Synthesis of time-modulated frequency diverse arrays for short-range multi-focusing

The synthesis of frequency diverse arrays (FDAs) able to achieve time-invariant spatial focusing performance in the short-range is addressed. Two time-modulated optimized frequency offset schemes are presented that allow focusing the energy at a single target location and multiple target locations, respectively. A set of numerical examples is reported and discussed to validate the effectiveness of the proposed solutions also in comparison with the already proposed FDA design approaches.