Chinese Radar Developments - KLJ series and others

very interesting here as part of the article to talk about diamond usage as heatsink for various applications and Huawei's interest and patents in it.

5G base station power amplifier is a pretty good proxy of the upper limit of what current material can withstand.

It says here that power amplifier density of single MMIC can reach 300 W/cm2.

if we put that inside the nose of a fighter jet.

Something with a 100 cm diameter nose (1m nose is basically flanker), that is 50*50*3.14 = 7850 cm2.

Even with that, the theoretical limit of the radar for power could be 2.355MW. Of course in reality, you might not want each MMIC to be side to side with each other, so it's going to be less than that.

But if we use something ike J-36 nose of 200cm diameter, you'd 4x that. So, that would be 8MW. Not that I think a fighter jet would actually be able to do that anytime soon, but with diamond substrate, the sky is the limit when it comes to radar power. At minimum, the constraint is not on the MMIC itself but rather whatever is providing the power & whatever is doing the cooling.

Back in the early radar days the fighter radars were into the hundreds kilowatts range, one of the most famous being the Smerch at 600kw, reportedly able to fry animals. Might we see the return of the triple digit kw radars soon? Modern trend of AESA uses for EA and DEW seems to indicate that.

mack8 said:

Back in the early radar days the fighter radars were into the hundreds kilowatts range, one of the most famous being the Smerch at 600kw, reportedly able to fry animals.

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Feels unlikely as today's fighter radars are mostly using High-Medium PRF, lots of pulses and lots of average power basically high duty cycle. High peak power of Smerch was the result of technology available at that time which can only allow Low PRF waveform and basically there was no means yet to solve ambiguity coming from using High PRF waveform. Thus Smerch use Low PRF, with short pulse and very high peak power level, but low duty cycle to provide adequate performance. The average power of Smerch afaik was only about 57 Watt.

Later radars like say Zaslon have High-medium and Low PRF as the processing are more advanced, Zaslon have 200 KHz PRF and thus higher average power of 2.5 KW. The peak power is somewhere along 10-12.5 KW. Irbis can reach 20 KW peak with average power Twice of that of Zaslon. Those were adequate for radar task.

Arguably tho, things like EA does not need much more or even less as with EA like jamming you will be using advanced waveform which mimic the enemy radar's emmission. This doesnt need much power except maybe tens of Watts. High power is only required for Noise jamming and this is rather inconvenient for fighter aircraft radar as steerable antenna is desireable as Noise jamming are typically done outside enemy weapon range and in race-track pattern similar as AEW.

DEW require so much more particularly to compensate for frequency mismatch say you want to attack missiles and to couple enough power to target, but might be with limited payoff for fighter aircraft radar, better to use laser or even missiles.

Stealth target better be handled by say other sensor which then can allow the radar to focus on specific area, range then can be achieved by trading off coverage and dwell time (smaller coverage = more dwell time can be allocated to an area = longer detection range)