Realization and Measurement of Broadside Beam Modulated Metasurface Antennas

Realizations and measurements of broadside-beam circularly polarized anisotropic metasurface antennas are presented. The validity of the design methodology proposed in a previous paper is here experimentally demonstrated by developing a 28-dBi transmitting antenna and a 22-dBi receiving antenna for space-to-ground links at X-band. High polarization purity is obtained by using a simple vertical (i.e., linearly polarized) monopole as feeder, thus providing experimental evidence of the fact that anisotropic surface increases aperture efficiency with respect to isotropic surface implementation. Both the realized antennas are 1.5 mm thick and do not require a beamforming network as they only incorporate the feeding monopole in the same substrate.