Gain Equalized Shared-Aperture Antenna Using Dual-Polarized ZIM for mmWave 5G Base Stations

A shared-aperture antenna with orthogonal pattern diversity is proposed in this letter. Both the ports have high gain and beam integrity for the operational bandwidth 27-30 GHz intended for the future mmWave 5G base stations. The measured mutual coupling is -18 dB at 28 GHz, and the endfire gains for the individual ports are 7-8 dBi in the band of interest. Hence, in order to achieve gain enhancement and equalization between the ports, a dual-polarized zero-index metamaterial is proposed and is strategically loaded with the shared-aperture antenna for simultaneous gain enhancement in both the ports. The measured mutual coupling post-integration is less than -22 dB at 28 GHz. The endfire gains for the orthogonal ports are in the range of 9.2-9.6 dBi and 1 dB gain bandwidth of 35% with an effective radiating volume of 0.09λ
₀
³
. Detailed simulated and measured results are presented.