AESA

An Active Electronically Scanned Array (AESA) radar represents the current state of the art in airborne and shipborne radar technology. Unlike older mechanically scanned radars that physically rotate an antenna to sweep a beam across the sky, an AESA uses hundreds or thousands of small transmit/receive (T/R) modules, each capable of generating and receiving its own radar signal. The beam is steered electronically by adjusting the phase and timing of signals across the array.

This architecture gives AESA radars enormous advantages. They can track hundreds of targets simultaneously, switch between air-to-air and air-to-ground modes almost instantly, operate at multiple frequencies to defeat jamming, and even function as electronic warfare systems themselves. The AN/APG-81 on the F-35 and the AN/APG-82 on the F-15EX are among the most capable AESA radars in service.

AESA technology has become a defining feature of modern combat aircraft. Fourth-generation fighters are being retrofitted with AESA radars to extend their relevance, and the technology is increasingly appearing on naval vessels, ground-based air defense systems, and even unmanned aircraft.