[dustinchilson]

It's a Faraday cage (https://en.wikipedia.org/wiki/Faraday_cage), It keeps external radio signals out so they can check for EMI (https://en.wikipedia.org/wiki/Electromagnetic_interference)

[JorgeGT]

This is partially incorrect. The objective is not only to isolate the device from external radiation but to avoid internal RF reflections within the chamber. That's why the geometry of the wedges, which are covered in a RF-absorbent material. A Faraday cage wouldn't help with this.