Radiation Pattern Synthesis of Smart Fourth Dimensional (4D) Antenna Arrays Using Optimal Pulse Splitting Method

Designing and developing smart antennas with adaptive radiation characteristics is an integral part for present-day communication systems. The versatile capabilities of Time-modulated fourth-dimensional (4D) antenna arrays can provide that crucial adaptability if properly designed. This work discusses an effective analysis of 4D antenna arrays to achieve less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands. The 4D arrays offer an additional benefit over standard arrays in the sense that the requisite amplitude tapering to lower the undesired radiations can be accomplished by controlling only the switch ON times of the radiating elements instead of using attenuators. The idea of splitting pulses by keeping the total switch ON durations constant, is exploited here as an additional degree of freedom for beamforming of all the radiation patterns. The unwanted radiations in terms of sidelobes as well as sideband radiations at the fundamental and harmonic frequencies, respectively are simultaneously minimized to improve the radiation efficiencies of the 4D array. To address the conflicting aims for the synthesis of radiation patterns, a wavelet-mutation based heuristic method is also proposed. The multi-objective problem in hand is modulated in to a single objective cost function as minimization problem. The proposed outcomes are compared with other works.