Packing a punch

GEM-T is the first missile to harness the power of gallium nitride

GEM-T, a mainstay of the U.S. Army’s Patriot air and missile defense system, is used to defeat aircraft and tactical ballistic and cruise missiles.

GEM-T, a mainstay of the U.S. Army’s Patriot air and missile defense system, is used to defeat aircraft and tactical ballistic and cruise missiles.

There's a powerful substance called gallium nitride working inside many new technologies, from smart light bulbs and quick-charging cellphones to the lasers that read Blu-ray discs.

Also known as GaN, the semiconductor material boosts power in all kinds of devices. One application is the first missile to harness the power of GaN tech: GEM-T, short for the Patriot™ Guidance Enhanced Missile – Tactical Ballistic Missile. But not all GaN is created equal; the version in consumer products doesn’t hold an LED diode to what's in GEM-T. Raytheon has spent more than $300 million developing the latter kind for the defense sector.

GEM-T, a mainstay of the U.S. Army’s Patriot Air and Missile Defense system, is used against aircraft and tactical ballistic and cruise missiles. Now GEM-T is packing a GaN transmitter that never needs to be recertified over the 45-year life of the missile.

“Our GaN is what’s breathing new life into these transmitters,” said Christine Walsh, Raytheon program manager for an international Patriot program. “GEM-T has been the beneficiary of all those years of Raytheon’s work on GaN technology.”

Those years — nearly two decades — have been spent pushing the limits of power and efficiency of GaN in Raytheon’s Department of Defense-accredited Trusted Foundry, where high performance GaN amplifiers are made.

HOW IT WORKS

Transmitters connect the missile with the ground system, allowing it to control the weapon during flight. The GaN version in GEM-T uses solid state instead of the conventional traveling wave tube design, which requires a supply of parts and recertification to match the life of the missile. The new ones with GaN do not.

The new transmitter has the same form, fit and function as the old one. It’s also tough, doesn’t require additional cooling, and is ready to operate within seconds of powering up. That means that the GEM-T with the new GaN transmitter will continue to perform in the most demanding conditions.

According to Jason Rathbone, missile integrated product team lead for the Patriot product line, the tech is ready for the U.S. Army, and is affordable. “Today,” he said, “the legacy transmitters on the current GEM-T missiles need to be periodically rebuilt and recertified, so replacing the old one with the new solid-state transmitter is a smart move.”

PRODUCTION LINES ARE READY

Raytheon is ramping up production of the GEM-T missile under a number of international contracts. The new transmitter, which was designed to allow future innovations, is well on its way to completing its qualification programs and will be tested during an upcoming flight test.

This transmitter technology might also see additional testing in other missiles. The Army has indicated interest in replacing its entire inventory with these types of long-lasting transmitters, which have reduced recurring costs per unit by 36 percent in the GEM-T program.

Radars and missiles are just the beginning, as GaN technology also has the potential to replace any radio frequency application that requires high power and efficiency in a small space. That includes radio data links, active seekers and proximity fuzes. Advancements like the GEM-T transmitter are only the first.

Last Updated: 10/08/2018