Optimization to the Scan Blindness of Vivaldi Array with Metallic T-Shaped Structure

Vivaldi antenna is a good choice for wideband phased arrays because of its wideband and wide beam performance. However, scanning blindness makes Vivaldi arrays unavailable in the part of its operating frequency and scanning volume. The blindness of interest first occurs for broadside scan when H-plane element spacing is greater than λ
₀
/2 and the scan angle increases with frequency increased. In this paper, a metallic T-shaped structure is proposed to eliminate the scan blindness of the array, and elements are positioned in a triangular grid. An 8×5 array with metallic T-shaped structures has been designed, fabricated and tested. The results have proved that the metallic T-shaped structure is an effective method to eliminate this type of scan blindness.