A broadband circularly polarized multi‐beam folded transmitarray antenna

摘要

The multi‐beam reflectarray and transmitarray (TA) antennas are new antennas that can have wide angular coverage. However, they are generally of large profiles. To address the issue, this article proposes a folded TA antenna of high gain and low profile that can produce circularly polarized (CP) multi‐beams. It consists of a main‐reflector, a TA, and a linearly polarized (LP) planar feeding array. It reflects an incident electromagnetic wave twice and converts polarization three times. It has a metasurface that carries out the broadband LP‐to‐CP conversion. A prototype is developed with a height of 1.8λ at 13 GHz. The experimental results show that the antenna can achieve a scanning range of ±10°, a peak gain of 22 dBi, and an aperture efficiency of 20.8%. It has a 3‐dB axial ratio bandwidth of 2.2 GHz (or 16.6%), covering 12.1–14.3 GHz. It features a low profile, high gain, low cost, and easy integration with communication systems (e.g., MIMO transceiver systems).