Closed-loop stability analysis of microwave amplifiers

Abstract

A stability analysis technique of microwave amplifiers, valid for large- or small-signal regimes, is presented. The technique calculates the system poles and zeroes from a closed-loop frequency response of the circuit linearised around its steady state. The method has been applied to an S-band monolithic amplifier, detecting spurious oscillations for certain specific bias conditions and input power levels, in good agreement with measurements.