Ka-Band Huygens Array with High Realized Aperture Efficiency for 5G Wireless Applications

This paper presents a Ka-band Huygens antenna array with exceptionally high realized aperture efficiency for 5G wireless applications. The basic radiating element is a $1\times 2$ Huygens sub-array realized by two open waveguides and two orthogonally-oriented dipole plates. The dipole plates are connected to the waveguide openings. In this manner, two pairs of Huygens electric and magnetic radiators are formed on the antenna aperture. A reflector with the same size as the radiating aperture is placed below it as a current choke to mitigate the fields scattered from its edges. High aperture efficiency is realized because almost the entire aperture is utilized for the co-polarized radiation. Moreover, an expanded $4\times 8$ array is designed whose elements are excited with the same amplitude and phase by a 1 to 32 waveguide feed network. The -10-dB impedance bandwidth covers 11.3% from 26.4 to 29.55 GHz. Within this bandwidth, the peak realized gain value is 22.27 dBi and the peak realized aperture efficiency is 90.4%.