Re: Help in understanding the paper "Understanding Wide-band MOS transistors"
Re 2: There is always a technology gain-bandwidth product
which is your ultimate limit, even if you've done your best
with the rest of the circuit optimization.
A lineup that uses (say) one A=100 amplifier in a fmax=100GHz
technology will probably give you a 1GHz BW.
A lineup that uses the same technology, cascaded A=10 stages
(A=100) but each stage having 10GHz BW, will have a A=100,
BW 10GHz (-ish) but a 2-pole rolloff rather than 1-pole. This
could be good or bad, depending on what you wanted to
happen to incoming and locally generated harmonics, but
probably better than 1GHz BW (especially if you wanted 2GHz
passband).