Inductively-loaded RF MEMS reconfigurable filters

Abstract

This article presents an inductively loaded radio frequency (RF) microelectromechanical systems (MEMS) reconfigurable filter with spurious suppression implemented using packaged metal-contact switches. Both simulation and measurement results show a two-state, two-pole 5% filter with a tuning range of 17% from 1.06 GHz to 1.23 GHz, an insertion loss of 1.56–2.28 dB and return loss better than 13 dB over the tuning range. The spurious passband response in both states is suppressed below −20 dB. The unloaded Q of the filter changes from 127 to 75 as the filter is tuned from 1.06 GHz to 1.23 GHz. The design and full-wave simulation of a two-bit RF MEMS tunable filter with inductively loaded resonators and monolithic metal-contact MEMS switches is also presented to prove the capability of applying the inductive-loading technique to multibit reconfigurable filters. The simulation results for a two-bit reconfigurable filter show 2.5 times improvement in the tuning range compared with the two-state reconfigurable filter due to lower parasitics associated with monolithic metal-contact MEMS switches in the filter structure. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.