what I mean is if I obtain only one of those T/R module and try it at home, turn it on at X band 3cm wavelength, it would reach 200KM far? which is the spec jet fighter AESA radar spec.
Phase Array Radar, theory and operation
- Thread starter lilzz
- Start date
what I mean is if I obtain only one of those T/R module and try it at home, turn it on at X band 3cm wavelength, it would reach 200KM far? which is the spec jet fighter AESA radar spec.
No it won't.
The range is also due to the beam forming techniques that see hundreds if not thousands of emitters as a whole, and you can't do beam forming with only one emitter. This is not to mention that the range obtained is the total output of all these emitters.
The range is also due to the beam forming techniques that see hundreds if not thousands of emitters as a whole, and you can't do beam forming with only one emitter. This is not to mention that the range obtained is the total output of all these emitters.
Just a thought, on the ship, there consists of 4 phase array radar planes which covers 360 degree, but on jet fighter no such luxury, there's only one plane.
So, on jet fighter the phase array radar can only form 180 degree of coverage? The jet fighter's radar can't form a beam to goes backward therefore can't see anything coming in the rear??
basing on the theory of phase array radar principle.
any thoughts on that.
So, on jet fighter the phase array radar can only form 180 degree of coverage? The jet fighter's radar can't form a beam to goes backward therefore can't see anything coming in the rear??
basing on the theory of phase array radar principle.
any thoughts on that.
Actually the phase array radar on the plane can probably cover up to 120 degrees effectively, and performance falls off as the beam shifts the further away from the bore-center. You are looking at what the disadvantage of electronic scanning that advocates and marketers refuse to tell you, that as you shift the beam further off center to the sides, more interference is used by the shifters to shift the beam down. This means greater signal loss or efficiency, and at the same time, more heat is being generated, and heat is the outcome of wasted energy. That's the reason why ESAs don't have the flexibility and FOV of mechanical scanning radars which can be capable of turning a full 90 degrees in some antennas.
To counter this, ESAs are generally put into a mechanism that allows for some limited mechanical movement.
And of course, you can't see what is backward. You have to put a rear facing radar but most planes rely on passive receivers called RWRs installed on the back that will detect and warn incoming radar.
To counter this, ESAs are generally put into a mechanism that allows for some limited mechanical movement.
And of course, you can't see what is backward. You have to put a rear facing radar but most planes rely on passive receivers called RWRs installed on the back that will detect and warn incoming radar.
On the ship phase array radar, Type 348 radar.
However, the Chinese phased array radar differs considerably from the American AN/SPY-1 in that instead of having separate dedicated transmitting and receiving elements, each element of the antenna array of the Chinese radar is capable of both transmitting and receiving, a function similar to the SAMPSON active phased array radar, and just like the SAMPSON system, each transmitting/receiving module of Type 346 radar has separate transmitter and receiver, thus enabling it to continuously receive signals. The radar has designation of H/LJG-346. Its operational frequency band is not yet known to have been published. According to Chinese sources, the biggest difficulty Chinese faced in the early 2000's was to reduce the unit cost of the indigenously produced MMIC used for the radar, because the Chinese MMIC cost is 25 times of its American counterparts, around $ 12,500 in comparison to the $ 500 of American MMIC.
============================================================
Wonder if as of now whether the cost of MMIC in CHina still as high as quoted in wiki. Do they use different processes in China which cause the big difference in price?
One the main fab supplying miliatary RF devices in US is Triquint semiconductor. There aren't any dedicated fabs in china for that.. wondering if those fabs making wireless for cellphone can be used for that purpose.
anyway, price has to come down in order to be practical and wide use.
However, the Chinese phased array radar differs considerably from the American AN/SPY-1 in that instead of having separate dedicated transmitting and receiving elements, each element of the antenna array of the Chinese radar is capable of both transmitting and receiving, a function similar to the SAMPSON active phased array radar, and just like the SAMPSON system, each transmitting/receiving module of Type 346 radar has separate transmitter and receiver, thus enabling it to continuously receive signals. The radar has designation of H/LJG-346. Its operational frequency band is not yet known to have been published. According to Chinese sources, the biggest difficulty Chinese faced in the early 2000's was to reduce the unit cost of the indigenously produced MMIC used for the radar, because the Chinese MMIC cost is 25 times of its American counterparts, around $ 12,500 in comparison to the $ 500 of American MMIC.
