Two-Port Five-Band Rectenna for Ultralow Ambient RF Energy Harvesting

A two-port rectenna is proposed to harvest the ambient RF power from five commercial bands, including 1.8, 2.1, 2.4, and 2.65 and 3.5 GHz for GSM, LTE, WLAN, and 5G, respectively. The novel rectenna comprises a hybrid half-wave rectifier and two back-to-back slot antennas. The rectifier consists of a series rectifier branch and a parallel rectifier branch to extend its multiband coverage, only sharing one diode. With this design strategy, its RF-dc power conversion efficiency (PCE) can reach 23.1% at 1.8 GHz, 26.4% at 2.1 GHz, 27.2% at 2.4 GHz, 20.7% at 2.66 GHz, and 19.1% at 3.47 GHz with −20 dBm input power level. Notably, once a five-tone signal is input simultaneously with the identical power level of −20 dBm, the PCE of rectifying circuit can be improved to 43.7%, breaking the existing record to the best of authors' best knowledge. The designed slot antennas can also receive omnidirectional RF power at five corresponding frequencies. The experimental results demonstrate that our proposed rectenna is competitive in band coverage and PCE with ultralow input power, indicating enormous potential for RF energy harvesting and powering sensors, wearables, and other low-power scenarios.