Low SLL enhanced gain proximity coupled linear antenna array for 5G wireless communications

Abstract

This manuscript presents a proximity-fed linear seven-element array antenna with significantly suppressed cross-polarization level for fifth generation (5G) wireless communications. The proposed structure uses a Chebyshev form of power distribution to couple the non-uniform radiating elements. Generally, a conventional series-fed array with identical and similar number of elements provides a minimum sidelobe level (SLL) of 13.5 dB and a gain up to 14.51 dBi (maximum). However, the proposed array provides SLL lower than −21.11 dB and a gain of 15.54 dBi at 28 GHz. Moreover, measured cross-pol discrimination is observed to be greater than 36 dB in elevation plane and in the azimuth plane as well. The proposed antenna array includes seven rectangular patches of varying widths on the upper substrate and is fed through proximity coupling using slit-loaded segmented feed lines on the lower substrate. The developed array antenna exhibits a 5.82 % fractional bandwidth from 26.52 to 28.11 GHz with a radiation efficiency of 91 %. Experimental and simulation results of vital antenna parameters are in close agreement. The overall radiation behavior of the proposed antenna array is found to be superior when compared with the other state of the art approaches, as shown in a comprehensive comparison table.