Estimated colleagues,
Nice to get in contact again with all of you after a bit long time.
We are deploying a RF design and by first time we intend to use a multilayer pcb with different substrat thickness as shows the stack-up herebelow detailed.
Questions here are:
As per your experience, is it recomendable such a kind of substrat design? 
Some pcb provider reported it is very difficult to achieve. Can you recommend or share your background about pcb provider who can assure high reliability on this pcb provision?
Keep awaiting for your unvaluable feedback.
brgds, Ricardo
 
Ricardo Moncaglieri
QA Electronic Service Manager
INVAP SE
www.invap.com.ar