Highly integrable paper-based harmonic transponder for low power and long range IoT applications

In this letter, the design and performance analysis of a harmonic planar transponder on paper, which conjugates compactness and scalability, are presented. The tag, targeted for a fundamental frequency of 1.2 GHz, is based on a frequency doubler with a single lumped component (a low-barrier Schottky diode) and a system of nested tapered annular slot antennas. Both antennas, orthogonally placed, feature a maximum gain around 3 dBi. The frequency doubler is optimized for power levels in the order of -13 dBm, where it achieves a conversion loss of 15.7 dB. A complete prototype has been tested in a wireless indoor experiment, demonstrating a coverage of at least 4 meters, insensitive to tag-to-reader rotations (transmitter EIRP 16 dBm).