Dynamic array beamforming by photonic feedback sensor network

Abstract

Many applications, ranging from sonar, radar and space communications, demand for fully active phased arrays. These antennas have several hundreds of radiating elements or proper sub-arrays, and the possibility of their failure strongly increases. These element failures can cause sharp variations in the aperture field across the array aperture, thus increasing both the sidelobes and the ripple level of the far-field radiation patterns. In this paper a photonic sensors network is properly embedded in the large array aperture such to make an easy, realtime control of the system components on site, by measuring the actual electromagnetic field distribution on the aperture. The embedded photonic network provides an estimation of failure/calibration errors of radiating elements of the antenna array and properly compensates them by dynamically minimizing the mismatch between the current pattern and the reference one by acting on the excitation coefficient of the Beam Forming Network. Numerical and experimental results confirm the capability and the effectiveness of the proposed architecture.