Northrop Grumman [NOC] said on Jan. 11 that it is developing the AN/APG-85 Active Electronically Scanned Array (AESA) radar for Lot 17 and beyond of the Lockheed Martin

[LMT] F-35 fighter.

The APG-85 will be the follow-on to the F-35’s current AN/APG-81 AESA radar, built by Northrop Grumman at its Linthicum Heights, Md., plant.

“The capability of the F-35 advanced radar will enhance the DoD’s ability to execute the National Defense Strategy in the future,” the F-35 Joint Program Office (JPO) said in a Jan. 11 response to questions. “Therefore, certain information will continue to be protected by enhanced security measures due to the critical nature of the technology.”

The F-35 JPO did not reveal what features the APG-85 will have that the APG-81 does not, but said that the APG-85 “is modernized to be the top-of-the-line radar available today, ensuring American dominance in the air.”

The F-35 program declined to release funding and contract details for the APG-85. The F-35 JPO has said that the APG-81 has 1,676 Gallium Nitride (GaN) transmit/receive (T/R) modules, but the F-35 JPO and Northrop Grumman declined to say whether the APG-85 will also be a Gallium Nitride-based radar.

We do not disclose technical information on operational capabilities,the F-35 JPO said on Jan. 11.

Last year, in a combined Orange Flag and Black Flag exercise, the U.S. Air Force tested emissions control (EMCON) tactics for the service’s F-35As to allow them to remain at stand-off range while detecting threats through passive Electronic Support Measures, rather than through the APG-81 and other electronic signatures (Defense Daily, March 19, 2021).

Retired Air Force Lt. Col. Mike “Pako” Benitez, the former director of staff for the Air Force 53rd Wing, the service’s primary operational test wing, suggested in the latest edition of his newsletter, The Merge, that the APG-85 is likely a GaN radar.

“GaN chips have three times the bandgap width as a silicon chip, meaning they can move more electrons with less energy loss (i.e. heat), and they can sustain higher temperatures than silicon,” he wrote.

The benefits of GaN radars include “increased detection range (read: small and stealth targets); smaller package (read: mobile and multi-domain use cases); [and] wider range of operating frequencies (non-traditional spectrum operations, harder to jam, etc),” Benitez wrote.

Northrop Grumman, Lockheed Martin, and Raytheon Technologies [RTX] have invested funds in GaN radars. Raytheon is ahead in that race, Benitez wrote, and over the last decade Raytheon has “invested hundreds of millions of dollars into developing their own DoD-accredited GaN chip foundry.”

Last July, the U.S. Army awarded Raytheon a $354 million contract for additional prototypes of the new Lower Tier Air and Missile Defense Sensor (LTAMDS) radar, which is to replace the Patriot defense system’s current radar. (Defense Daily, July 13). In October, 2019, Raytheon beat Northrop Grumman and Lockheed Martin to win LTAMDS, a 360 degree AESA radar based on GaN that Raytheon said it has been developing over the last 20 years.

Northrop Grumman “might be a bit behind [in GaN radars], but they aren’t asleep at the wheel,” per Benitez. “They are currently delivering GaN-based AESA radars to the Marine Corps for its AN/TPS-80 Ground/Air Task-Oriented Radar (GATOR).”

“GaN is going to quickly disrupt the way militaries fight and maneuver throughout the frequency spectrum—from stealth to electronic warfare,” Benitez wrote. “As perceived capability advantages instantly vanish it may disrupt entire force structure decisions in the next several years.”