Oxide TFT Rectifiers on Flexible Substrates Operating at NFC Frequency Range

This paper presents the experimental characterization of different rectifier circuits using indium–gallium–zinc-oxide thin-film transistor technologies either at NFC or a high frequency range (13.56 MHz) of RFID. These circuits include a single ended rectifier, its differential counterpart, a bridge rectifier, and a cross-coupled full wave rectifier. Diodes were implemented with transistors using conventional processing steps, without requiring short channel devices ( $L =15\,\,\mu \text{m}$ ). Hence, there is no need for either extra masks or processing steps unlike the Schottky diode-based implementation. These circuits were fabricated on a PEN substrate with an annealing temperature not exceeding 180 °C. This paper finds a direct application in flexible low-cost RFID tags since they enable integration of the required electronics to implement tags with the same fabrication steps.