MEMS Switches

Computer Engineering electronics Engineering Civil Engineering

A surface micro machined capacitive switch has been designed and fabricated on a glass substrate. The switch is constructed of a thin metallic membrane crossing over an electroplated coplanar wave-guide transmission line. The electrostatic actuation is utilized as the switching mechanism. The actuation voltage is around 50V. The switch showed low insertion loss of 0.1 dB at 10 GHz and 0.4 dB at 25 dB, and isolation of 15dB at 20GHz. This device offers a potential application in telecommunication, phase antenna array system, etc. Compound solid state switches such as GaAs MESFETs and PIN diodes are widely used in microwave and millimeter wave integrated circuits (MMICs) for telecommunications applications including signal routing, impedance matching networks, and adjustable gain amplifiers. However, these solid-state switches have a large insertion loss (typically 1 dB) in the on state and poor electrical isolation in the off state. The recent developments of micro-electro-mechanical systems (MEMS) have been continuously providing new and improved paradigms in the field of microwave applications. Different configured micro machined miniature switches have been reported. Among these switches, capacitive membrane microwave switching devices present lower insertion loss, higher isolation, better nonlinearity and zero static power consumption. In this presentation, we describe the design, fabrication and performance of a surface micro machined capacitive microwave switch on glass substrate using electroplating techniques. loading..