Gate resistance influence on the impedance matching for common gate MOSFET amplifiers

The gate and bulk resistances influence on the impedance matching in case of MOSFET common gate amplifiers is investigated. It is shown that using a supplementary resistance of maximum 100Ω, S₁₁ becomes less than -15 dB over a wide frequency range, therefore making the circuit suitable for low power wideband RF applications and less sensitive to the loading capacitor value, at the price of a supplementary noise. The simulations were carried out in 0.35μm AMS CMOS process.