054/A FFG Thread II

[Tam]

In the most straightforward implementation, beamwidth is a function of antenna aperture size and number of phase shifting elements. For small X-band arrays like the one on Type 054, the beamwidth is not going to be any narrower than the much larger S-band Type 346 array.

Even much larger X-band radars, like AN/TPY-2 with 25,000 T/R elements can perform volume search. If such a radar was not capable of adjusting its beamwidth, it would have a very hard time performing that function with a pencil beam less than 0,5 degree wide and all of that at a range of 1000km which severely limits the number of pulses than can be emitted.


Here's a plot of the radiation pattern for a of 12 element linear active array. in this case, each element is emitting at maximum power (gain=1).
View attachment 74847
Now, if the gain of each transmitting element is adjusted, a very different radiation pattern can be generated. Here's an example of a radiation pattern with binomial weighting of gain per transmitter
View attachment 74848
With binomial weighting beamwidth is more than doubled and sidelobes virtually eliminated. The downside is that this halves the antenna efficiency.

Here's a table of beamwidths, sidelobes and antenna efficiencty, per gain weighting method. As you can see, it is possible to further extend the beamwidth, up to 27.7 degrees.
View attachment 74846

If you have a small array, you're going to have a wider beam. Beamwidth is also a function of the frequency and you can shape the beam with an uneven distribution of power across the face. With AESA you can vary this pattern but in PESA, you have to build this through the feed design and in parabolics through a slightly uneven design of the parabolic.

You would think that removing the sidelobes would increase the antenna efficiency.

But enough this is out of topic.

These arrays will likely have search functions on their own as a collateral benefit. But they can never act as search primaries due to the limitations of range with X-band, and the power feed to these will also be limited, and the small size of the array limits their receiving gain. These kind of reminds me about the size of fighter radars, and the number of elements could be in the upper hundreds to over a thousand. RWS can still be in excess of 100km.

I also believe that these arrays will end up in the next gen frigate, 054B or 057, and it may end up embedded in an integrated mast.

But this is a hack on an existing ship, which already has in place, existing systems that will do search, and one that they want to get out fast through the gate with minimum modification. Its not a perfect situation and its not calling for perfection.

 

[SAC]

It will be important to determine the flight deck and hangar size of the new Type 054.

 

[iantsai]

A new Type 054A appears on the shipyard, not sure where it is, maybe at Huangpu shipyards.

 

[Tam]

That's Huangpu shipyard.

 

[para80]

Is this definitely a recent shot? It looks like it may be the first Huangpu-hull (launched a few weeks ago) back in about May? If it is, they progressed quite rapidly on this one or rather completely out of sight. I guess its possible if they can assemble two hulls one behind another?

A new Type 054A appears on the shipyard, not sure where it is, maybe at Huangpu shipyards.

 

[Tam]

If its on that side of the shed, then its the ship that's already launched..

If there is another ship, and there is another ship but we are not sure exactly what it is, it would be on the other side of the shed which is not visible in the photograph.

This picture, which is not complete as it is cropped to deny you showing the mast's upper section, on the far right of the picture, also gives a rare shot that the mast itself is built in two modular sections, a lower and an upper section.

 

[Tam]

To clarify what I was trying to say, the second ship should be the one behind the Type 056 corvette no. 596, and the ship on the right is the 31st that was launched recently. The ship behind 596 is still subject to confirmation by direct observation, but the shape of the bow and the bezel at the bow edge seems to point to another 054A.

 

[iantsai]

Is this definitely a recent shot? It looks like it may be the first Huangpu-hull (launched a few weeks ago) back in about May? If it is, they progressed quite rapidly on this one or rather completely out of sight. I guess its possible if they can assemble two hulls one behind another?

I saw this pic in another forum. Sorry I can't confirm it.

But I think it's possible to be true.

As we know, there're 12 vessels in this new batch of 054As for Huangpu.

Huangpu has a large shipyard and last time when it built 054As, it used a serial production line where there one vessel was fitting out, there were parts of another vessle being built.

So maybe after 054A #31 was launched into the Pearl River, the vessle which assembled inside recently was pushed out to the front of the shipyard so that there was space for a new vessle parts behind.

If there were new photos, I'll post them here.

 

[para80]

To clarify what I was trying to say, the second ship should be the one behind the Type 056 corvette no. 596, and the ship on the right is the 31st that was launched recently. The ship behind 596 is still subject to confirmation by direct observation, but the shape of the bow and the bezel at the bow edge seems to point to another 054A.

Thanks. Yes, it does appear to me this new image shows an 054A on the right hand side of the shed (from the photographers POV, left side from the ships direction). Admittedly that's my guess because the blurred stuff looks like vegetation. My only other idea was they can assemble two FFG in line one behind another, so this is still a new hull on the same track, but I havent looked at dimensions for that assembly hall to see if that is in fact feasible.

 

[Tam]

Thanks. Yes, it does appear to me this new image shows an 054A on the right hand side of the shed (from the photographers POV, left side from the ships direction). Admittedly that's my guess because the blurred stuff looks like vegetation. My only other idea was they can assemble two FFG in line one behind another, so this is still a new hull on the same track, but I havent looked at dimensions for that assembly hall to see if that is in fact feasible.

Yes there is a ship that appears on the right side of the shed, with the 31st frigate on the left side.

Both sides of the sheds have been used for 054A production in the past.

The side of the shed allows for both 056 and 054A to occupy the shed simultaneously.