Evaluation of the polarization performance of a cone-shaped antenna array

Abstract

Conformal antenna arrays are used in various applications when it is either imposed by the shape of the surface, or required by the radiation pattern specifications. One particularly interesting shape of a conformal array is the truncated cone. It might be used in satellite applications where an iso-flux EIRP profile is required (like for example: E. Vourch et al., “Conformal array antenna for LEO observation platforms,” IEEE AP-S International Symposium, 1998). In that solution the top of a cone-shaped antenna is directed to Earth's nadir direction. The radiating elements are distributed on the cone side surface and are organized into linear subarrays. In order to provide an iso-flux steered beam each subarray is required to have a special spatial directivity profile. A Beam Forming Network composed of phase shifters and Butler-like matrices provides the signals required to steer the beam. Since this is an antenna intended for Low Earth Orbit space applications, circularly polarized radiation is required.