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Design of Low Profile Transmitarray Antennas with Wide Mechanical Beam Steering at Millimeter-Waves

Vaquero, A. F. ; Teixeira, J. ; Matos, S.A. ; Baena, M. ; Costa, J.R. ; Felício, J. M. ; Fernandes, C. A. ; Fonseca, N.

IEEE Transactions on Antennas and Propagation Vol. 71, Nº 4, pp. 3713 - 3718, April, 2023.

ISSN (print): 0018-926X
ISSN (online): 1558-2221

Scimago Journal Ranking: 2,32 (in 2022)

Digital Object Identifier: 10.1109/TAP.2023.3243796

Abstract
Mechanical beam steering using a single transmitarray (TA) can be a cost-effective solution for a high-gain antenna with wide-angle scanning. Elevation scanning can be achieved by a linear displacement of the feed in the focal plane parallel to the aperture of diameter D. When designing compact terminals with a short focal length F and with high gain, the aberrations caused by this mechanical movement become the main limiting factor for the maximum scanning range. This work presents a novel design method for devising the TA phase correction with an even distribution of these aberrations among all beam directions. A significant improvement in the scanning performance is achieved when compared with the conventional single-focus phase correction approach. To validate the proposed approach, we consider a TA design at the Ka-band (30 GHz) F/D ∼= 0.34. A multifocal TA design was manufactured using 3-D printed unit cells. To highlight the proposed concept, the antenna configuration is stripped to the bare minimum: a perforated dielectric slab with in-plane mechanical movements in front of an open-ended standard waveguide used as feed. This antenna scans up to 50◦, with a gain of 25 dBi at 30 GHz, 2.5 dB of scan loss, SLL <–10, and 1 dB bandwidth of 6.7%