Exploitation of RF-MEMS switches for the design of broadband modulated scattering technique wireless sensors

The use of RF-MEMS switches for the design of broadband modulated scattering techniques (MST) wireless sensors has been investigated in this work. In an MST sensor the antenna is loaded with different resistive loads to produce a modulation in the backscattered field by means of an electronic switch. At microwave frequency bands the RF switches are quite expensive moreover they are quite narrowband. The narrowband behaviour of MST sensors is one of their major drawbacks. The adoption of RF-MEMS microwave switches, could be a good opportunity to overcome this problem. In particular MEMS switches are able to good performances up to 110GHz with a reduced dimension and complexity, as well. In this work a MST sensor prototype based on MEMS switches and able to work in the whole X band from 8 GHz to 12 GHz has been designed, fabricated and experimentally assessed. The obtained results are quite good and they demonstrate the feasibility of such kind of sensors. In particular the MEMS switches demonstrate that they could play a key role for the design of millimetric and sub millimetric frequencies bands MST sensors, where the standard microwave switches technologies can't operate.