In the process of designing a broadband RF amplifier, I've come across some commercial boards, claiming gain flatnesses of +-1db from DC to 1Ghz. Those boards are ridiculously simple, having only one or two transistors and, in some of them, almost no matching on either side.
See for example this one:
It doesn't have input bias, no matching, no nothing, beside DC power and chokes.
Despite the simplicity, the specs claim 64db of absolute flatness from DC to 1Gz, and they even show a graph of S21 showing it.
How is it possible to archive such impressive performances with those simple circuits?
Are the active devices internally matched and biased?
Or are all those boards nothing but chinese fakery.