Time Reversal Based Broadband Synthesis Method for Arbitrarily Structured Beam-Steering Arrays

We propose a novel broadband beam pattern synthesis method to synthesize arbitrarily structured beam-steering arrays by utilizing time reversal technique. Unlike conventional frequency-domain array synthesis methods, this method achieves array excitation by taking the Fourier Transform of the time reversed version of the transient signals received by antenna elements. Using this method, designers can determine the array excitation over a wide frequency range at once by a single run of time reversal experiment, instead of performing time-consuming multi-objective optimizations of beam pattern cost-functions at each frequency. Furthermore, it does not require explicit measurements of element mutual coupling and platform scattering effects since the time reversal signals have implicitly taken into account those effects. The proposed method is theoretically analyzed with the antenna reciprocity and numerically validated with three dipole arrays of different configurations. The results show that this new method is capable of realizing accurate beam steering over a wide frequency band if the desired steering angle is located in the feasible angular scope of beam scan. The beam patterns with accurate beam steering are successfully achieved over a bandwidth of more than 1.5 GHz for three different dipole arrays, i.e., a typical linear dipole array, a grounded circular dipole array, and a dome-shaped dipole array.