============================================================
Wonder if as of now whether the cost of MMIC in CHina still as high as quoted in wiki. Do they use different processes in China which cause the big difference in price?
One the main fab supplying miliatary RF devices in US is Triquint semiconductor. There aren't any dedicated fabs in china for that.. wondering if those fabs making wireless for cellphone can be used for that purpose.
anyway, price has to come down in order to be practical and wide use.
The costs should be lower by now as a matter of fact due to an unfortunate side effect in the China semiconductor industry. There is starting to be too many too many fabs and ventures in China, and even the GaAs is going into overproduction.
Even with the prices down, nonetheless its futile to pursue this course because GaAs MMIC is becoming obsolete thanks to GaN MMIC. Again, there is now a gold rush into this material around the world even in China becomes it promises a whole new era of telecommunications where you get less stations but each covering much wider ranges with much more power. Currently no use in pursuing GaAs AESA designs when second generation GaN AESA designs promise to be much more powerful. To put it this way, a GaAs MMIC generates up to 4 watts, so a thousand element array will generate 4000 watts. But a GaN element can generate up to 50 watts (Japanese research), so let's say conservatively, you got 20 watts per element, an array with a thousand elements can generate up to 20,000 watts. When you get 20 kilowatts of radar into a tight beam, that's so brute force you can't even stealth it. At 50 watts per element, the entire array can become a death ray machine.
I shudder at the thought of MMICs this powerful in your celphone being held up close to your brain.
Even with the prices down, nonetheless its futile to pursue this course because GaAs MMIC is becoming obsolete thanks to GaN MMIC. Again, there is now a gold rush into this material around the world even in China becomes it promises a whole new era of telecommunications where you get less stations but each covering much wider ranges with much more power. Currently no use in pursuing GaAs AESA designs when second generation GaN AESA designs promise to be much more powerful. To put it this way, a GaAs MMIC generates up to 4 watts, so a thousand element array will generate 4000 watts. But a GaN element can generate up to 50 watts (Japanese research), so let's say conservatively, you got 20 watts per element, an array with a thousand elements can generate up to 20,000 watts. When you get 20 kilowatts of radar into a tight beam, that's so brute force you can't even stealth it. At 50 watts per element, the entire array can become a death ray machine.
I shudder at the thought of MMICs this powerful in your celphone being held up close to your brain.
I think China should not only build fabs base on JV. It needs to able build the equipments for thefab. Currently, most of the equipments for fabs came from US companies like Applied Material, Lamb Research.
Wonder if US place export restriction on those equipments to China, probaby does. therefore China can only get those older generation tech equipments espcially specilaty semiconductor, MMIC, the commerical CMOS are probably more relaxed.
But CHina can build theirs then they can keep uptodate /w western standard. CHina and /w closer tie to Taiwan can draw upon its experience to form JV to build those equipments. At this pt even Taiwan have to purchase equipments from US.
Be able to building hightech equipments are really leading edge and demonstrate its master of the technology
Wonder if US place export restriction on those equipments to China, probaby does. therefore China can only get those older generation tech equipments espcially specilaty semiconductor, MMIC, the commerical CMOS are probably more relaxed.
But CHina can build theirs then they can keep uptodate /w western standard. CHina and /w closer tie to Taiwan can draw upon its experience to form JV to build those equipments. At this pt even Taiwan have to purchase equipments from US.
Be able to building hightech equipments are really leading edge and demonstrate its master of the technology
Small Chinese upstart companies are already starting to build their own equipment but these are mainly for 4", 6 and 8" wafers and only recently plan to begin in 12" (300mm) wafers. One upstart I believe is actually made of former Applied Material executives But the experience in Taiwan and S. Korea shows upstarts having difficulty competing with established giants. Taiwan, Japan, S. Korea and Europe tend to supply the most advanced tools.
according to past issue of Miltech,claim that maximum power output (or cap) for GaAs MMIC is 10 watts.
GaAs MMIC being developed for Captor AESA is 10 watts.4 years ago, Nanjing radar also fabricate GaAS MMIC but the powerout is only 4 watts.