An electromechanical mixer using silicon micromechanical capacitors and radio-frequency functions

In conjunction with a remote-controlled smart-sensors project (Villegas M, Bildstein P and Nicole P 1997 Translateur de frequence micro-ondes pour capteur intelligent autonome Proc. 10eme Journees Nationales Microondes (St Malo, 21-23 May 1997) pp 270-1), this study concerns the validation of a radio-frequency microelectromechanical system combining micromechanical capacitive functions and microwave data communication functions. In this project, we have focused on the back-modulation function used for data re-emission. We decided to develop this function with a microelectromechanical mixer made as a passive microwave frequency shifter using an integrated silicon micromechanical capacitive structure. The principles, together with electromechanical considerations, the technology of the silicon implantation, and some first experimental results are described in this paper. The main interest lies in the characterization of the device: both electrical and mechanical properties are tested in parallel to assist us in improving the system and defining a new micromechanical frequency-translator prototype.