A New Beamforming Technique for the Synthesis of Uniform Circular Antenna Arrays Using Reduced Number of Antenna Elements

The number of elements reduction in different antenna array configurations such as linear, circular, rectangular, planar, and non-planar is of main concern for several research groups. This minimizes the complexity of the feeding network in static antenna arrays, whereas, in adaptive antenna arrays, it reduces the number of active components. The main issue in the array synthesis is to preserve the radiation pattern with minimum distortion compared to the original pattern. These issues are addressed by many researchers in linear, planar, and concentric circular arrays, but no attempt is made in the synthesis of uniform circular antenna arrays (UCAAs) that have elements distributed on a single circle. This is because the synthesis is almost performed in one plane where the radiation patterns in other planes are not predicted. In this paper, most of the aforementioned challenges are treated; the number of elements is reduced, the radiation pattern has minimum distortion, and the radiation pattern is symmetric in all array orthogonal planes. This is performed by dividing the original UCAA's 3D radiation pattern into a suitable number of 2D plane patterns, each of which is separately synthesized using the specified number of elements. The 2D pattern synthesis process for a particular plane is confined to estimating a new set of non-uniform excitation coefficients while keeping the original UCAA's array radius. To construct the final set of synthesized excitation coefficients for the 3D array pattern synthesis, we aggregate all of the estimated sets of excitation coefficients and take the average. To verify the efficacy of the proposed technique, the original and synthesized arrays are realized using the CST Microwave Studio using lambda/2 dipole elements. The results indicated that substantially matched patterns were obtained. Furthermore, the coupling between the synthesized array elements is decreased, which enhances the radiation efficiency and realized array gain.