An Active Electronically Scanned Array (AESA) is a type of radar whose transmitter and receiver functions are composed of numerous small transmission/reception modules that each scan a small fixed area, negating the need for a moving antenna. AESA radars feature short to instantaneous scanning rates and have desirable low-probability of intercept characteristics.

Being immobile, AESA radars have vastly simpler mechanical designs. They require no complex hydraulics for antenna movement nor hinge appendages that are prone to failure and replacement. The AESA radar occupies less space than typical radar, because of its lesser infrastructure requirements and of course its absent range of motion. With these improvements, maintenance crews are far less severely taxed, and the radar is much more reliable.

Mechanical steering may be added to AESA radars for increased radar field of view, however, no such equipped AESA radars currently exist. The movement performance of the antenna would not need to be nearly as great as that of a traditional radar, as the radar sweep is not integral to the contact update rate.

List of AESA radars

• Northrop Grumman/Raytheon AN/APG-77 , for the F/A-22 Raptor.
• Raytheon AN/APG-63(V)2 and AN/APG-63(V)3 , for the F-15C Eagle.
• Raytheon APG-79 , for the F/A-18E/F Super Hornet.
• AMSAR, from the European GTDAR consortium.
• BAE SYSTEMS Seapspray 7000E , for helicopters.