A mutation hill climber for thinning of concentric circular antenna arrays

Thinned concentric circular antenna arrays (CCAAs) are crucial in modern wireless communication systems. CCAAs are widely used for efficient communication, directivity, and beamforming capabilities. Nevertheless, CCAAs encounter a challenge of radiation patterns characterised by high sidelobe levels (SLL). Designing thinned CCAAs to surmount this limitation for optimal performance can be complex and challenging. This paper employs a mutation hill climber (MHC) algorithm to optimise the CCAA structure. The goal is to attain an optimal design that balances the number of switched-on elements and reduces the maximum SLL. The performance and efficacy of the MHC are examined using two different cases of thinned CCAA design: two-ring and ten-ring configurations. Simulation results reveal the superiority of the MHC over the latest binary metaheuristic techniques in achieving the lowest maximum SLL and the number of switched-on elements. For the two-ring thinned CCAA, the MHC effectively switched off 50 antenna elements, reducing the maximum SLL by 24.92 dB. Meanwhile, for the ten-ring thinned CCAA, the MHC reduced the number of switched-on antenna elements from 440 to 184, reducing the maximum SLL by 34.09 dB.