Active Electronically Scanned Array
Understanding AESA
AESA represents the current state of the art in radar technology. By placing a complete transmit/receive chain at each element, AESA achieves capabilities impossible with passive or mechanically scanned arrays.
AESA Advantages
- Multi-function: Simultaneously search, track, and engage multiple targets using independent beams.
- Graceful degradation: If 10% of T/R modules fail, gain drops ~0.5 dB. Array keeps operating.
- Low probability of intercept: Can spread energy across frequencies and directions, making detection difficult.
- Electronic warfare: Can function as a jammer while simultaneously performing radar functions.
AESA Examples
- AN/APG-77 (F-22): ~2000 elements, X-band. The premier fighter AESA radar.
- AN/APG-81 (F-35): ~1200 elements. Multi-function AESA.
- SPY-6 (DDG-51): S-band shipboard AESA. ~5000 elements per face.
Frequently Asked Questions
What is AESA?
AESA is a phased array with a T/R module at each element. It enables multi-beam operation, rapid beam switching, graceful degradation, and simultaneous radar/EW functions. The standard for modern military radar.
What is the difference between AESA and PESA?
PESA (Passive ESA) uses a central transmitter with passive phase shifters at each element. AESA has active T/R modules at each element. AESA provides higher reliability, multi-beam capability, wider bandwidth, and better ECCM.
How many elements does an AESA need?
Depends on the application. Fighter radar: 1000-2000 elements. Shipboard: 3000-10000. Ground-based: 10000+. 5G base station: 64-256 (Massive MIMO, a commercial form of AESA). More elements = more gain, narrower beam, more flexibility.