Basic question on cassegrain antenna

[millimeter-wave]

What is the best reflecting coating for a cassegrain reflector antennas?

Was looking at this site to buy some but wondering if there are better coatings out there that make a difference?

https://www.miwv.com/cassegrain-reflector-antennas/

 

[vfone]

I am not an expert on this domain but from what I heard, gold plated aluminum is the choice for high frequency Cassegrain reflector antennas.
Most manufacturers don't specify this, they mention just aluminum reflector.
From what I understand the process is: first the aluminum is zincated, then copper plated, then gold plated.

**broken link removed**