Patent ID: 7157972

Claim:
A radio-frequency amplifier comprising: a transistor having an input terminal, an output terminal, a control terminal, and a transconductance g m ; a series-connected feed-through impedance connected in parallel with the input terminal and the output terminal of the transistor; a load resistance R L connected to the output terminal of the transistor; and wherein the control terminal of the transistor is biased at a fixed voltage, and the transistor and a signal source impedance r s satisfy the equation: g m = 1 R s ⁢ ( δ ⁢ ⁢ α γ ⁢ ( 1 + χ ) 2 ⁢ η ⁡ ( ω 0 ) + η 2 ⁡ ( ω 0 ) ) - 1 2 where δ=a gate noise coefficient of the transistor, α=a ratio of g m to a channel conductance at zero drain-to-source voltage of the transistor, g d0 , γ=a channel thermal noise coefficient of the transistor, χ=a ratio of a backgate transconductance g mb of the transistor to g m , ω 0 =an operation frequency, and η(ω 0 )=a ratio of a gate admittance g g of the transistor to g m .