Cross-Polarization Treatment in Linearly Polarized Vivaldi Array Apertures

This paper examines how cross-polarization can be effectively reduced in two-dimensional array apertures of linearly-polarized Vivaldi antennas. In previous work it was demonstrated how metallic cross walls, positioned orthogonal to the linear Vivaldi antenna elements in a two-dimensional array, reduce cross-polarization significantly - e.g., -15dB levels for 45° diagonal plane scans. This cross-polarization mitigation technique is expanded upon by showing that slices in the metallic cross walls can further reduce cross-polarization, e.g. -25dB levels for 45° diagonal plane scans. For demonstration, an 8×8 single-pol. Vivaldi array comprising 8 rows of 8-element sub-arrays arranged onto a uniform grid with slots between elements is presented. Cross-polarization measurements are compared to infinite array simulations with and without ‘sliced’ metallic cards inserted (orthogonally) into the slots between radiating elements.