Active Electronically Scanned Array

An Electronically Scanned Array (AESA), also known as active phased array radar is a type of radar whose transmitter and receiver functions are composed of numerous small transmit/receive (T/R) modules. AESA radars feature short to instantaneous (millisecond) scanning rates and have a desirable low probability of intercept.

As solid state devices, AESA radars have vastly simpler mechanical designs. They require no complex hydraulics for antenna movement nor hinge appendages. The AESA radar occupies less space than typical radar, because of its reduced infrastructure requirements and of course its absent range of motion. With these improvements the radar is much more reliable, and requires much less maintenance.

Main advantages over mechanically scanned arrays are extremely fast scanning rate, much higher range, tremendous number of targets being tracked and engaged (multiple agile beams), low probability of intercept, ability to function as a radio/jammer, simultaneous air and ground modes, Synthetic Aperture Radar.

AESA radars for increased radar field of view; 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.

Features

AESA radars have:
*High ECM resistance:
**The extremely fast scan of the radar makes it difficult for an ECM device to find the correct azimuth and elevation in which the radar's main lobe is currently directed.
**High gain associated with AESA radars gives them high ERP, which makes it difficult for an active ECM device, using noise jamming techniques, to successfully jam such a radar.
*The extremely fast scan of the emitter gives it LPI features.
*Less susceptibility to voltage failures, due to the relatively very low voltage in which each and every single radiating element operates; This is combined with graceful degradation.

The Difference Between AESA and PESA

In a passive electronically scanned array (PESA), the microwave feed network in the back of the antenna is powered by a single radio frequency (RF) source (magnetron, klystron, TWT, etc.), sending its waves into phase shift modules (usually digitally-controlled), which, in turn, feed the numerous emitting elements.

An AESA, instead, has an individual RF source for each of its many transmit/receive elements, making them "active".

This provides a level of redundancy for the system, as the failure of individual or groups of T/R modules would not necessarily keep the radar from functioning.

AESA radars replace the traditional radar RF sources (magnetron/klystron/TWT), which usually require extremely high operating voltage and power, with multiple solid state RF sources operating at low voltage (40 to 60 volts). Solid state electronics use silicon or gallium arsenide based power amplifier technology and benefit to some extent from mass production techniques developed for consumer electronics. US based manufacturers of the AESA radars used in the F22 and Super Hornet include Northrop Grumman [ [http://www.irconnect.com/noc/press/pages/news_releases.html?d=116105 Northrop Grumman Successfully Completes F-22 Radar Flight-Test Certification ] ] and Raytheon. [ [http://www.raytheon.com/products/aesa/ Raytheon Company: Products & Services: AESA Technology ] ] These companies also design, develop and manufacture the transmit/receive modules which comprise the 'building blocks' of an AESA radar. The requisite electronics technology was developed in-house via Department of Defense research programs such as MIMIC Program. [ [http://www.csmantech.org/Digests/2003/2003PDF/1-2.pdf A DARPA Perspective on the Future of Electronics ] ] [http://www.ll.mit.edu/news/journal/pdf/vol12_no2/12_2devphasedarray.pdf]

List of AESA radars

Airborne systems

* Northrop Grumman/Raytheon AN/APG-77, for the F-22 Raptor
* Northrop Grumman AN/APG-80, for the F-16E/F Block 60 Fighting Falcon
* Northrop Grumman AN/APG-81, for the F-35 Joint Strike Fighter
* Northrop Grumman Multi-role AESA, for the Boeing Wedgetail (AEW&C)
* Northrop Grumman APY-9, for the E-2D Advanced Hawkeye
* 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 and EA-18G Growler
* Raytheon AN/APQ-181 (AESA upgrade currently in development), for the B-2 Spirit bomber
* AMSAR, research from the European GTDAR consortium, for Eurofighter and Rafale fighter Radar
* Captor-E CAESAR (CAPTOR Active Electronically Scanning Array Radar)
* RBE2-AA Radar à Balayage Electronique 2 - Active Array
* SELEX Seaspray 7000E, for helicopters
* SELEX Vixen 500E
* Mitsubishi Electric Corporation J/APG-1, AESA for the Mitsubishi F-2 fighter
* Ericsson Erieye AEW&C and NORA AESA for JAS 39 Gripen
* Phazotron NIIR Zhuk-AE, for MiG-35
* Tikhomirov NIIP Epaulet-A
* Elta EL/M-2083 aerostat-mounted air search radar
* Elta EL/M-2052, for fighters
* Elta EL/M-2075 radar for the IAI Phalcon AEW&C system
* DRDO AESA radar for the DRDO AEW&CS

Ground and sea-based systems

* APAR Thales multi-function radar, primary sensor of Dutch De Zeven Provinciën and German Sachsen class frigates
* Selex EMPAR (European Multifunction Phased Array Radar)
* Elta EL/M-2080 "Green Pine" ground-based early warning AESA radar
* Elta EL/M-2248 "MF-STAR" multifunction naval radar
* AN/SPY-3 multi-function radar for U.S. DD(X), CG(X) and CVN-21 next-generation surface vessels
* Raytheon U.S. National Missile Defense X-Band Radar (XBR)
* MEADS's fire control radar
* THAAD system fire control radar
* BAE Systems Insyte SAMPSON multi-function radar for UK Type 45 destroyers
* FCS-3 Mitsubishi Electric Corporation (Melco)
* OPS-24 Mitsubishi Electric Corporation (The world's first Naval Active Electronically Scanned Array radar)
* J/FPS-5 Japanese ground-based next generation Missile Defense Radar
* CEAFAR CEA Technologies Naval Phased Array

ee also

* Radar
* Phased array
* Transmitter
* Receiver
* Passive electronically scanned array

References

External links

* [http://www.ausairpower.net/aesa-intro.html Active Electronically Steered Arrays – A Maturing Technology]
* [http://www.flug-revue.rotor.com/FRHeft/FRH9812/FR9812c.htm FLUG REVUE December 1998: Modern fighter radar technology]
* [http://www.mwjournal.com/article.asp?HH_ID=AR_29 Phased Arrays and Radars – Past, Present and Future]