Highly Efficient Wideband mmWave Rectennas for Wireless Power Transfer System with Low-Cost Multi-Node Tracking Capability

An innovative wireless power transfer (WPT) system utilizing millimeter-wave (mmWave) power for multinode charging and tracking is presented in this article. The core concept of the system revolves around the utilization of frequency-dispersive leaky-wave antenna (LWA) transmitters, enabling passive beam scanning in the far field without the need for active phased arrays. However, such a system requires a breakthrough in receiving rectenna design at mmWave frequencies, encompassing a wide frequency bandwidth, wide beamwidth, and high RF-to-dc conversion efficiency beyond 20 GHz. In this work, we introduce a pioneering mmWave rectenna design achieved through the codesign integration of a magnetoelectric (ME) dipole and high-frequency diodes, eliminating the need for complex impedance matching networks at mmWave frequencies. The proposed rectenna operates in the frequency range of 24-34.5 GHz, achieving over 50% RF-to-dc conversion efficiency for input powers exceeding 15 dBm. In addition, the rectenna demonstrates improved gain and beamwidth compared to conventional designs, enabling wide-angle reception of frequency-scanning passively beamformed mmWave signals. A practical demonstration of the proposed system showcases simultaneous wireless charging of three nodes, highlighting its notable advantages in terms of mobility, cost-effectiveness, and simplicity over conventional WPT technologies.