Polarization misalignment loss mitigation techniques with prototype validation for drone-enabled wireless power transfer

Polarization misalignment, a critical limitation over looked in existing unmanned aerial vehicle (UAV)-enabled wireless power transfer (WPT) literature, is addressed through a frame work integrating hovering UAV swarm formation, geometric rectenna configuration, and antenna multi-plane polarization availability requirements, all analytically derived, yielding an experimentally validated Huygens' metasurface (HMS) transmit antenna prototype. The proposed full-metal HMS antenna features a non-unit-cell periodic structure that avoids localized resonators, unlike existing HMS designs, and achieves broadband forward scattering through inductive boundary impedances. Consequently, test range measurements of the proposed HMS antenna across four planes separated by 45-degrees confirm nearly equal co polarized (CoP) and cross-polarized (XP) boresight power levels, demonstrating polarization balance not achieved by a prior dual polarized array, HMS antennas, or polarization-reconfigurable designs, while also employing a simple feed, unlike existing designs. Simulations confirm that dual-axis UAV and gimbal-based yaw stabilization enable progressive yaw control of HMS antennas, achieving nearly 100% geometric polarization alignment and yielding a relative reduction in the proposed hovering UAV swarm size of approximately 75%. Furthermore, increasing the number of rectenna array reception elements from 2 to 16 yields a further relative reduction in the proposed UAV swarm size of nearly 87.4%, demonstrating that geometric polarization alignment depends on both the transmit antenna and rectenna configurations. Overall, the antenna's robust full-metal design ensures high-power handling and reliable UAV deployment in harsh environments.