Electrodynamic characteristics of a four-vibrator radiator with a square screen

Abstract

In the framework of the asymptotic theory of the diffraction of an electric dipole field on rectangular screens, a fast algorithm and programs for calculating the directional and polarization characteristics of radiation produced in the far zone by two orthogonal pairs of parallel half-wave vibrators, placed in parallel to an infinitely thin perfectly conducting rectangular screen, are developed. It is shown that, in the case of a square screen at the optimal distance between the vibrators, radiation patterns with axisymmetric main lobes up to the field levels of −12…−16 dB in a sector of observation angles ±45° from the normal to the screen are formed. In the shadow region of the screen, the polarization of the field of cophased pairs of vibrators is transformed from linear to elliptic except for the normal direction and diagonal observation planes. If the phase shift between excitation currents of vertical anf horizontal vibrators is 90°, the screen is square, and distance between vibrators are optimally chosen, the ellipticity coefficient of the polarization ellipse exceeds 0.8 in the sector of angles ±70° from the normal to the screen in the main observation planes. In the forward and backward directions of the normal to the screen plane, the polarization is circular.