RF MEMS asymmetric capacitive switch with high‐isolation at selected low‐microwave frequency

An asymmetric RF microelectromechanical systems (MEMS) capacitive switch with a novel architecture employing mode switching from a coplanar waveguide (CPW) mode to a coupled slotline (CSL) mode is reported for selected frequency within the 2–10 GHz low microwave frequency range. An additional metal-insulator-metal (MIM) capacitor is introduced on one end of the switch membrane as a tuning capacitor. The signal line of CSL is used as a tuning inductor. These two tuning elements together can improve the isolation of a regular capacitive RF MEMS switch by about 20 dB at the induced additional low resonant frequency ranging from 2 to 10 GHz. The measurements of the fabricated asymmetric switch demonstrated excellent isolation improvements. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 702–706, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22235