Rectifying surface with optimal RF‐to‐DC efficiency insensitive to polarisation collimation.

A rectifying surface for energy harvesting with optimal RF‐to‐DC efficiency insensitive to polarisation collimation is presented based on metasurface and branch‐line coupler. The metasurface captures two orthogonal components of incident wave by two separate loads with high efficiency. A 90° branch‐line coupler is introduced to redistribute two polarisation‐dependent components into two invariant equipower outputs, aiming to preserve continuous impedance‐matching between metasurface and rectifiers for maximised conversion efficiency. The proposed rectifying surface has been fabricated and measured. The measured fluctuation ranges of capture and conversion efficiency are smaller than 2 and 0.5%, respectively, agreeing well with authors' prediction. They expect a wide range of applications to emerge from this novel concept in the future. [ABSTRACT FROM AUTHOR]