Modeling and design of a plasma-based transmit-array with beam scanning capabilities

This work presents the proof of concept of a novel plasma-based transmit-array antenna with beam scanning capabilities. The transmit-array operates above the GHz (precisely at 1.6 GHz) and is capable of steering its main lobe up to thirty degrees. A metallic half-wave dipole is used as the active element of the transmit-array, while twenty-five cylindrical plasma discharges are adopted to steer the beam of the antenna simply by turning them on or off. These passive elements are geometrically displaced in a triangular lattice. A customized two-steps optimization strategy is used to choose the best geometrical parameters of the array and to select the subset of plasma discharges that maximizes the gain of the antenna for each desired scanning angle. Towards this aim, a particle swarm optimization is first used to optimize the geometrical parameters of the array, and then a genetic algorithm is adopted to select the optimal subset of plasma discharges that need to be turned on to scan the beam towards different directions. The designed transmit-array was modeled in CST Microwave Studio, using realistic plasma parameters extrapolated from measurements of a fabricated plasma discharge prototype.