Improvement in the design of randomly spaced linear antenna arrays in terms of peak side lobe level

Abstract

An efficient technique for the synthesis of randomly spaced linear antenna (RSLA) array with constraints of spacing between the element and their amplitude excitation coefficient is presented in this paper. The main aim is to obtain best suitable arrangement of randomly spaced element with uniform amplitude excitation on the aperture of RSLA array corresponding to lowest possible peak side lobe level (PSLL). The determination of said arrangement is done by employing Particle Swarm Optimization (PSO) technique. The usefulness of proposed method is validated by considering an example of a 24-element linear array with random inter-element spacings between 0.5λ-1.5λ. This array is numerically studied and results are compared against the equally spaced linear antenna (ESLA) array and further with published articles with similar design cases. It is further aimed that the minimum distance among the elements does not have significant effect on the radiation pattern due to mutual coupling of adjacent elements. This is researched by conducting comprehensive electromagnetic (EM) simulation study with an M-shaped radiating patch element using CST microwave studio software. The EM simulation results of the proposed RSLA array are compared with those of numerical computed and published ones. The obtained results confirm that the proposed algorithm is able to attain better PSLL and valid to design RSLA arrays for practical applications.