Circularly Polarized Homogeneous Lens Antenna System Providing Multibeam Radiation Pattern for HAPS
Résumé
In this paper, a 30 GHz multibeam antenna design is described that has been developed for high-altitude-platform station (HAPS) applications. When mounted on a HAPS at the stationary altitude of 21 km, this antenna provides cellular coverage on the ground. The antenna consists of a dielectric lens, fed by circular waveguides terminated with small horns. Circular polarization was achieved by integrating a polarizer into the waveguide feed. Each beam presents the same radiation pattern due to the symmetry of the lens. The global antenna system was designed and realized. The prototype fulfi lled the initial specifi cations. It showed a directivity of 21 dBi and an impedance bandwidth at 10 dB of 19%. Moreover, an axial ratio lower than 2 dB was achieved within this bandwidth.