Massive Multiple-Input Multiple-Output (mMIMO) is critical to 5G delivering on its promise of a cellular network. While MIMO typically uses two or more transmitters and receivers to send and receive more data at once, mMIMO extends that concept by significantly increasing the number of antennas on a single array. Until now, silicon-based technologies have been widely used for wireless communications. However, LDMOS devices have power density and high-frequency limitations that cannot suitably meet 5G requirements. The emergence of GaN on high-thermal conductivity silicon carbide (SiC) substrate has enabled mMIMO implementation and thus 5G.