We all know that a symmetric PCB stack-up is always recommended since it makes manufacturing easier and more reliable. However when designing PCB for antennas application this became quite a difficult constrain. For instance, let's consider a conventional patch antenna (maybe stacked for bandwidth reason) as radiating element in a phased-array. In this scenario we have very different requirements in terms of thickness since on one side of the PCB we have a patch antenna that requires fairly thick substrates but on the other side we have an RFIC which due to the ball-to-ball distance of the BGA packaging requires a thin dielectric so that manufacturer can drill vias that are thin enough to fit the BGA.
How do antenna designers overcame this issue? Are there some sort of best practice for this kind of situation? or should we just try to find a different radiating element that is more suitable?