Communications devices use microwaves, which are tricky to amplify. Vacuum tube hardware weighing hundreds of kilograms is needed to produce the highest-power signals for military radar. Semiconductor devices made of silicon or gallium arsenide work well for the few-kilometer transmissions required by cell phones, but they have too little power to send signals over long distances. A new microwave amplifier built at General Electric’s Global Research Center in Niskayuna, NY, packs the amplifying power of vacuum tubes into a semiconductor package. GE developed techniques for reducing defects in gallium nitride as it is manufactured; the team also built computer models to design devices that work well despite such defects. The result: gallium nitride devices that provide about seven times the power of other semiconductors at certain microwave-communications frequencies. GE is collaborating with Lockheed Martin to deliver high-power radar for lightweight, unmanned military aircraft in five to ten years.