Direction-of-Arrival Ambiguities Mitigation in Multibeam Leaky-Wave Antennas

The inherent frequency beam scanning behavior of leaky-wave antennas (LWA) enables estimating directions of arrival (DoA) with a reduced complexity with respect to antenna-array-based DoA estimation. It has been shown recently that making use of multiple fast Floquet harmonics in periodic LWA can drastically reduce the frequency bandwidth required to scan a large angular field of view. However, with this multibeam operation, the columns of the LWA response matrix are not linearly independent which gives rise to ambiguities, i.e., spurious peaks in the MUSIC pseudo spectrum, in the DoA estimation. Indeed, if the number of snapshots and/or SNR is not sufficiently high, DoA ambiguities arise which leads to false detection. To tackle this issue, this paper investigates an approach to make use of signals received by both ports of a 1-D LWA in order to effectively mitigate those ambiguities.