Multiple Pattern Synthesis in Four-Dimensional Antenna Arrays Using the Quasi-Newton Memetic Optimization Method

The evolution in wireless radio communication systems has fueled the development of array antenna designs toward the direction of inventive, economical, and outcome-driven solutions. This article explored unorthodox techniques for designing array antennas for multiple radiation pattern synthesis by eradicating the required attenuators and phase shifters. An economical alternate design model is proposed with "Time-modulated" antennas capable of scanning and steering the beam electronically. "Time" is employed as a four-dimensional antenna parameter, and hence, the "Time-modulated" antennas are referred to as four-dimensional (4D) antennas. The idea is conceptualized by controlling high-speed switches attached to the antennas in a periodic way to produce the desirable excitation and phase tapering. So, the requirement of costly phase shifters and attenuators is eliminated. This work expanded the idea of "Time-modulation" for synthesizing multiple radiating beams such as monopulse, scanned beams, and shaped beams for multifunction radar systems. An appropriate switch sequence is designed to produce a concurrent sum-difference pattern for monopulse radars. Simultaneous scanning patterns and shaped flat-top patterns are also proposed for multifunction radars. To achieve the goals, two sets of 4D linear arrays are designed and the modulation parameters switch ON time and periods are optimized with a quasi-Newton memetic GA (Genetic algorithm). All the optimal outcomes are reported and also compared with other counterpart outcomes to show the efficacies of the "Time-modulation" concept for the said applications.