Dual-Band Antenna Hybridizing Folded Transmitarray and Folded Reflectarray

This communication proposes a dual-band antenna hybridizing a folded reflectarray antenna (FRA) and a folded transmitarray antenna (FTA). First, a polarization-rotation transmitarray is designed based on a new Fabry–Perot (FP)-liked phasing element. Unlike its counterparts, this new FP-liked phasing element twists the polarization of electromagnetic (EM) waves and provides sufficient phase tuning range only in the operating band of FTA. In the meantime, in the band of FRA, the transmitarray acts as the polarizing grid, which reflects one polarization while allowing the orthogonally polarized one to pass without affecting its polarization and phase. Second, a polarization-rotation-ground-integrated (PRGI) reflectarray is designed. The reflectarray collimates the EM wave in the band of FRA and twists its polarization by 90°, forming the folded reflectarray. Meanwhile, it also twists the polarization of the EM wave in the band of FTA. By hybridizing the FTA and FRA sharing the same aperture, the proposed design achieves dual-band high-gain radiation. To the best of our knowledge, this is the first time that the FRA and FTA are combined to form a shared aperture antenna, which inherits the advantages of both FRA and FTA, such as high gain, low profile, and reduced blockage effect of the feed. An antenna prototype is fabricated and measured to verify the idea.