A W-Band Large FOV Scanning Metalens Antenna Based on Coaxial Ring Aperture Unit

A larger-field-of-view W-band metalens antenna for passive millimeter wave imaging technology has been proposed. The metalens consists of
$\mathbf{12}\times \mathbf{12}$
coaxial ring aperture units (eRAUs) and the size of metalens is
$\mathbf{5.644}\boldsymbol{\lambda}_{\mathbf{0}} \times \mathbf{5.64}\boldsymbol{\lambda}_{\mathbf{0}}$
. The metalens is fed by a corrugated horn antenna at 94GHz. The proposed metalens achieves a beam scanning range of 0~30° and peak gain can reach 23.07dBi at 94GHz, the 3dB gain bandwidth is 16GHz (86-94GHz). Within the entire beam coverage, the gain float is lower than 0.84dB, and the maximum 3dB beamwidth change is 1.63° at 94GHz. Furthermore, the sidelobe level is lower than -19.81dB and the highest radiation efficiency of the matalens reaches 50.73%.