growing up. A low cost and simple production of an RF MEMS tunable capacitor is increasingly demanded. Within this work an RF MEMS tunable capacitor structure with low cost materials and process is successfully developed and characterized. A new process with reduced production time and a less number of fabrication steps by incorporating isolating dielectric materials as part of the top membrane in the RF MEMS capacitor structure is presented. ...