High Performance RF-MEMS cantilever switch

This paper presents the design and fabrication of a new cantilever MEMS switch with very high performance for microwave and radiofrequency applications. The beam and the contact mechanism have been optimized in order to guarantee a repeatable and very low resistance contact. In particular the parallel of 7 gold cupped dimples has been utilized in order to obtain a total contact resistance lower than 1 Ohm. A microstrip prototype has been fabricated on a 525 %m high resistivity silicon substrate by using the micromachining process at ITC-irst in Trento, Italy. The manufacturing process has been refined in order to minimize the gradient stress among the different materials constituting the beam conductor. This prevented the beam tip from bending thus leading to a very good agreement between the theoretical and measured actuation voltage, which is around 50V. RF mmeasurements up to 15GHz have been performed showing a switch insertion loss better than 0.1 dB in the entire frequency band.