RF-Powered Transceiver With an Energy- and Spectral-Efficient IF-Based Quadrature Backscattering Transmitter

This study introduces a 5.8 GHz RF-powered transceiver that includes a transmitter using an IF-based quadrature backscattering (IFQB) technique. The IFQB transmitter can produce a quadrature modulated signal without active RF circuits, such as PLL, local generation, and local distribution circuits. Thus, the IFQB technique can significantly reduce the power consumption while achieving denser constellations by the quadrature modulation. The RF-powered transceiver consists of the IFQB transmitter, an OOK receiver, and a power management unit (PMU) for RF powering. The transmitter and receiver operate under a 0.6 V power supply provided by the PMU to further reduce the power consumption. We fabricated a prototype RF-powered transceiver using a 65 nm Si CMOS process to confirm the validity of the proposed technique. During the measurements, the transmitter achieved 2.5 Mb/s with a 32-QAM modulation while consuming 113 μW. In addition, a wireless temperature sensing demonstration was conducted using the prototype sensor node with the presented RF-powered transceiver.