Wideband Low-Profile Folded Transmitarray Antenna for K-Band Application

Abstract

A wideband and low-profile folded transmitarray antenna (FTA) is proposed for K-band application in this paper. To ensure high gain and reduce the profile of antenna system simultaneously, both the transmissive metasurface and reflective metasurface with polarization conversion function are employed to construct multiple reflection paths for near-field electromagnetic waves, and a conventional widebeam open-ended waveguide is adopted as the feed source. The phase compensation of the transmissive surface is optimized using the Genetic Algorithm to reduce the quantization error caused by the state discreteness of the transmission unit, thus widening the gain bandwidth. For the fabricated prototype, the upper transmissive metasurface consists of 27×27 units and the lower reflective metasurface consists of 24×24 units. The antenna profile is 1.5λ0, and the height-to-diameter ratio is only 0.19. Measurement results show that the 3-dB gain bandwidth is 36.4% (18.8–27 GHz) and the peak gain is 23.3 dBi. The proposed FTA is a promising candidate for future wireless communication systems.