Microelectromechanical variable-bandwidth if frequency filters with tunable electrostatical coupling spring

International audienceThis paper describes the theory, design and test of a novel architecture of highly-selective micromechanical filters employing electrostatically coupled resonators with floating or biased coupling electrodes. This original method avoids the use of mechanical coupling springs thus extending the potential of a given process to higher frequencies. It gives also the possibility to implement more complex filter architectures and to tune the coupling factor of resonators. Filters with 2.8 MHz and 10.6 MHz center frequency having tunable relative bandwidths of 0.025-0.17% have been built from pairs of clamped-clamped beam resonators. Special design techniques have been used to reduce parasitic capacitances on the coupling node

Packaged Single Pole Double Thru (SPDT) and True Time Delay Lines (TTDL) Based on RF MEMS Switches

Packaged MEMS devices for RF applications have been modelled, realized and tested. In particular, RF MEMS single ohmic series switches (SPST) have been obtained on silicon high resistivity substrates and they have been integrated in alumina packages to get single-pole-double-thru (SPDT) and true-time-delayline (TTDL) configurations. As a result, TTDLs for wide band operation, designed for the (6-18) GHz band, have been obtained, with predicted insertion losses less than 2 dB up to 14 GHz for the short path and 3 dB for the long path, and delay times in the order of 0.3-0.4 ns for the short path and 0.5-0.6 ns for the long path. The maximum differential delay time is in the order of 0.2 ns

Single-Pole Double-Thru and True Time Delay Lines in Alumina Packaging Based on RF MEMS Switches in Silicon Technology

Packaged MEMS devices for RF applications have been mod- elled, realized and tested. In particular, RF MEMS single ohmic series switches have been obtained on silicon high resistivity substrates and they have been integrated in alumina packages to get single-pole-double-thru (SPDT) and true-time-delay-line (TTDL) configurations. For this purpose, the individual switches have been considered as the building blocks of more complicated structures, and the alumina substrate has been properly tailored in order to get the best electri-cal performances considering all the technological steps necessary for the final hybrid device. Actually, several parameters and processes have been considered for such an optimization, involving the geometry, the wire bonding and the cover to be used. Test structures with technologically actuated switches have been also manufactured in order to have the best reference result for the proposed structures. After that, the same devices have been packaged for the final test. As a result, TTDLs for wide band operation, specifically designed for the (6–18) GHz band, have been obtained, with insertion losses less than 2 dB up to 14 GHz for the short path and 3 dB for the long path (5 dB for the real device), and delay times in the order of 0.3–0.4 ns for the short path and 0.5–0.6 ns for the long path. The maximum differential delay time is in the order of 0.2 ns