Three Port Stability Analysis of Broadband Millimetre Wave MMIC Amplifier

The stability of microwave amplifiers is normally analysed as a two port network. An amplifier has at least a third port for biasing that might be considered for stability. Bias line impedances can lead to oscillations in amplifiers. Full stability analysis of a millimetre wave MMIC amplifier has been carried out using a three port Scattering parameter test. Bias line impedance conditions to assure stable operation have been obtained.