Design of a micro-mechanical capacitor with microwave functions

The study concerns remote controlled sensors, associating micro-mechanical and microwave data communication functions. A radio link can be used to transmit information from the sensor as well as to provide internal power supply. Applications include Wireless Sensor Networks projects. An important operation is performed through a passive microwave frequency shifter used for retransmission. Two structures of this frequency shifter using silicon membrane micro-mechanical capacitors are described, with further details concerning the optimisation of the dimensions using electro-mechanical modellisation, the problems in technological silicon implantation, and some first experimental results.