Active Beamsteerable Digital Metasurface Lens Antenna for Millimeter-Wave Applications

A high-gain phase-graded digital metasurface lens (PG-DMSL) antenna enabled with active beamsteering based on reconfigurable feed source for millimeter-wave applications is proposed. An end loaded cross-dipole slotted structure is proposed as a transmission-type unit cell (UC). The designed UC achieves a transmission magnitude better than −3 dB with 2-bit phase tuning at 28 GHz. Furthermore, PG-DMSL is devised by arranging four sets of the proposed UCs in an array of 25 × 25 resulting in an aperture size of 7λ0× 7λ0and a thickness of 0.23λ0. On switching the states of the three p-i-n diodes, the radiating feed antennas kept beneath the designed PG-DMSL at an optimum focal distance of 20 mm can be switched resulting in steered beams along 0° and ±30°. The proposed design is experimentally validated showing a measured broadside gain of 19 dBi with an augmented gain of 14.9 dB and a scan loss of 1 dB.