Active electronically scanned array (AESA) radar
An active electronically scanned array (AESA), is a type of phased array antenna, that is a computer-controlled array antenna in which the beam of radio waves can be electronically steered to point in different directions without moving the antenna. In the AESA, each antenna element is connected to a small solid-state transmit/receive module (TRM) under the control of a computer, which performs the functions of a transmitter and/or receiver for the antenna. This contrasts with a passive electronically scanned array (PESA), in which all the antenna elements are connected to a single transmitter and/or receiver through phase shifters under the control of the computer. AESA's main use is in radar, and these are known as active phased array radar (APAR).
The AESA is a more advanced, sophisticated, second-generation of the original PESA phased array technology. PESAs can only emit a single beam of radio waves at a single frequency at a time. The AESA can radiate multiple beams of radio waves at multiple frequencies simultaneously. AESA radars can spread their signal emissions across a wider range of frequencies, which makes them more difficult to detect over background noise, allowing ships and aircraft to radiate powerful radar signals while still remaining stealthy. Most of the radar systems used in modern combat aircraft are AESA systems.
APG-79 AESA radar for F-18 fighter:
Northrop Grumman APG-83 scalable agile beam radar (SABR) for F-16:
leonardo Raven ES-05 radar for the Gripen NG
Front and side mounted AESA on Su-57
KLJ-7A AESA for JF-17 thunder Block 3
J-20 Stealth AESA
Osprey radar on the AW101 helicopter by leonardo
Dassault Rafale Thales RBE2 AESA radar
Eurofighter typhoon AESA radar