liu6747
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Portland, OR
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On Thomas Lee's RF Book, 2nd Ed, Sec 12.3 page 375, he says:
".. both vacuum tubes and MOSFETs are devices with nominally capacitive input impedances. The key word, however is " nominally". for if the input impedances actully were purely capacitive then the input could never consume any power, and the power gain would necessarily be infinite even at infinitely high freq, sunch result defires common sense..."
Why the pure capactive input will have infinite gain? in such case S11=0dB all input power will be reflected back to source and output = 0, gain= - infinite dB. I like Lee's book and I believe he is right, but anyone can point out why I am wrong or there is something I missed?
Thanks
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