Low-Profile Dual-Band Switchable Dual-Circularly-Polarized Hybrid Antenna for Satellite Communications

In this paper, we propose a low-profile hybrid antenna for satellite communication, integrating a folded transmitarray and a dual-feed reflectarray. Notably, the proposed antenna can realize dual circular polarization switching in dual frequency bands. Specifically, the hybrid antenna consists of a dual-band transmission metasurface (DBTM), a dual-band reflection metasurface (DBRM), and a feeding layer. The electromagnetic waves emitted by the lower-band feed antenna in the feeding layer are reflected by the DBRM and subsequently converted into plane waves at the DBTM. Meanwhile, the electromagnetic waves emitted by the two upper-band feed antennas undergo phase compensation in the DBRM. By incorporating 3dB hybrid couplers in the feeding layer, the antenna can realize dual-band dual-circular polarization switching by selectively exciting different ports. To validate the design concept, a prototype of the hybrid antenna was fabricated and tested, with a profile height-to-diameter ratio of only 0.36. Besides, the proposed antenna achieves peak gains of 20.1 dBic for left-hand circular polarization (LHCP) and 20.01 dBic for right-hand circular polarization (RHCP) at 20 GHz. At 30 GHz, the peak gain is 22.32 dBic for RHCP and 22.35 dBic for LHCP, respectively. The proposed antenna has the advantages of high integration, low cost, and lightweight. These features make it highly suitable for applications in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K/Ka</i> band satellite communication.