Design of Wideband Concentric-Ring Arrays with Three-Dimensional Beam Scanning Based on the Optimization of Array Geometry

Optimization design of wideband concentric-ring arrays for three-dimensional beam scanning with a minimum peak side-lobe level is addressed in this article. To obtain three-dimensional beam scanning with the lowest peak side-lobe level over a wide bandwidth, concentric-ring array geometries, i.e., radius and inter-element spacing of each ring, are optimized. Optimal array geometries are solved via the differential evolution algorithm, and the results are presented for wideband concentric-ring arrays with different scan angles. The peak side-lobe level of the optimal wideband concentric-ring arrays dropped significantly compared to the periodic arrays after geometry optimization was performed. In addition, the comparison with the periodic wideband array shows that not only does the optimal wideband concentric-ring array have a comparable directivity, but the number of elements is also saved.