cmetal shim for quartz substrate

what is the corrugated metal shim between quartz substrate and the metal box in attached picture?The thickness of shim is 0.15mm.I think it's aluminium plated by gold.But how the corrugated shape be made?where can I buy it?Thanks!

That is a new one on me! Quartz has an odd expansion coeficient. Maybe the mesh is a means of attaching the quartz substrate to ground without it popping off over temperature?

yes,I think it's a buffer layer between quartz and box for quartz is very Fragile .
but how the corrugated shape be made?

It looks a little coarse. I have seen much finer gold meshes from companies like Englehard. As I recall, quartz matches stainless steel (you should double check that) in expansion coefficient, so if you have an aluminum or brass fixture it will be hard to epoxy quartz onto it. But this mesh looks sooooo funky, I doubt it has good electrical properties anywhere above a few GHz. I would instead work on getting a temperature coefficient match between housing and substrate and just epoxy it down.

The picture has been enlarged for nearly 5 times,the mesh is very fine indeed.The
electrical properties below 18 GHz has no problem!The metal of box is brass plated with gold.

And how exactly do you know that "The electrical properties below 18 GHz has no problem!". Looks to me like you will have all sorts of resonance effects, starting around 15 Ghz or so, but since you are only measuring a one-port you probably do not realize this. Have you tried measuring something simple like a 50 ohm load to 26 Ghz?

Yes,because it's the mixer product of HP.