The Weekly Debrief: F/A-50 Pushes Gallium Nitride Radars Into Mainstream

A Phantom Strike radar is shown inside the nose radome of an F/A-50.

Credit: Raytheon

A new kind of active electronically scanned array (AESA) radar has gained a foothold in the combat aircraft market, even as the airborne radar technology rapidly expands in performance and the number of competitors. 

The announced selection on May 18 of the X-band frequency Raytheon Phantom Strike radar for Poland’s bespoke version of the Korea Aerospace Industries F/A-50 light attack fighter will introduce the compact sensor into service in 2025. 

As the F/A-50PL is readying for service, Raytheon already faces competition for a compact AESA on the South Korean aircraft. A week before the Polish selection was confirmed, LIG Nex1, a South Korean defense electronics prime, unveiled the X-band frequency ESR-500A, making it an instant, homegrown favorite to win a retrofit order on domestic F/A-50s.

Dueling AESA options for the F/A-50 show how far the technology has come in a short amount of time. Mikoyan introduced the Zaslon passive electronically scanned array (PESA) on the MiG-31 fighter in 1981, packaging multiple antenna elements with a single transmitter. Japan then introduced the first AESA on a fighter in 2000, with the Mitsubishi Electric J/APG-1 integrated on the Mitsubishi F-2. Unlike the single-beam PESA, the antenna elements in an AESA array are connected to hundreds of transmit/receive modules, with each capable of emitting multiple beams at different frequencies.

Following the F-2’s lead, AESA technology swept across U.S. foreign fighter fleets. The Lockheed Martin F-22 introduced the Northrop Grumman APG-77 in 2005, just as the APG-80  entered service on the UAE’s Lockheed F-16 Block 60s. The Raytheon APG-79 followed on the Boeing F/A-18E/F Super Hornet in 2006, and the Northrop APG-81 became operational on the Lockheed F-35B in 2015. Boeing has upgraded the F-15Es with APG-82 radars, while Northrop’s APG-83 is now standard on Lockheed’s F-16Vs.  

In Europe, the Thales RBE2 radar entered service on the Dassault Rafale in 2013, while the AESA-based European Common Radar System Mk. 0 has been delivered on Kuwait’s Eurofighter Typhoons and Leonardo Raven ES radar is on board the Saab Gripen NG.

The ubiquity of AESA radars has come in defiance of its cost, which, for example, ranges between $3.5 million for the APG-79 and $5.5 million for the APG-82, according to U.S. budget documents. But the technology offers significant improvements, such as being able to detect targets farther away, performing multiple functions nearly simultaneously and seldom needing to be repaired. 

AESA radars from the last generation, however, are less effective on an aircraft as small as an F/A-50. Their gallium arsenide semiconductors demand too much electrical power from the aircraft and produce too much heat—a condition that must be addressed by a bulky liquid cooling system. 

Advances in commercial technology came to the rescue. With consumer electronics lowering the price of gallium nitride (GAN)semiconductors, radar developers can get the same or better performance on a fire control radar while drawing less power and generating lower heat. As a result, LIG’s ESR-500A and Raytheon’s Phantom Strike are advertised as air-cooled AESAs. 

Both manufacturers advertise their radars for the F/A-50 as weighing less than 150 lb., and Raytheon adds that Phantom Strike will cost half the price of the APG-79 or APG-82. 

Other comparisons between the two systems are difficult to make. LIG, for example, told Aerospace DAILY the ESR-500A features 500 transmit/receive modules. Raytheon currently does not provide a number for the Phantom Strike, although company officials told reporters there would be 906 when the new AESA radar product was unveiled in September 2021. 

The Phantom Strike architecture allows the radar to scale to different applications, including uncrewed aircraft systems, armed helicopters and fighters heavier than an F/A-50. 

The new generation of GAN-powered AESA radars has arrived. As Raytheon delivers Phantom Strike on Poland’s F/A-50PLs in 2025, rival Northrop is scheduled to introduce the APG-85 AESA on the U.S.-operated F-35s.

Steve Trimble

Steve covers military aviation, missiles and space for the Aviation Week Network, based in Washington DC.