Considerations Regarding the Directivity of Antenna Arrays, Uniformly Distributed and Non-uniformly Illuminated

Abstract

This paper presents the results of the analysis of uniformly distributed but non-uniformly fed antenna arrays in order to reduce the level of the sidelobes of the sum radiation pattern of the array. After a presentation of the general aspects related to the theory of linear weighted antenna arrays, the analysis focuses on some weighting functions expressible by series of complex exponential functions, applied both to linear arrays and to arrays with planar aperture, uniformly distributed: the family functions "cos2 with pedestal", the family of Blackman functions and the Taylor weighting function.In the paper, after the unitary foundation of the mathematical support of the theory of weighted linear arrays, it is extended to weighted planar arrays. This support was then modeled by programs designed to calculate the main parameters of the directivity of the weighted arrays (opening at -3dB of the main lobe of the radiation pattern, the beam broadening factor, the position and level of the sidelobes, the maximum value of the directivity coefficient and the losses in its value related to the unweighted array), as well as the graphic representation of the array's sum radiation patterns. The obtained results highlight the net advantages of using the Taylor weighting function.