An investigation of IM3 distortion in relation to bypass capacitor of GaAs MMIC's

IM3 distortion in relation to a bypass capacitor of a GaAs MMIC has been investigated. Through non-linear simulation and the measurement of a 1-stage MMIC amplifier, it was shown that only IM3 performance depended on the bypass capacitor. A new analytical model of IF amplitude modulation for the 2-tone RF carrier outputs is proposed. Based upon this model, the RF carrier outputs were distorted from the amplitude modulation by IF of the 2-tone carriers when the output matching circuit was of high impedance at the IF.