Conical Direction Finding using Frequency-Scanned Bull's-Eye Leaky-Wave Antennas for UAV Tracking Applications

We demonstrate the application of a Bull's-Eye (BE) leaky-wave antennas (LWA) for enhanced conical direction finding, leveraging its inherent conical-beam frequency-scanning capability. Unlike uniform or quasi-uniform 2D LWAs, such as Fabry-Perot Antennas, the 2D periodic BE-LWA uses a higherorder space harmonic to radiate. This enables the use of both backward- and forward-scanning frequency bands to improve the conical direction-finding performance, when compared to the use of a single scanning band. Also, the BE LWA presents rotational symmetry and thus more stability in the direction finding performance for any azimuthal angle. This is demonstrated with experiments using a printed-circuit BE LWA offering a total scanning operating band from 14 GHz to 32 GHz and covering an elevation field-of-view of 120° with fully-azimuthal symmetry.