Circularly polarized global navigation satellite systems metasurface antennas in sub-wavelength metallic cavities
Résumé
Two metasurface-inspired antennas embedded in a metallic cavity are introduced here. They are 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. The first one is only 60 x 60 x 20 mm(3) (0.23 and lambda;(1) x 0.23 and lambda;(1) x 0.08 and lambda;(1) at the frequency of 1164 MHz) and presents a dual-band behavior, covering both the lower and upper global navigation satellite systems (GNSS) bands (all GNSS bands are covered). It is fed by four probes and a dedicated circuit, ensuring the phase quadrature between adjacent feeds to achieve circular polarization over these two bands. For the second proposed antenna, circular polarization is achieved using two feed points connected to the radiating aperture of size 50 x 50 x 20 mm(3) (0.26 and lambda;(0) x 0.26 and lambda;(0) x 0.10 and lambda;(0) at the frequency of 1559 MHz). It covers the E1, L1, B1, and G1 GNSS bands. The numerical results are successfully validated by measurements.