Artificial magnetic surface for circularly polarized antennas

In this work, we present a novel approach to the same issue, by using a squared shape FSS. In this case, the AMC does not act as a polarizer since the response to TE and TM mode is the same. Conversely, the improvement in axial ratio (AR) is achieved by suitably exciting the AMC surface, i.e. by applying a properly rotating field obtained by using, as a source, an Archimedean spiral antenna. Measurements have shown a 20 dB increase in the cross polarization discrimination (XPD) with respect to the antenna radiating in free space.