Due to their very complicated coupling environment, the design of miniaturized phased-array antenna systems is very challenging. Among other issues, the results of steering the beam over its intended scan range come into play. The driving-point impedances of the antenna elements comprising the array and the associated voltage-standing wave ratios (VSWRs) are a function of the scan angle.
At Pennsylvania State University, a technique utilizing a hybrid particle-swarm-optimization (PSO) method has been introduced for the design optimization of aperiodic linear phased arrays of tightly packed, miniature meander-line dipole elements. Zikri Bayraktar, Douglas H. Werner, and Pingjuan L. Werner started with a fixed grid of reduced length. By employing hybrid PSO, they determined the optimum meander-wire shape on the grid as well as the optimal element spacing for their smaller phased array. Their approach resulted in a smaller aperture area without sacrificing the number of antenna elements found in a full-sized array.
The same number of antenna elements was maintained and tightly packed into a smaller aperture area. The hybrid PSO array could therefore be driven by a lower power level for a given transmit effective radiated power (ERP). The use of meander-line dipole elements within a predetermined grid structure offers a great deal of flexibility, as the elements can be moved along the grid to produce compact, space-filling curves. By taking advantage of this flexibility, the researchers proposed four different array configurations. See "Miniature Meander-Line Dipole Antenna Arrays, Design via an Orthogonal-Array-Initialized Hybrid Particle-Swarm Optimizer," IEEE Antennas And Propagation, June 2011, p. 42.
