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The efficiency of a rectenna varies under the influences of receiving polarization tilt angle, operating frequency, input power, and load value in different applications. Yet, no reported rectenna can realize stable efficiency when all these factors vary within a wide range. To solve this problem, an all-polarized rectenna is proposed in this article, composed of a dual-input rectifier and a dual-polarized (DP) antenna. By introducing a novel six-port coupler, the rectifier maintains stable efficiency at wideband, wide input power, and dc load ranges. Moreover, the efficiency of the rectifier keeps stable when the antenna receives power at different polarization tilt angles. Accordingly, a DP antenna with extended bandwidth and 3-dB beamwidth is implemented. Finally, the rectenna is formed. The prototype can maintain beyond 70% of the peak efficiency from 1.7 to 2.5 GHz. At a power density as low as 1 μW/cm2, efficiency can reach 24.4%. Furtherly, the rectenna is demonstrated by forming a battery-less digital clock. The clock can be powered wirelessly by a WiFi router or cellular base station with maximum distances of 1 or 70 m respectively. Besides, the clock can successfully function under significant transmitting-direction deviation or polarization misalignment between the power source and the rectenna. [ABSTRACT FROM AUTHOR]

An RF–DC rectifier is an important part in a wireless power transfer system. Diode-based rectifiers are widely used in low-power harvesting scenarios, and for high power, a transistor based on the time-reversal duality was proposed. This paper presents a high-efficiency self-synchronous RF–DC rectifier based on a waveform-guided design method and an improved rectification model of a commercial GaN device. The main contributions of this paper are that (1) an improved transistor model with correct reverse bias is built for accurate rectifier simulation, and (2) a new design method of self-synchronous RF–DC rectifier is proposed: as soon as the operating mode of the rectifier, input power, and DC load are set, matching and coupling network can be calculated directly based on waveform-guided method, thus design and adjustment process of a conventional power amplifier (PA) due to the duality between a PA and a rectifier would no longer be required. A 5.8 GHz self-synchronous RF–DC rectifier is designed for validation, and the optimum RF–DC conversion efficiency is 68% with 12 W input power as well as 19.9 V output DC potential with 50 Ω load resistance. The proposed rectifier is suitable for high input power rectification applications of wireless power transfer. [ABSTRACT FROM AUTHOR]