Naval missile guidance thread - SAM systems

[Anlsvrthng]

I am curious. Can you quantify these losses? Waveguides are known to have lower losses than coaxial cables, and I've seen coaxial cables that have losses as low as 0.03db/m in the lower part of the S-band region and rated for peak powers of 300-425kW.

Please, Log in or Register to view URLs content!

0.1db/meter

 

[Anlsvrthng]

Here is another way to look at it.

View attachment 58005

Maybe you haven't realised, but it show the phase sifters between the master oscillator and the active elements.

That makes sense, the phase shifter needs either same exotic material or a switch , both with losses.

 

[nlalyst]

View attachment 58003
Would be neat to see those diagrams.

After the phase shifters, you only have the antenna. I don't see how you can put an amp or anything but the antenna beyond the phase shifters.

Isn't this actually an example of an AESA architecture where the phase shifter comes before the last stage amps, therefore refuting what you're just saying? Also, the system is going analog from within the waveform generator, so the same argument about "analog losses" that PESA suffer would apply to this AESA design as well.

 

[nlalyst]

There are three alternative methods where to put the time delay.

Please, Log in or Register to view URLs content!

In all the 3 alternatives the phase shifter comes before the final amplification step. I don't get your argument as with every example you posted you contradict yourself and confirm what @Anlsvrthng is saying?

 

[nlalyst]

Would be neat to see those diagrams.

Here's another one, again demonstrating an AESA architecture that goes analog after the WFG:

Source:

Please, Log in or Register to view URLs content!

 

[Tam]

Isn't this actually an example of an AESA architecture where the phase shifter comes before the last stage amps, therefore refuting what you're just saying? Also, the system is going analog from within the waveform generator, so the same argument about "analog losses" that PESA suffer would apply to this AESA design as well.

Waveform generator is after the digital beamformer and is about where the A/D converter is. AESA goes analog right on the module itself. PESA goes analog before the main transmitter, through the analog beamformer, and throughout to the antenna.

Already showed that diagram to you.

 

[Tam]

So, the difference is the line losses. B

Example ?



How ?

This thickness ,mass and cooling requirement is way higher than for PESA.

See.

 

[Tam]

x

 

[nlalyst]

Waveform generator is after the digital beamformer and is about where the A/D converter is. AESA goes analog right on the module itself. PESA goes analog before the main transmitter, through the analog beamformer, and throughout to the antenna.

Already showed that diagram to you.

Maybe you want to check your eyes? The beamformer clearly comes after the exciter on that slide. Also, no mention of it being digital.

Plus, I showed you an AESA architecture where the beamformer works on analog inputs. In case you missed it:


This clearly contradicts your statement: "AESA goes analog right on the module itself. "

This is what you said, in a previous post:

Power loss and signal distortion takes place after the signal is converted from digital to analog. With AESA, the ADC is on the module itself, it is only analog by a few inches to the antenna, but on the PESA, the long line path from the transmitter to the Tx element is analog.

I just gave you an example of an AESA architecture without a DAC on the T/R module and what looks like a pretty long analog path through a sequence of analog filters, amplifiers and an analog beamforming network before it reaches the TRMs. Clearly, having the DAC on the module itself is not a defining feature of an AESA architecture.

It seems you were wrong about this, just like you were wrong about the phase shifter placement:

After the phase shifters, you only have the antenna. I don't see how you can put an amp or anything but the antenna beyond the phase shifters.

Except all the examples both you yourself and I provided show otherwise.

 

[Tam]

Example ?

SPY-1 family for example, has multiple receiving subarrays.

Please, Log in or Register to view URLs content!