Antenna Array Synthesis Through Time Modulation

In the last years, there has been a renewed interest towards the use of time‐modulated arrays (TMAs) thanks to the simplicity in reconfiguring the average pattern of the antenna just modifying the on‐off sequence controlling a set of radio‐frequency (RF) switches. TMAs have been originally introduced for the generation of low and ultra‐low sidelobe patterns for radar arrays [1] thus avoiding the implementation of impracticable excitation tapering with high dynamic range ratios. However, they haven’t received a large diffusion because of the power losses due to the generation of harmonic radiation at multiples of the time‐modulation frequency. As a matter of fact, the periodic modulation of the static excitations causes a shift of the radiated power in the sideband radiation (SR) [2] with a consequent reduction of the directivity of the pattern at the carrier frequency.