In this letter, a beam scanning Alvarez reflectarray (RA) metasurface with its focal length ( F ) inversely proportional to the phase distribution on the Alvarez RA aperture is presented for ±45 o beam scanning coverage and less than 3-dB gain loss. The beam scanning mechanism is based on mechanically tilting the Alvarez RA panel to the desired direction to steer the beam. Compared to a conventional RA where F is directly proportional to the parabolic phase distribution, the proposed Alvarez RA shows a wider 1-dB and 3-dB gain bandwidth, higher aperture efficiency (AE ) , and wider scanning range with less than 3-dB gain loss. The proposed RA has adopted an Alvarez phase distribution which is a summation of two shifted cubic phase profiles. Pancharatnam- Berry (PB) meta-atoms of sub-wavelength periodicity were utilized to provide the 360 o phase range and to enhance the bandwidth of the RA. An |
