This is a type of mixed material multilayer PCB built on 20 mil RO4350B plus FR-4 substrate for the application of satellite antenna.
It's 1.69 mm thick, no silkscreen, no solder mask on both sides and immersion gold is plated on pads and tracks.
The base material is used from Rogers and ITEQ, entire board supplying 1 PCB up.
They're fabricated per IPC 6012 Class 2 using supplied Gerber data. Each 25 boards are packed for ship.