Reconfigurable bandpass filter structure using an SPDT MEMS switch

A concept for a bandpass reconfigurable filter structure capable of operating a two different passbands is presented. The circuit consists of two edge-coupled-line bandpass filters and a single-pole double throw MEMS switch. The incident signal enters a three-conductor set of coupled lines which feeds the two bandpass filters. The switch selects between the outputs of the two filters and thus a reconfigurable system is obtained. The switch used uses a magnetic actuation system and requires a voltage pulse of less than 4.0 V and consumes a peak transient current of 49 mA. The quiescent current consumption is 0 mA. The two passbands of the system presented here are at 1.8 GHz and 2.2 GHz. The rejection between the bands is about 20 dB. Much better rejection is possible by improving the isolation characteristic of the switch.