A compact broadband antenna for ultra high frequency and L band on 5G new radio base stations

Abstract

A simple method is proposed for the realisation of compact dual-polarised antennas. The aperture area of a dual-polarised dipole antenna can be reduced by half by surrounding the antenna with a square loop. Based on the method, a broadband compact dualpolarised antenna is developed. The broadband dual-polarised antenna consists of two �45°-polarised dipoles surrounded by a square loop and fed by two orthogonal broadband baluns. A resonance at a sfrequency ( f Lr = 0.7 GHz) is created by the square loop, leading to a compact size of about λ Lr /4 � λ Lr /4, where λ Lr is the wavelength in free space at f Lr . Another resonance at a higher frequency ( f Hr = 1.5 GHz) is generated by etching open slots on the �45°-polarised dipoles. A combination of the lowerfrequency and the higher-frequency resonances results in a broadband operation. Simulation and experimental results show that the compact dual-polarised antenna achieves an impedance bandwidth of 75% (0.69-1.52 GHz) for return loss > 15 dB with stable radiation patterns, which is potential to be used for 5G new radio base-station applications. K E Y W O R D S broadband antennas, dipole antennas | INTRODUCTIONThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.