Qucs equation-defined and Verilog-A RF device models for harmonic balance circuit simulation

This paper is concerned with the development and evaluation of a number of modelling techniques which improve Qucs Harmonic Balance simulation performance of RF compact device models. Although Qucs supports conventional SPICE semiconductor device models, whose static current/voltage and dynamic charge characteristics exhibit second and higher order derivatives may not be continuous, there is no guarantee that these will function without Harmonic Balance simulation convergence problems. The same comment also applies to a number of legacy compact semiconductor device models. The modelling of semiconductor devices centered on non-linear Equation-Defined Devices and blocks of Verilog-A code, combined with linear components, is introduced. These form a class of compact macromodel that has improved Harmonic Balance simulation performance. To illustrate the presented modelling techniques RF diode and bipolar junction transistor macromodels are described and their Harmonic Balance performance simulated with Qucs and Xyce©.