13.56 MHz Organic Transistor Based Rectifier Circuits for RFID Tags

Abstract

AbstractOne of the potential application areas for organic and polymers transistors is in radiofrequency identification (RFID) tags. One of the key components of an RFID tag is the front-end rectifier that must rectify a 13.56 MHz AC signal received from a resonant tuned antenna. The rectifier supplies operating power to the tag. Organic transistor circuits have hitherto not operated at this high frequency. We show that by operating pentacene transistors in the non-quasi-static (NQS) regime such operating speeds can be achieved in rectifier circuits. The circuits were fabricated on flexible plastic substrates and employed a solution-cast dielectric. The pentacene mobilities are in the range 0.1-1.5 cm2/V-s. The channel lengths of the transistors are in the range 2-4 μm. Full-wave NQS mode rectifiers were measured to have voltage rectification efficiency in excess of 28% at 14 MHz, demonstrating that such circuits can be used in RFID tags. These circuits operated successfully at speeds up to 20 MHz.