F-35 Radar Explained: From APG-81 to APG-85

The F-35 radar is the Northrop Grumman AN/APG-81, an active electronically scanned array with 1,676 transmit and receive modules in the nose. It finds and tracks aircraft, maps the ground in high resolution, follows moving vehicles and can be used as a jammer.

A successor, the AN/APG-85, was announced in January 2023 for Block 4 aircraft. It is running late, and from autumn 2026 some new jets are expected to leave the factory with ballast where the radar should be. This guide explains what the F-35 radar does today and what is holding up the new one.

What radar does the F-35 have?

Every F-35 built so far carries the AN/APG-81. Northrop Grumman won the development contract in October 2001 and first flew the radar on a test aircraft in August 2005. It works in the X-band, the frequency range used for fire control.

The antenna is a fixed plate about the size of a large tray, tilted slightly upward so that it does not reflect enemy radar straight back. It has no moving parts. Each of its 1,676 modules is a small transmitter and receiver, and a computer steers the beam by adjusting the timing of each one. The principle is covered in our explainer on how AESA radar works.

What can the F-35 radar do?

Because the beam moves electronically, it can jump between tasks in thousandths of a second. The radar can search a sector of sky, track several aircraft, guide AMRAAM missiles and build a ground map, apparently all at once. The pilot does not run these modes one by one; the mission computer assigns the radar’s time according to what the tactical picture needs.

In air-to-ground work it produces synthetic aperture images sharp enough to pick out vehicles and buildings through cloud, and it can follow moving targets on roads. That lets the jet find and attack targets in weather that blinds infrared sensors.

The array can also concentrate its power into a narrow beam at an enemy radar, which turns it into a jammer. And it can spread its energy across frequencies in patterns that are hard for warning receivers to notice, a technique called low probability of intercept. Both matter for F-35 stealth: a stealth aircraft that announces itself with its own radar has wasted the effort.

What is the AN/APG-85?

The APG-85 is the radar for Block 4. Northrop Grumman announced it in January 2023 and has released almost no details beyond saying it will fit all three variants and counter current and future threats. Trade press reports say it uses gallium nitride modules, which handle more power than the gallium arsenide parts in the APG-81 and give more range and jamming power for the same antenna size.

More power brings two problems. The new radar needs a different forward bulkhead from the APG-81, so the two are not interchangeable on the production line. And it draws more electrical power and cooling than the current engine and thermal system were sized for, which ties it to the planned engine core upgrade and a new power and cooling system.

Why is the APG-85 delayed?

Development has not kept pace with production. Aircraft built with the new bulkhead cannot take the old radar, and the new radar is not ready in numbers. The Aviationist, citing the Pentagon’s testing office, reported in March 2026 that jets would be delivered with ballast in place of the radar from autumn 2026 and would not be assigned to combat units soon.

This sits on top of the TR-3 delay. The same report said no combat-capable TR-3 aircraft had been delivered by September 2025. A jet without a radar can still be flown for training, and the radar can be fitted later, but each retrofit costs money and time that the programme had not planned for.

How does the F-35 radar compare with others?

Module count is a rough guide to power and range, though software and processing matter as much. The F-22’s radar has a larger antenna. The Rafale’s is smaller because the nose is smaller.

What sets the F-35 apart is less the radar itself than what is done with its data. Radar tracks are merged with infrared and electronic detections before the pilot sees them. The aircraft is introduced in what the F-35 is, and the missiles the radar guides are in our guide to F-35 missiles.

Frequently asked questions

What radar is in the F-35?

The Northrop Grumman AN/APG-81, an X-band active electronically scanned array.

What is the range of the F-35 radar?

The published figure is more than 150 km. The real figure is classified and depends on the size of the target.

Can the F-35 radar jam enemy radars?

Yes. The array can focus its power on a hostile radar as a form of electronic attack.

What is the difference between the APG-81 and APG-85?

The APG-85 is the newer radar for Block 4 aircraft. It is reported to use gallium nitride modules for more power, and it needs more cooling and a different bulkhead.

Why are some F-35s being delivered without radar?

The APG-85 is late and aircraft built for it cannot take the older APG-81, so ballast is fitted until radars are available.

Is the F-16’s new radar related to the F-35’s?

Yes. The APG-83 fitted to upgraded F-16s draws on technology from the APG-81.