An apply of hybrid GA for array pattern control of quasi-zenithal satellite´s Earth station antenna

The quasi-zenithal satellite (figure-8 satellite) system is a satellite constellation consisting of three or more satellites placed in inclined geosynchronous circular orbits with an identical inclination of around 45 degrees. At any time, at least one of the three satellites is moving near the zenith view from, for example, Japan. The sub-satellite point traces a so called "figure of eight" locus on the ground, elongating in the north-south direction with an arbitrary point on the equator in the center. Dual use of the same frequency can be applied between geostationary satellites and quasi-zenithal satellites in the fixed-satellite service (FSS). The beam antenna at the earth station used in the FSS can separate spatially the signal of the quasi-zenithal satellite from that of geostationary satellites by using its radiation pattern.. A radiation pattern control method for the phased array antenna of the fixed station of a quasi-zenithal satellite is described. We introduce a hybrid genetic algorithm (GA) technique, which is a combination of GA and the descend method.