Dual-Band, Aperture-Shared Transmitarray for Vehicular SatCom Applications

This paper proposes a novel design and the experimental characterization of a dual-band, shared aperture transmitarray operating in dual linear polarization at K/Ka-band. It is based on a 1-bit unit-cell realized using five metal layers and demonstrating low transmission loss (< 2 dB). By combining the polarization rotation method and the stacked patch architecture, the proposed shared aperture transmitarray is able to shape the beam independently in both K- and Ka-bands. A
$40\times 40$
-element prototype has been optimized by using an
ad-hoc
numerical tool and fabricated. The experimental results are in excellent agreement with the numerical and full-wave electromagnetic simulations. This flat lens is illuminated by two standard gain horns with a nominal gain of 10 dBi. They are mounted in orthogonal polarization and located at the same distance from the aperture (110 mm). A peak gain of 27.1 and 29.9 dBi has been achieved, respectively, at 18.7 and 28.5 GHz corresponding to an aperture efficiency of 26.1 and 22.3%. The possibility to steer mechanically the radiation pattern has also been experimentally proven. The proposed antenna system is a low-cost and compact solution for future vehicular broadband SatCom applications.