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 0.09λ03. Detailed simulated and measured results are presented.