A Dual-Polarized Rectenna with High Efficiency at Low Input Power Density

This paper presents a new 2.45-GHz rectenna with ±° dual polarization for low-power-input microwave power transmission. By utilizing a ±45 ° dual-linearly-polarized antenna element, the rectenna is available for receiving incident power with arbitrary polarization angle, while avoiding 3-dB CP-to-LP polarization loss. In this way, the requirement of the receiving end to the placement angle is greatly liberated. Differential rectifier structure is utilized. The effect of cross connected load of two branches, which create DC voltage with opposite polarities, are studied. An integrated rectenna design is formed, fabricated and measured. Peak power conversion efficiency of 74.76% is found at input power density of 106.19 $\mu$W/cm2 in the measurement. The power conversion efficiency of the rectenna stays higher than 58.4% regardless of the incident angle under the input power density of 67 $\mu$W/cm2.