A Compact Planar Multisector Rectenna Array With Full-Wave Rectification for 3-D Uniform Wireless Powering of IoT nodes

Microwave power transfer offers a promising solution for wirelessly charging sensor nodes in Internet-of-Things (IoT) applications. However, conventional rectennas suffer from limited power harvesting area and significant dependence on sensor node orientation and location relative to the transmitter. This article presents a novel planar multisector mirror rectenna array designed for efficient and uniform microwave power transfer to wirelessly charge IoT sensor nodes. The proposed system addresses limited power harvesting challenges by integrating four endfire rectifying antennas (EFRAs) elements surrounding a centrally located bore-sight rectifying antenna (BSRA) element on both sides of the array like a mirror, ensuring orientation-insensitive coverage in both azimuth and elevation planes. The design facilitates direct conjugate matching of the antenna and rectifier circuit, minimizing insertion losses and enabling a compact, fully integrated form factor. This configuration provides isotropic coverage, making it ideal for RF wave-constrained IoT environments. Simulation results indicate that the system achieves a notable RF-dc conversion efficiency, with the maximum efficiency for the two-series combined EFRA elements observed at 64% (measured 60.5%) and a complete system efficiency of 55% at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2240~\Omega $ </tex-math></inline-formula> and 44.76% at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2482~\Omega $ </tex-math></inline-formula> for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta =90^{\circ } $ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\phi =0^{\circ } $ </tex-math></inline-formula> planes, respectively. The space-diverse rectenna system (SDRS) can harvest approximately 1600 mV of open dc voltage, sufficient to recharge and operate low-power IoT sensor nodes. The experimental setup validated these results, demonstrating the system’s potential as a robust solution for wireless power transfer (WPT) in smart environments.