Several WAIM schemes have been introduced and used over the years. The earliest techniques involved using thin high-dielectric-constant superstrates in front of an array aperture34 or dielectric slabs adjacent to the array aperture35,36. The above WAIM schemes either improve scanning in one plane at the expense of the others34, or increase the chance of array blindness35,36. These WAIM techniques were also limited to single frequency or narrow bandwidth operations.