Second order extension of power amplifiers behavioral models for accuracy improvements

In the design process of reconfigurable radars, it is required to study the interaction between antennas and the power amplifiers in order to quantify the distortion and predict the performances of power amplifier (PA) on TX-chains. This paper presents an accurate behavioral model for PAs, based on nonlinear scattering functions, which allows taking into account large output loading impedance mismatches, i.e. Voltage Standing Wave Ratio (VSWR) up to four. First application presented is a black box modeling technique limited to Taylor first order expansion dedicated to moderate VSWR (VSWR ≤ 3). Unfortunately, the first order model is not efficient enough, so a second application is presented, showing an accurate model expanded to Taylor second order in the case of large VSWR (VSWR > 3) which allows predicting circuit performances at system level and establishes a mixed simulation tool for a bilateral communication between amplifiers and antennas.