High-Gain and Low-Loss Dual-Polarized Antenna Array With Reduced Sidelobe Level Based on Gap Waveguide at 28 GHz

In this letter, a 16×16-element dual-polarized antenna array with a reduced sidelobe level is proposed at 28 GHz for fifth-generation (5G) communication systems. The dual linear polarization operation is carried out through cross-shaped waveguide slots and multilayer feeding networks. Low-loss gap waveguide technology and Taylor distribution are applied in the feeding networks. A ridge unequal power divider with flexible power ratio and phase difference is devised and applied in the gap waveguide feeding network to reduce the complexity of unequal power structural design. A prototype of the proposed dual-polarized antenna array is manufactured by milling technology. Measured results show that the realized gains are higher than 28 dBi over the operating frequency band of 27.4-28.6 GHz. Moreover, the sidelobe level is lower than -18.5 dB for the y-direction polarization and -19.5 dB for the x-direction polarization.