A wideband MS to be used as a WAIM layer has been systematically designed and its characteristics were experimentally validated. Its effective material parameters were extracted to show the constancy of ε and μ over the desired, very wide operational band of frequencies. The optimized MS was used as a superstrate over a TCAA of simple printed dipoles to reduce the impedance mismatch of the system to its source when the array is scanning. It was shown that the MS provides improved scanning along the E and D planes over its wide bandwidth without the use of bulky isotropic dielectrics or multi-layered structures. Furthermore, it maintained the scanning performance in the H plane. An MS-TCAA prototype integrated with a realistic feed network will be reported in the near future.