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common source amplifier of RF signal problem

yefJ

Hello,my input signal is 3GHz and 0.3V i need my signal to be at least 0.7,so i built a common source amplifier by the principle of the schematics bellow.

as you can  see,from my operating point simulation i have gm=10.48m my Rd=1K from the formula bellow A=gmRd ,so  it needs to amplify my signal 10 times.

instead the signal is decreased as shown in the transient  plot bellow.where did i go wrong?

maybe it's the output port putting impedance that i am not aware of?

Thanks

Parents

  • You have the gate of the transistor fixed at 700mV, so there is very little influence of the sinusoidal input source to the left of the capacitor (other than because of charge sharing between the input cap and the capacitances from the gate within the transistor. 

    I assume you didn’t mean to hold the gate firmly at a fixed DC voltage when biasing it. 

    There’s no output port in the circuit so there won’t be any load impedance due to a “port”.

    Andrew

  • in reply to Andrew Beckett

    Thank you very much Andrew, the DC source imposed voltage without letting the AC source to have its influence,i tried Adding a resistor and it worked.

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