Active Electronically Scanned Array

The Active Electronically Scanned Array ( AESA ), also known as active phased array radar is a radar system with active electronic beam scanning. Its function is based on many individual small R modules.

The alignment and focusing of the radar beam is the same as for passive phased array radar systems ( PESA ) systems by the phase shift between the individual modules on the antenna surface. An AESA radar thus has the same features and benefits as a passive phased-array radar. The difference is that here each module has its own RF generator, while the passive variant of a common RF source used, the signal is modified using digitally controlled phase -shift modules. The supply lines of the traveling wave tube to the phase shifters omitted in AESA systems, whereby they are more compact to construct. The circuit complexity is, however, a total greater for AESA.

Use in aircraft

Compared to classical radar systems is basically a mechanically simpler a phased array system. It does not require actuator motors for pivoting the radar beam by side or elevation angle, or hinges, or other parts, which may be susceptible to failure. Therefore, it requires less space, which is advantageous in airborne systems. Furthermore, the maintenance of the radar is easier while increasing the reliability of: up to 10% of the AESA modules fail, without compromising the function of essential. In contrast, if the traveling-wave tube with a mechanically controlled or PESA radar, so the radar falls out completely.

When used in combat aircraft are the advantages over a conventional radar:

  • High speed of a " radar beam passage ", but is limited by the signal propagation time.
  • Long range in a straight line of sight, falling with increasing tilt angle, because the effective antenna area decreases.
  • Several goals can be pursued simultaneously.
  • Overall, smaller transmission power, thus less likely to be discovered.
  • Use as a jammer ( jamming ) is possible.
  • Increased reliability, several modules may fail without the functionality suffers.

Advantages over the passive variant PESA:

  • Increased reliability and component life, because, among other things, no high voltages and traveling wave tubes are needed.
  • Lighter weight with comparable performance
  • Lower heat generation compared to constructed with PIN diodes Radant lenses.
  • Increased versatility (eg parallel use as an active jamming system, IFF system and communication system )
  • The transmission power must not pass through the phase shifter, as received signals, which increases the range. Phase shift is achieved by appropriate phase-shifted drive of the individual transmission elements. In a PESA antenna sensitivity can be reduced by 10 to 15 dB in this area.
  • No switching sidelobes as controlled by PIN diodes Radant lenses.
  • Faster scanning speed compared to ferromagnetic lenses.
  • Higher antenna gain with simultaneous high sidelobe attenuation.
  • Better ECCM properties
  • Significantly lower sidelobe
  • Simultaneous transmission on different frequencies, thereby Electronic countermeasures more difficult and better LPI properties are enabled. Current airborne radars, however, are limited by their design to a small number of transmit and receive channels at different frequencies. Also, the range is greatly reduced by this method.


  • Increased control effort compared with ferromagnetic lenses that require only row and column addressing.
  • Higher production costs, more complex wiring of the antenna.
  • Must be installed at an angle, otherwise increases the frontal radar cross section.
  • Limited field of view of up to ± 60 ° in the vertical and in the horizontal direction.

To the field of view of max. ± 60 degrees to increase and improve the poor focusing in the edge region, it makes sense, even a AESA radar move to build. The mechanics can be easier than for classical systems it but because it must pursue one goal only roughly. For fixed installations where weight and volume play a minor role, as on aircraft carriers and frigates, one assigns turn every direction a rigid flat antenna; hence weather influences are avoided rotating radar dishes.

List of AESA radars

Airborne Systems

  • AN/APG-63 ( V) 2 in the F- 15C Eagle (2000 was the first operational AESA radar in the world was introduced )
  • AN/APG-63 (V ) 3 for the F-15C and F- 15SG; 2006 at the prototype stage
  • AN/APG-77 in the F- 22 Raptor
  • AN/APG-79 in the F/A-18E/F Super Hornet
  • AN/APG-80 in the F- 16E / F Block 60 Fighting Falcon
  • AN/APG-81 in the F- 35 Lightning II
  • AN/APG-82 ( originally called the AN/APG-63 (V ) 4 ) as a upgrade for F -15E Strike Eagle and the F- 15SE Silent Eagle
  • AN/APQ-181 ( AESA upgrade currently in development), the B -2 stealth bomber
  • BAE Systems Seaspray 7000E, in helicopters
  • Captor - E for the Euro Fighter Typhoon
  • Ericsson Erieye AEW & C and NORA AESA in the Saab 39 Gripen
  • IAI Phalcon AEW & C Elta radar system
  • Mitsubishi Electric J/APG-1 AESA in the Mitsubishi F-2 fighter aircraft
  • Northrop Grumman SABR, for F- 16 Fighting Falcon upgrades
  • ( Extradite from 2012 in the standard F3) RBE2 -AA Rafale for the Dassault fighter aircraft from the fourth tranche of purchases.

Ground - and sea-based systems

  • APAR (Active Phased Array Radar ) ship -based multi -function radar
  • IAI EL/M-2080 " Green Pine ", ground-based early-warning AESA radar
  • Sea -Based X-band radar tracking of intercontinental ballistic missiles
  • AN/TPY-2 for the THAAD system
  • AN/SPY-3 for the Zumwalt - class, Gerald R. Ford - class and CG (X) ( Warships of the next generation )
  • SAMPSON for Elizabeth Class Daring class and Queen