Radiofrequency (RF) semiconductor electronics enable military systems that operate in the microwave and millimeter wave frequency bands of 1-100 GHz. The performance of numerous electromagnetic systems could be enhanced by the inclusion of wide bandgap (WBG) microwave and millimeter wave devices, either as power amplifier or receiver elements. The demonstrated power performance has generally been six to ten times that of equivalent gallium arsenide or indium phosphide devices up through 20 GHz, with enhanced dynamic range and improved impedance matching. These characteristics provide an opportunity to significantly reduce the number of modules required for many active aperture antenna systems, hence, cost, while enabling new capabilities for shared apertures. Prior to realization of any WBG system deployment, however considerable development and maturation of WBG materials, devices, and circuits must yet ensue.