Coupled Feed Mechanically Rotating Antenna for Unmanned Aerial Vehicle Direction-Finding

This paper proposes a coupled feed mechanically rotating antenna for unmanned aerial vehicle (UAV) direction-finding (DF). The propeller blades themselves are designed as a half-wave dipole., with a cross-shaped feed component mounted on the blade safety cover. Capacitive coupling is used to feed the dipole without direct contact. When the propeller rotates., the mechanical movement guides the figure-eight radiation pattern to rotate within the horizontal plane, allowing a single-channel amplitude receiver to achieve direction-of-arrival (DOA) estimation. Simulation and numerical experiment results demonstrate that this antenna maintains DF accuracy comparable to traditional mechanically rotating dipoles, while offering the advantages of lower cost and reduced payload. Compared to the direct feeding method for rotating propeller antenna, the coupled feeding approach better fits the mechanical and dynamic structure of the UAV and offers higher efficiency and achievable gain.