RF Micro-Electro Mechanical Systems (MEMS) have been developed during the last decade with several applications for commercial as well as space and military sub-systems [1-6]. Technological processes encompassing the utilization of typical microelectronic substrates like alumina, GaAs and Silicon have been considered for the realization of micro-switches by surface micromachining. True time delay lines (TTDL), single port multiple throw (SPMT), matrices and phase shifters take benefit from the low insertion loss, all passive and distortion-free environment offered by RF MEMS. Antenna re-configuration through digital phase shifters based on RF MEMS switches are currently studied.Low cost ceramic materials like the Low temperature Co-fired Ceramic (LTCC) have been investigated for both device manufacturing and packaging purposes, with very promising results in terms of the integration solutions of the single components. In particular, LTCC could be used for 2D structures, analogously to conventional substrates, but it is also suitable of 3D manufacturing by combining buried interconnections with surface mounted or micro-machined devices. Polymeric materials like SU-8 are also very appealing for the easy device fabrication by means of simple photolithographic processes and very good out-gassing properties. Bulk micromachining, originally developed on GaAs and Silicon substrates for membrane supported RF antennas and filters, is the natural complement with respect to the surface processes in complicated structures, with the possibility to obtain via holes and cavity resonators. Chemical and physical etching techniques (wet …