Radiation performance of finite polarization-invariant antenna arrays

Abstract

Polarization invariant antenna array feeds are widely used in satellite communication systems where they can be configured to generate either multiple beams or shaped beams. In this paper finite antenna array consisting of conical horns is studied, and various characteristics of this array are investigated.

The algorithm of the program to compute the performance of axially symmetric conical horns and antenna arrays made of them are created using the mode-matching technique and Galerkin’s method. The program allows to calculate generalized scattering matrix of both a separate conical element and an antenna array, taking into account the mutual coupling of modes. The number of array elements as well as the number of modes that can be taken into account on each aperture is limited only by the memory of PC. Recommendations on how to reduce the necessary memory and increase calculation speed are given. The good agreement between theoretical and known experimental characteristics is obtained. Improving of the computational accuracy of antenna arrays radiation prediction is illustrated. The dependencies of mode mutual coupling, crosspolarization levels, angle deviation of the pattern main beam, side lobe levels and scanning angle versus arrays geometrical dimensions are presented.

The antenna array optimization results with respect to the minimum cross-polarization and side lobe levels are presented. The recommendations for a practical application of the obtained theoretical results are formulated.