A combination of SAW-resonators and conventional sensing elements for wireless passive remote sensing

The basic idea of this sensor is to integrate the capacitive or inductive sensing element into the matching network of the Antenna-SAW-Resonator-System. By changing the matching network the resonance frequency is shifted over a certain range. Two SAW-Resonators are used in order to reduce several external disturbing influences of the radio channel. The change of the difference frequency is the output signal of the sensor system. The SAW-Resonator well protected by a packaging works as transmitter and not as sensing element. Concerning the separation of transmitter and sensing element both of them can be optimized separately. Therefore many physical or chemical properties like pressure, acceleration, strain, pollution and others can be measured with this wireless passive sensor system. Solutions for special applications at extreme environmental conditions like rotation, high temperature or similar can be realized with this passive wireless sensor system