Joint mutual coupling characterization and swarm optimization for efficient base station antenna beamforming

In this work, practical beamforming technique is proposed for improving directional radiation properties of base station antennas operating at 1710-2690MHz. Firstly, we characterize the mutual coupling between antenna elements using Rohde & Schwartz multi-ports network analyzer. And with the active radiation parameters (from High Frequency Simulation Software), the real excitation coefficients of the different array elements´ field are outputted by developing a MATLAB algorithm. Next, we use these excitation coefficients as inputs and then develop a swarm algorithm to compute the optimum phases of the array elements for a given sidelobes level requirement and beam steered angle. Experimental results are provided to confirm the analytical approach and the advantage of using mutual coupling characterization and swarm technique in base station antenna design process. Interestingly, results show that the analytical model approach can help to predict even the statistical performances of the antenna before testing it as minimum gap between analytical and experiment results has been observed.