Tunable band-stop filter based on single RF MEMS capacitive shunt switch with meander arm inductance

This paper presents a novel high-frequency tunable band-stop filter concept based on a single MEMS capacitive shunt device which uses meander arm anchoring inductors and with a total size of 300 x 600 mu m. Tuning ranges of the central frequency in the order of 55% are experimentally demonstrated for designed filters operating in the Ku to Ka-band frequencies from 13.7 to 30 GHz and from 16.7 to 37 GHz, respectively. A low transmission loss of 0.44 dB and a rejection level of -20.5 dB at 17 GHz are reported. The outstanding tuning range is achieved due to the simultaneous tuning of the MEMS capacitive switch (with a capacitance ratio > 1.5 thanks to the zipping effect) and the exploitation of the voltage-controlled capacitance coupling between the meander arm inductance and the substrate. An easy extraction parameter method of a simplified model is presented based on the susceptance (imaginary part of the admittance) device measurement which results to be a good figure of merit to characterize RF tunable filters. (C) 2010 Elsevier Ltd. All rights reserved.