Low-Power, Retrodirective Tunneling RFID Tag Design with Rat-Race Coupler and Reflection Amplifiers

Radio-frequency identification (RFID) technology has helped grow the Internet of Things (IoT) by integrating sensing, localization, and tracking applications. To help increase the read-range of semi-passive RFID tags, this research proposes a preliminary design for a retrodirective, tunneling RFID tag architecture that loads a rat-race coupler with reflection amplifiers made with low-power tunnel diodes. By banking a small amount of power to drive this circuitry
$(\boldsymbol{216} \mu W)$
, a backscattered signal can be boosted by 18 dB and the read range by a factor of around 4 when compared to a traditional passive tag with a short/matched load.