Reconstructing a nonminimum phase response from the far-field power pattern of an electromagnetic system

A new technique for reconstructing the nonminimum phase function from magnitude-only data is presented in this paper. The nonminimum phase function is reconstructed by utilizing the fact that the discrete Fourier transform of the far field power pattern is equal to the autocorrelation of the equivalent spatial current distribution on the electromagnetic structure. An all-pass filter representation is also used to reduce the computational load in computing the nonminimum phase function. The solution for the phase is not unique but is up to a linear phase delay between the actual phase function and the phase produced by the current approach. However, we generate a solution which has a spatially causal response, as the antennas are all finite in size. This approach is applied to the synthesis of nonminimum phase functions from the magnitude only antenna pattern. Several examples dealing with single antennas and antenna arrays have been simulated to illustrate the applicability of this approach.