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

Abstract

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 dual‐polarised 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 (fLr = 0.7 GHz) is created by the square loop, leading to a compact size of about λLr/4 × λLr/4, where λLr is the wavelength in free space at fLr. Another resonance at a higher frequency (fHr = 1.5 GHz) is generated by etching open slots on the ±45°‐polarised dipoles. A combination of the lower‐frequency 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.

Keywords

• broadband antennas
• dipole antennas