Polarization performance of log-periodic antennas on top of different types of ground plane; the SKA-low instrument case

In this paper we discuss the polarimetric performance of log-periodic antennas for low frequency radio astronomy applications. We do this in the framework of the SKA-low instrument, the largest aperture array at meter and centimeter wavelengths to be built by the end of this decade. When a log-periodic antenna, such as the ones to be used in SKA-low are standing on top of a large metallic ground plane, their polarimetric performance changes with respect to the case of the antenna in free space. We discuss therefore these effects and their dependency on the ground plane conductivity (i.e. metallic ground plane versus lossy ground).