Beam-Steering Flat Lens Antenna Based on Multilayer Gradient Index Metamaterials

A low-profile lens antenna based on multilayer gradient index metamaterials (GIMs) is designed and fabricated. The beam steering is achieved by mechanically changing the location of the feed horn. Nonresonant structure is used to construct the GIMs, so the metamaterial can work in broadband with negligible intrinsic loss. Standard printed circuit board techniques are used to fabricate the prototype. The diameter of the prototype is 98 mm, and the thickness is 17 mm. The antenna is designed to work in the Ku-band, with aperture efficiencies up to 74% and 65% at 12.5 and 14.25 GHz, respectively. The antenna gain drops about 2.5 dB when the beam scans to 40°. The sidelobe level is lower than −10 dB within the scanning range. The prototype confirms the feasibility of using metamaterials technology for achieving high-efficiency and broadband beam-steering antenna, which holds great promise for applications in on-the-move satellite communication.