Wideband Metasurface Antenna

This effort explored design of metasurface antennas and evaluated their suitability for ultra-wideband applications (2 to 18 GHz). Six unit cell types were characterized. Eigenmode simulations produced frequency vs. phase data for the unit cells, from which impedance vs. gap size data was computed. A holographic design equation was used to generate the metasurface antenna designs. The unit cell simulations revealed that the assumption of single mode operation is a constraint for wideband designs. An 8 by 8 metasurface antenna with a Rogers 3010 dielectric and a design frequency of 10 GHz was fabricated and tested. It had a 1.5:1 SWR bandwidth of 8.06 GHz (6.47 to 14.53 GHz) and a 2:1 SWR bandwidth of 12.09 GHz (5.91 to 18 GHz). The main beam was 30° wide and had a peak gain of 1.8 dBi. The center of the main beam was ΘL = 0° (+Z direction), which resulted in weaker gain as this is the endfire direction from the driven element. Despite that challenge, this antenna demonstrated that metasurface antennas show promise for ultra-wideband applications when high gain is not a requirement