A circularly polarised multiple input multiple output antenna with single‐sense for sub‐6 GHz 5G applications

Abstract

Abstract In this study, a compact wideband circularly polarised Multiple Input Multiple Output (MIMO) antenna with the two parasitic elements is proposed. The printed monopole antenna for wideband circular polarisation proposed in authors' previous study is used as an antenna element. One‐sided substrate reflector is installed at the back side of the antenna, positioned 0.2λ0 away, to improve the gain. The circularly polarised radiation, deteriorated by the influence of mutual coupling of two antenna elements and reflector, is improved by deploying two parasitic elements on the bottom layer of the antenna's substrate. The antenna's size is 0.99λ0 × 0.32λ0 and the reflector's size is 1.41λ0 × 0.82λ0 (λ0 is the free‐space wavelength at lowest operating frequency). The measured bandwidth of 10 dB impedance with a 3 dB axial ratio is 33.49% from 3.53 to 4.95 GHz, which can be utilised for sub‐6 GHz 5G applications. The simulated and experimental results are compared to validate the antenna characteristics.

Keywords

• 5G mobile communication
• broadband antennas
• monopole antennas