Reconfigurable Thinning for the Adaptive Control of Linear Arrays

Dealing with the adaptive nulling of the array radiation pattern, two reconfigurable thinning strategies are presented and assessed. An easily-reconfigurable and low-complexity antenna architecture is considered where a set of radio-frequency switches is exploited to either connect or disconnect the array elements for controlling the radiation pattern and generating deep nulls along the directions-of-arrival of the undesired signals. By defining through a genetic algorithm-based optimization the on/off status of the switches to maximize the signal-to-interference-plus-noise ratio at the antenna output, two different formulations are discussed. The first one does not constrain the number of active elements, while the other forces the solution to satisfy a fixed-directivity criterion also in correspondence with a time-varying interference scenario. The performances of the proposed approaches are assessed in both static and time-varying scenarios where single and multiple interfering signals impinge on the array from different angular directions.