Design of APAA with 4 channel digital beamformer for HAPS

This paper presents the design of the experimental model with 4 channel receivers and four linear array cross dipole antennas. A cross dipole microstrip antenna type, which has a simple radiating element to manufacture easily and a feeding structure of a quadrature hybrid to achieve circular polarization, is considered. The model considered is a simplified prototype of more complicated multielement APAA which should be developed for a stratospheric communication system.