An Innovative Design of Isoflux Scanning Digital Phased Array Based on Completely Shared Subarray Architecture for Geostationary Satellites

In this paper, we propose an innovative spaceborne isoflux scanning digital phased array (ISDPA) design with two-stage digital beamforming (DBF) for geostationary satellites. To achieve isoflux scanning, a novel technique is presented to obtain an isoflux beam for the ISDPA equivalent element using a DBF completely shared subarray architecture and the differential evolution (DE) algorithm. By reutilizing the radiating elements of adjacent subarrays, the radiation aperture and element number are augmented, enhancing the degrees of optimization freedom. To validate the proposed design, a linear ISDPA with 16 DBF completely shared subarrays is optimized and analyzed using two sets of excitation coefficients in different DBF stages. The numerical results demonstrate that the proposed ISDPA can adaptively compensate for space loss variations during beam scanning for geostationary communications with low sidelobes better than −20 dB.