A coupled-mode filter structure for wireless transceiver-sensors using reactive loads

The possibility to remotely control impedance changes using resonant devices operating in the 434-MHz-centered Industry-Scientific-Medical (ISM) is demonstrated in this paper. The proposed principle is based on acoustically coupled modes in compact Surface Acoustic Wave (SAW) structures in which one port is connected to the variable load, the other being connected to a Radio-Frequency (RF) antenna for wireless interrogation purpose. The operation of the proposed principle is illustrated using a longitudinally-coupled resonator filter on quartz for “On-Off” switch remote control. Other sensor architecture are discussed as a conclusion of this work.