Distributed MEMS transmission lines for tunable filter applications

This paper describes the design and fabrication of a distributed MEMS trans mission line (DMTL), used to realize a transmission-line with a voltage-var iable electrical length for microwave circuits. The DMTL is a coplanar wave guide periodically loaded with continuously-variable MEMS capacitors. A tun able bandpass filter was designed and fabricated on 700 mum thick glass sub strates using three capacitively coupled DMTL sections as variable shunt re sonators. The measured results demonstrate a 3.8% tuning range at 20 GHz wi th 3.6 dB minimum insertion loss. Issues for future improvement are discuss ed. (C) 2001 John Wiley & Sons, Inc.