AESA elements counting by Japanese(so terrible)

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taog

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Unread post11 Apr 2014, 16:14

hornetfinn wrote:I've done some calculations about the potential capabilities of APG-81 in relation to raw detection range. If we assume that the pictures of APG-81 T/R module count are correct (well over 1600 modules) and if we assume it uses the best publicly known and marketed GaAs T/R modules (about 16W), we get some impressive numbers. We have to remember that it could well use even more powerful modules as they are available. 25W modules are sold already and even more powerful ones are in development. Even with 10W modules (that became available more than 15 years ago), it'd be very powerful radar set.

With 1676 modules and 10 W power each, giving almost 17 kW peak power with 700 mm antenna diameter (assumed to be perfectly circular), I've calculated that the conservative maximum detection range estimate would be about 360 km or almost 200 nmi against 3 m^2 target. With 16W modules this increase to slightly over 400 km. If the antenna area is larger, then it would give somewhat better range. 800 mm diameter would give about 450 km range with 16W modules. If we calculate the upper boundary of detection with 1676 16W modules and 800 mm diameter antenna with current tech LNA (low noise amplifier) used in receiving path, we get maximum detection range of about 550 km. So we get detection range of 360-550 km for 3 m^2 RCS target depending on antenna diameter and T/R module power and losses. Against 0.1 m^2 target detection range would be between 160 and 240 km. Against 0.001 target it would be between 50 and 75 km.

All these are of course using only single very high power radar beam to search for long range targets within a limited search area or areas without any restrictions. Using multiple beams or using very wide search area or using LPI waveforms is likely to shorten the detection range. But it could still theoretically search for the whole radar field of regard to 250-400 km range depending on exact performance figures and scan time.

All in all this shows very much that the APG-81 is likely going to be extremely powerful and versatile radar set. In air to air combat, it's very likely it's going to see other fighters well before they can see it. It can detect latest 4th generation fighters with reduced signatures (like EF Typhoon, Dassault Rafale or SH) at significant ranges (about 200 km away) even when they are almost clean. Those 4+ generation fighters would be able to detect F-35 at significantly shorter ranges, 50 km or less even with very good AESA radars. That alone gives F-35 (and F-22) a huge advantage in aerial combat.


1.i ask someone who study radar,he say APG-81/80 use different radiator than others like 77/79,the "unit" is the red circle in the below picture. But he say even counting in this way, APG81's elements amount still >1600(i count again,APG81 change to 1628 elements,80 change to 974 elements)
Image
2.F35 's antenna size be considered as >=F18,which with 720~730mm diameter
3.yeah,Irbis-E 's 90km long detection with RCS=0.01 target is based on reduce the search volume → rise the dwell time to enhance its range
4.update the newest report about AFAR-X:it has 1526 elements,will be tested onT-50-5 ,achieve the expected ability with air-air and air-ground mode ,but"like other new system,there still some problems wait to be solved"

http://vpk.name/news/108050_umnaya_obsh ... ak_fa.html
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taog

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Unread post05 May 2014, 08:26

different pattern of radiator. APG81 use the right sample

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spazsinbad

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Unread post05 May 2014, 08:53

The image above does not show (perhaps not able to be hotlinked? dunno) so here it is (edited): http://i2.hoopchina.com.cn/blogfile/201 ... 94*162.jpg
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AESAelement.gif
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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disconnectedradical

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Unread post05 Jul 2014, 21:41

One more image of the -81 from Key Pub's F-35 special (which I would recommend).

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