RF MEMS and their applications in NASA's space communication systems

Several novel uses of RF MEMS actuators and the fabrication processes used to fabricate them are presented. It is shown that RF MEMS switches may be built using standard electronic fabrication processes with low insertion loss. Furthermore, these actuators may be used to build variable capacitors, or varactors, with low loss. Thus, RF MEMS actuators may replace GaAs MESFET transistor switches and diodes in standard phase shifters with a savings of 3.5 dB in insertion loss. Moreover, the flexibility to alter the size and shape of metal structures leads to such possibilities as reconfigurable antennas, and the precise fabrication of micron sized components enables the fabrication of new components. Fabricating MEMS components relies on the removal of sacrificial layers to free the moving parts, and this step still affects yield in many processes. Also, the reliability and lifetime of mechanical moving parts and the wear of contacts that must be made and broken thousands of times a second are not fully understood. Thus, while the potential is great, R&D must still occur before MEMS components are available in the commercial market and integrated into space systems. (CSA)