Original identification technique of passive EM sensors using loaded transmission delay lines

This paper presents a proof of concept of an original identification technique of passive EM sensor cells. Previous works published by the authors have shown the feasibility of high sensitivity passive sensor Microsystems based on the electromagnetic transduction principle. More, other works, published by the same authors, have demonstrated the feasibility of a wireless interrogation technique of such passive measurement units. This interrogation technique is based on the measurement of the Radar Cross Section (RCS) level of the system composed of the sensor connected to an antenna. In this communication and for the identification purpose, a smart solution combining the sensor cell and a loaded transmission delay line is proposed. The length of the transmission delay line attributes unique identifier to the EM sensor cell. As it will be shown, the measured Beat signal Level spectrum, obtained by using an FMCW Radar reader, is composed of a two parts: one part related to the structural mode (which gives information about the antenna position) and a second part composed of the antenna mode (which gives us information dealing with the sensor measured value and the sensor identification in case of multiple sensor configuration).