Analysis of the radiation characteristics of an ultra-large array antenna consisting of the element apertures for space use [solar power satellite]

A solar power satellite (SPS) which transmits solar power generated in space via microwaves to the ground is being investigated as a new energy technology. The transmitting antenna of the SPS in a geostationary orbit needs an ultra-large antenna about 1 km in diameter. Such an antenna is constructed with many element apertures, because of advantages in transportation and construction of antenna parts. The small antenna is also investigated as an array element. This paper describes the radiation characteristics of the ultra-large antenna which is composed of hexagonal element apertures with a diameter of about 10 m. First, we analyze the element pattern, then we derive the equation of the array factor of the ultra-large array. The radiation characteristics of the total array antenna are analyzed from the field distribution on the element aperture and the total array. The distributions on the array are assumed to be uniform or Gaussian.