What’s inside the F-35’s new radar?

Starting in 2025-2026 with Lot 17, all F-35 variants will get a new radar — the APG-85.

While details are scant, and we won’t speculate on capabilities, we will speculate on what’s powering it.

There is a new(ish) type of semiconductor hitting the streets that is based on Gallium Nitride (GaN). GaN was initially developed in the 1990s to solve a very niche, very non-military problem: colored LEDs — specifically, the blue LED (if you’re too young to remember the 1990s, all LEDs were red back then).

At the same time use of silicon was exploding. After all, it makes for a pretty decent semiconductor, which is why it’s used in 95 percent of all electronics sold worldwide today.

But people soon realized that GaN can do some pretty interesting things that silicon can’t when used as a semiconductor in a computer chip.

So what

An F-35B Lightning II attached to the “Flying Leathernecks” of Marine Fighter Attack Squadron (VMFA) 122 sits on the flight deck of amphibious assault ship USS Tripoli (LHA 7), Jan. 11. (U.S. Navy photo by Chief Petty Officer Brian P. Biller)

GaN chips have three times more bandgap width than a silicon chip, meaning they can move more electrons with less energy loss (i.e. heat), and they can sustain higher temperatures than silicon. Translation: GaN offers these key advantages over silicon:

Higher breakdown strength (5-10X more power, radiation-hardened)
Higher efficiency (lower leakage currents, less heat)
Faster switching speed (wider frequency range)
Smaller transistors for smaller chips (Less size and weight)

Hard to comprehend? Apple offers GaN-based rapid chargers for iPhones (iPhone 12 and later) that are 35% smaller but charge three times faster than normal chargers. Go to Amazon, search “gan charger,” and you’ll see how proliferated GaN has become.

GaN also happens to be very useful in radio frequency devices, like active electronically scanned array (AESA) radars. The benefits of GaN-based radars include:

Increased detection range (read: small and stealth targets)
Smaller package (read: mobile and multi-domain use cases)
Wider range of operating frequencies (non-traditional spectrum operations, harder to jam, etc).

Back to the beginning, we’re pretty sure the F-35’s new radar, the APG-85, is using GaN. Every new AESA radar being developed is now using GaN. If the APG-85 isn’t, you should call your Congressman.

The US GaN radar landscape

Lockheed Martin

The AN/TPQ-53 radar staged for the 130th Field Artillery Brigade’s pre-mobilization training at the Regional Training Center in Salina, Kansas. (Photo by Capt. Patrick Montandon/130th Field Artillery Brigade)

Not well-known for its radars (all of their fighter jets use Northrop gear), LockMart is a player on the ground-based scene.

They secured a contract in 2018 to integrate GaN into the Army’s AN/TPQ-53 counter-fire radar, the first of which was delivered in 2020 and is now in full-rate production.
They are also building the giant GaN-based TPY-4 surveillance radar for the Air Force to replace aging TPS-75s.

Raytheon

Over the past decade, they’ve invested hundreds of millions of dollars into developing their own DoD-accredited GaN chip foundry, and they are the furthest ahead in the GaN-based radar race.

They’ve secured contracts to integrate GaN into its larger-sized line of arrays like the Army’s AN/MPQ-53 (Patriot) and AN/TPY-2 (THAAD) land-based radars, as well as the Navy’s SPY-6 family of radars used on the AEGIS and aircraft carriers.
They’re also producing the APG-79(V)4 AESA radars for the Navy’s F/A-18E/F and EA-18G fleet. The first flight occurred in mid-2022, making it also the first time a GaN-based fighter radar has flown.
Raytheon has already proposed a GaN upgrade to the APG-82 used by the F-15E and F-15EX, which is also the baseline system for the new B-52 AESA radar.
Finally, they are leveraging GaN to take aim at the attritable air vehicle market with a yet-to-be-named half-sized AESA radar.

Northrop Grumman

The company with the world’s largest AESA radar contract—the F-35’s current APG-81 radar—might be a bit behind but they aren’t asleep at the wheel. They are currently delivering GaN-based AESA radars to the Marine Corps for its AN/TPS-80 Ground/Air Task-Oriented Radar (GATOR).

The bottom line

GaN is going to quickly disrupt the way militaries fight and maneuver throughout the frequency spectrum—from stealth to electronic warfare.

As perceived capability advantages instantly vanish it may disrupt entire force structure decisions in the next several years.

Fence in.

Feature Image: An F-35A Lightning II assigned to the 62nd Fighter Squadron prepares to land, Nov. 2, 2020, at Luke Air Force Base, Arizona. The F-35 is capable of reaching speeds of 1,200 mph or Mach 1.6, which is almost two times faster than the speed of sound. Since 1941, Luke has been building the future of airpower by graduating more than 61,000 pilots. (U.S. Air Force photo by Senior Airman Brooke Moeder)

What’s inside the F-35’s new radar?

So what