Circularly-Polarized GNSS Metasurface Antenna with Two Feed Points in a Sub-wavelength Metallic Cavity

A metasurface-inspired antenna embedded in a metallic cavity is introduced here. It is expected to be integrated on fast moving platforms enduring harsh accelerations and shocks. The metasurface allows enlarging the antenna bandwidth that is intrinsically reduced for small antennas embedded in sub-wavelength metallic cavities. Circular polarization is achieved using two feed points connected the radiating aperture. The proposed antenna covers the E1, L1, B1 and G1 GNSS bands and exhibits a realized gain larger than 4.4 dBic, a half-power beamwidth of 112° and a cross-polarization level better than −20dB over almost the entire upper hemisphere. The numerical results are successfully validated by measurements.