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In this contribution, we propose a quadratic-gradient metasurface dome operating in the near-field region of a dual-polarized phased array able enhancing its grating-lobe-free scanning range without affecting its other characteristics. The dome consists of an array of Huygens unit-cells exhibiting an extremely low insertion loss and a proper phase shift in transmission. The main characteristic of the proposed dome is the quadratic-gradient phase profile, which minimizes the beam divergence in broadside direction, whereas linearly increases the scanning region in off-broadside pointing angles. A proper set of numerical simulations have been performed showing the capability of the proposed dome to enhance the grating lobe free scanning region from -58° to -83°.

Antenna arrays with large interelement spacing are marginally used in practical applications despite their highly directive main lobe. Their disuse is primarily attributed to the onset of grating lobes even for low scanning angles. In this contribution, we propose the design of a gradient metasurface dome able to reduce the grating lobe amplitude of a dual-polarized phased array. The dome consists of an array of Huygens unit-cells exhibiting an extremely low insertion loss and a properly designed phase of the transmission coefficient. The proposed solution is based on the scanning range shifting approach, which exploits the lower grating lobe levels exhibited by the array when radiating towards directions close to the broadside. A proper set of numerical simulations have been performed considering a 1×4 phased linear antenna array covered by a properly designed metasurface dome, showing its capability to significantly reduce the grating lobe amplitude without significantly reducing the performances in the pointing direction.