An Ultralow-Profile High-Gain Dual-Band Dual-Circularly Polarized Shared-Aperture Folded Transmitarray With Extremely Simple Structure

In this paper, an ultralow-profile dual-band dual-CP shared aperture folded transmitarray (FTA) is presented and investigated. A dual band multi-functional metasurface (MFMS) consisting of a CP receiving patch and a CP transmitting patch was designed. By independently controlling the reflection and transmission phase distributions of the metasurface, independent control of beams in two frequency bands is achieved. At the same time, by controlling the reflection phase distribution, the incident waves emitted by the feed source will undergo anomalous reflection, which reduces the antenna's profile to 1/6 of the low-frequency focal length. The experimental results are in good agreement with the theoretical estimation. The antenna gains are 27.92 and 28.99 dBic with the aperture efficiency of 34.3% and 20.3% at 20 and 29.8 GHz, respectively. The measured AR<3 dB relative bandwidths are 14.7% and 9.5% for K- and Ka-bands, respectively. The proposed antenna not only features an ultra-low profile but also has the advantages of a simple structure, low cost, high gain, high aperture efficiency both at the low frequency and at the high frequency, and easy integration, which presents great application potential in the field of satellite communication systems with limited volume and space.