A High Isolation Series-Shunt RF MEMS Switch

• Main Authors: Yi Shi, Shi-Xing Jia, Jian Zhu, Yuan-Wei Yu
• Format: Article
• Language: English
• Published: MDPI AG 2009-06-01
• Series: Sensors
• Subjects: series-shunt; RF MEMS switch; metal-contact; electrical model
• Online Access: http://www.mdpi.com/1424-8220/9/6/4455/
• ISSN: 1424-8220

This paper presents a wide band compact high isolation microelectromechanical systems (MEMS) switch implemented on a coplanar waveguide (CPW) with three ohmic switch cells, which is based on the series-shunt switch design. The ohmic switch shows a low intrinsic loss of 0.1 dB and an isolation of 24.8 dB at 6 GHz. The measured average pull-in voltage is 28 V and switching time is 47 µs. In order to shorten design period of the high isolation switch, a structure-based small-signal model for the 3-port ohmic MEMS switch is developed and parameters are extracted from the measured results. Then a high isolation switch has been developed where each 3-port ohmic MEMS switch is closely located. The agreement of the measured and modeled radio frequency (RF) performance demonstrates the validity of the electrical equivalent model. Measurements of the series-shunt switch indicate an outstanding isolation of more than 40 dB and a low insertion loss of 0.35 dB from DC to 12 GHz with total chip size of 1 mm × 1.2 mm.