Wideband Millimeter-Wave Phased Arrays and Carrier Aggregation for 5G and Beyond

Mobile and wireless communications are playing an irreplaceable role in our daily life; 5G is highly expected and can be considered as the convergence of mobile and wireless communications. For supporting communication links with increased date-rate between the base station and the user, millimeter-waves (mm-wave) multiple-input–multiple-output (MIMO) will be adopted globally, the 24.25-27.5-GHz band and the 27-29.5-GHz band are now approved worldwide as the standard 5G communication bands [item 1) in the Appendix]. At mm-wave frequencies, phased-array antennas with 32–512 elements are used to increase the antenna directivity so as to overcome the severe path loss. Such arrays improve the link margin and allow for Gbps communications at 50–300 m.