Design of a quasi-chipless harmonic radar sensor for ambient temperature sensing

This paper presents a passive wireless tag for ambient temperature sensing. The tag uses harmonic radio-frequency backscattering to encode and transmit the measured value. The harmonic radar approach is taken due to the advantage of a radar clutter-free Rx signal, which increases the applicability of the tag significantly compared to many other chipless sensors. The harmonic tag is fabricated with planar printed circuit board technology and it uses a harmonic generator based on a single unbiased diode. The tag setup and wireless proof-of-concept measurements with a range of more than 3.25m are presented.