Effect of Locally Flat Distortions in the Radiating Aperture on the Radiation Pattern of a Phased Antenna Array

Abstract

Introduction. Phased antenna arrays (PAA) of large geometric dimensions find wide application in various spacecraft systems. The PAA design assumes the deployment of its sections in outer space to form a plane of the radiating aperture. However, when implementing such a design, locally flat violations of the radiating aperture may occur. In turn, this may lead to distortion of the original amplitude and phase distribution (APD) under the correct antenna deployment. As a result, the shape of the radiation pattern (RP) changes, in particular, its main maximum shifts and the level of side lobes increases. Under these conditions, in order to ensure the formation of a pattern with the given parameters, it is necessary to correct the APD in a PAA.Aim. To develop a method for correcting the APD in a PAA under the known parameters of violations in the radiating aperture geometry.Materials and methods. The method is based on the condition of minimizing the root-mean-square deviation of the RP formed after correction from the original RP in the absence of aperture violations. The basis of the method is the formation of a redefined system of linear algebraic equations (SLAE) connecting the parameters of geometry violations with RP distortions. Each of the SLAE equations corresponds to a certain angular direction in space, in which the condition of coincidence of the original and corrected RP is imposed.Results. A method for correcting the APD in the presence of locally flat violations of the PAA radiating aperture is proposed. Numerical simulation of the relationship between the parameters of violations and the directional characteristics was carried out. The main relations and results of numerical simulation are presented, in particular, the amplitude distributions, as well as the cross sections of the formed RP and the difference of the normalized RP in the presence of errors in the deployment of the PAA web both without and with APD correction.Conclusion. The results obtained show that, in the absence of APD correction in the PAA aperture, the formation of RP with the given parameters cannot be ensured. In particular, there is a shift of the main maximum of the RP and a change in the nature of the envelope of the side lobes. At the same time, APD correction makes it possible to maintain the RP practically unchanged.