A 5.8 GHz Fully-Tunnel-Diodes-Based 20 μW, 88 mV, and 48 dB-Gain Fully-Passive Backscattering RFID Tag

Backscatter front-ends are generally praised for their sub-μW power consumptions. However, this power consumption ends up being dwarfed by that of its modulating baseband circuitry. Furthermore, they are plagued by short reading ranges. The work reported in this paper demonstrates, for the first time, the use of a combined single-element oscillator/reflection-amplifier architecture. This remarkable system combines two critical features for range extension–the highest reflection-amplification RFID gain of the literature (48 dB) and higher-than-MHz sub-carrier offset frequency–while displaying a power consumption lower than that of any comparable commercial (amplifier-less) oscillator: 20 μW. This is achieved by using a tunnel-diode, whose properties as a baseband-oscillator and a 5.8GHz reflection-amplifier are analyzed, before both are combined. This highly voltage-sensitive system is synergistically associated with a first-of-a-kind self-regulating tunnel diode-based rectifier to propose a fully-tunnel-diodes-based passive RFID design which could enable the future of practical km-range RFIDs.