A Multi-Beam Transmitarray Antenna with Scanning Loss Improvement

In this paper, a multi-beam transmitarray antenna (TA) is proposed, which has the characteristics of polarization conversion and low scanning loss. The TA element adopts double-layer structure, and the two layers are orthogonal to each other. This element has selective properties for linearly polarized waves and can convert incident linear polarized (LP) waves into orthogonally LP waves. Seven waveguide antennas are used as feed antennas, and beam scanning can be realized by switching feed antennas. In addition, an optimization method of phase distribution is proposed to improve the scanning loss. And the method is verified by simulation. The maximum gain of TA is 21.79 dBi at 10 GHz, which can realize beam scanning of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 25^{\circ}$</tex> in the elevation plane, and the scanning loss is not more than 1.6dB.