Adaptive Nulling in Time-Varying Scenarios Through Time-Modulated Linear Arrays

Unlike classical phased arrays, a key feature of time-modulated arrays (TMAs) is the ability to easily reconfigure the radiation pattern just modifying the pulse sequence that modulates the static element excitations. TMAs have proved to be effective systems for the suppression of interferences and undesired signals impinging on the antenna aperture. Such a capability has been evaluated, up to now and to the best of authors' knowledge, only in case of static scenarios with signals coming from fixed directions of arrival. This letter is devoted to investigating TMAs as applied to adaptive nulling when both the number of signals/interferences as well as the signal directions change in time. Toward this purpose, the on-off TMA sequence is optimized with a suitable global optimization technique that requires a limited computational burden and enables real-time reconfigurations. A set of representative results is reported and discussed to assess the potentialities and the effectiveness of the TMA-based adaptive nulling.