High-Efficiency and Compact RF Rectifier Design for Wireless Sensors in Extreme Environments

Radio frequency (RF) energy harvesting garners significant attention for prolonging the lifespan of wireless sensor networks (WSNs). However, its deployment in extreme environments is constrained by low RF power. Therefore, to guarantee the sustained functionality of WSNs, it is imperative to enhance rectification efficiency at low incident power. This paper proposes a novel rectifier with highly efficient operation at low incident power. The rectifier comprises a T-type power divider with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${CLC}\pi$</tex-math></inline-formula> network and two identical sub-rectifiers. Utilizing this, the reflected power from the sub-rectifiers can be re-injected into the rectifier so that it can be reused, and the rectification efficiency can be improved. Theoretical analysis and performance comparison are carried out. The experimental results indicate that the proposed rectifier is capable of achieving high rectification efficiency at low incident power. The recorded efficiency remains notably above 10% at an incident power of -<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$30dBm$</tex-math></inline-formula>, with an operating bandwidth of up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$320MHz$</tex-math></inline-formula>.