Challenges of Millimeter-Wave Active Antenna Systems in 5G

With 5G and New Radio (NR) around the corner, utilization of the millimeter wave spectrum for supporting very high data-rate communication has gained a lot of interest. A key technology necessary to utilize this part of the spectrum is active antenna arrays. However, the design of large, active antenna arrays and radio access in the millimeter-wave bands is facing difficulties due to limitations dictated by physics. In this paper, we will overview some of the challenges facing millimeter-wave antenna systems in 5G and NR.