Verification of a frequency dispersion model in the performance of a GaAs pHEMT travelling-wave MMIC

The impact of frequency dispersive effects on typical figures of merit is investigated in a distributed MMIC realized in 0.15 /spl mu/m GaAs pHEMT technology. A novel compact dispersion model, allowing for accurate simulation of both static and dynamic multiple time constant IV characteristics, is employed. In a comparison of measurement and simulation, the model is both validated and used to quantify and interpret the error introduced when neglecting frequency dispersion in the design of MMICs. Device operation is investigated with respect to gain, linearity and power-added efficiency, all of them affected by dispersion effects. The model is shown to significantly improve simulation accuracy by increasing the validity range in terms of the frequency- and voltage regimes.