New antenna technology for 5G wireless communications

What is the fifth generation (5G) wireless communication? Nobody could tell us an exact definition at present. However, some emerging and potential technologies have attracted more and more attention. Of which, massive MIMO and millimeter wave technologies are considered to be the key technologies for 5G wireless communications. Traditionally, the antenna in mobile communication systems is a passive element and generally is separated from the RF transceivers. For massive MIMO, at either lower microwave band or millimeter wave band, the antenna will be seamlessly integrated with RF transceivers and even with RoF or ADC (DAC) and E/O (O/E). Therefore, the antenna for 5G wireless communications will have distinct characteristics compared to traditional antennas. This special issue will focus on the recent research advances in 5G antennas.