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higurashihougi wrote:
In general PESA does have advantage about the purity, cleanliness and power of the signal. Many AESA models suffer from the distortion of both phase and frequency, like F-22 AESA. Newer AESAs fix the distortion problem, but seems like the power is still not strong enough.
Where did this come from ?
The distinctive advantage of AESA is that, each phase module can be shifted individually, thanks to the fact that each phase module has its own phase shifter. That means, you can put the AESA module in any kinds of unconventional surface instead of the traditional phase plane. Easy to see, you can individually change the phase of each module to create desirable total radar beam, disregard of the position of each module.
AESA Got "A" In it because it has its own amplifier in each module. Even PESA got a phase shifter.. Have a look at this B1B APQ-164 PESA Radar.
Those tubes like object at the array is the Phase shifter.
Many people usually emphasize one advantage of the AESA that is dynamic shifted phase, that it can rapidly move the direction of the radar beam due to the rapid shift of the phase of each modules. But PESA like Irbis and Bars can have dynamic shifted phase, too. PESA dynamic shifted phase is relatively bulky and heavy, and the movement of the radar beam is slower, but well the size of Irbis and Bars is acceptable.
You're keep repeating incorrect description. This is not good and can mislead ppl. All ESA Radar regardless whether it's PESA or AESA are able to shift the beam electronically. and there is no correlation at all between size and beam steering time. It's related to phase shifter design. Ferrite phase shifter is known for its relatively slower steer time (in some tens to hundreds of miliseconds) But now we have digital or diode based phase shifter which is faster and used in airborne radar today.
Ferrite phase shifter however are still in use though application might limited to older ESA's such as APQ-164 and S-300's 30N6 radar.
There are radars who use one common transmitter for all phase module, but each module has its own phase shifter instead of using one common phase shifter for all the modules. Some people call them PESA because of the one common transmitter, but some others call them AESA since each module has its own phase shifter and the phase shift can be controlled individually.
Those who called it AESA are wrong. Phase shifter is NOT an Active device. Active here means it can amplify or modify currents or power that inputted to it.
AESA antenna module have that capability because it has its own amplifier stage. something which PESA don't.
