measure the the power gain of the transistor , and sweep it with bias current , coz it is bias dependent , find wen the power gain is unity , this is the fmax
hi,
as you have said that ft is the unity current gain bandwidth (point where current gain drops to 0 or 1dB).
Now my question is whether it will be the same as unity power bandwidth (frequency at which power gain drops to 0.) I am assuming power is the product voltage and current.
So if current gain is zero, so that should mean that power gain is also zero?
Please give some clarification
I said that current gain is unitary not zero (zero in dB)
Next if you talk about product of current and voltage you have also to consider where the product is computed (i.e on the load? On the active device? ... ) and the loading conditions
h21 means that the load is a short circuit
Furthermore I stated "unilater power" gain and not power gain... make a search in google for its definition