Chiral slab polarization transformer for aperture antennas

The cross polarization of large aperture antennas can be eliminated by a chiral slab transformer in front of the aperture to obtain a more efficient field pattern. The inhomogeneous chirality distribution required can easily be achieved by using a mixture of right- and left-hand helices so that the total density of the helices is constant inside the slab. Reflection from the slab can be eliminated by a proper design.