AESA, PESA... What does it mean?

[Scorpion86]

I've read a lot of discussions in this forum and I found myself confused when the discussion centered around radars. AESA, PESA and many other terms didn't mean anything to me. I realise my knowledge of radar technology is woefully inadequate.
Is there any souce you can point to that spells out the various types of radar technology, it's development, capabilities, etc.? (Preferably online and free?)

Best regards,
Scorpion86

[thewood1]

https://radausa.com/blog/pesa-radar-vs-aesa-radar

[Filitch]

Another very informative site
https://www.radartutorial.eu/06.antenna ... na.en.html

[SeaQueen]

AESA is "active electronically scanned array."
PESA is "passive electronically scanned array."

The PESA is not a passive sensor, though. In the old days, the radar energy had to be created by big things called klystrons or magnetrons which are basically just big electronic gizmos for making radio waves and amplifying them. Those old radars had a dish that physically moved and were termed "mechanically scanned."

With the advent of fast solid state electronics, however, it became possible to introduce a phase delay into the RF signal. That turns out to be important because by changing the phase delay between different emitting portions of the antenna, you can shape and point the radar beam. That means you don't need to mechanically point the radar back and forth to scan with it. Such a radar is called "electronically scanned." A radar with an old style klystron or magnetron and electronics to add a phase delay to the signal coming out of different elements of the antenna is termed a PESA. PESA radars are common on Russian and some Chinese aircraft as well as surface systems. A SLOT BACK is an example of a PESA radar.

The West never really messed with the PESA idea much. Instead, they waited for technology to advance even more and the source of the radar energy could be built into the radar antenna itself. An AESA radar antenna forgoes klystrons and magnetrons and instead has an antenna composed of lots of little "transmit/receive modules." There's no wave guides to carry the radar energy to the antenna. It's all created right there on the surface of the antennas. Aside from no longer needing to be mechanically moved to scan an area, AESA radars opened up a whole new world of options for radars. Those include lots of different (and more complicated) modes, multibeam capabilities, the possibility of being in multiple modes simultaneously, resistance to jamming, and other things. It also allowed for MASSIVELY improved antenna gains and the improved detection ranges that go with it. An AN/APG-63(V)2 is an example of an AESA.

How is that?

[Swant]

Very nice explanation

[Scorpion86]

(...)

How is that?

Quick, punchy, and to the point. That how I like it!

I guess the beam shaping capabilities of the AESA is what gives them all those fancy abilities I heard about recently. Correct me if I'm wrong, but aren't AESA radars capable of being used in a passive mode as a sort of RWR or in an active mode as a jammer?

[tankslapper]

The West never really messed with the PESA idea much. Instead, they waited for technology to advance even more and the source of the radar energy could be built into the radar antenna itself.

There’s quite a few examples of Western PESA radars. AEGIS ships, the E-3, B-1, B-2, JSTARS, Patriot, and various ballistic missile warning systems have all had passively scanned radars. AESA has only really been practical since high power solid state transmit elements were developed around the 90s.