An integrated MIMO antenna design for Sub-6 GHz & millimeter-wave applications with high isolation

Abstract

An integrated Multiple Input Multiple Output (MIMO) antenna system for sub-6 GHz and millimetre-wave frequency bands with high isolation is presented. The antenna system consists of four triple-band monopole and four dual-band dual-function millimetre-wave antennas. The monopoles work at 2.5 GHz (4G LTE), 3.5 GHz (5G), and 5.2 GHz (WLAN) bands. The millimetre-wave antennas operate at 24 GHz and 28 GHz (5G) and work as decoupling structures between monopole antennas to improve isolation in the sub-6 GHz band. The proposed design has high isolation of −22 dB across the whole lower band, while the maximum value of the envelope correlation coefficient is 0.284. The bandwidths of monopole antennas are 1.75 GHz (2.38–4.13 GHz) and 1.08 GHz (5.04–6.12 GHz). The peak realized gain is 3.47 dBi, 2.65 dBi, and 5.64 dBi at 2.5 GHz, 3.5 GHz, and 5.2 GHz, respectively. The bandwidth of millimetre-wave antennas is 7 GHz (22.28–29.28 GHz) with a gain of 8.5 dBi and 11.4 dBi at 24 GHz and 28 GHz, respectively. The design has a simple structure, compact size, high gain, and wide bandwidth, thus suitable for applications including WLAN, 5G communication, and 4G LTE etc.