Efficient RF Circuit Simulation Using an Innovative Mixed Time-Frequency Method

This paper suggests an answer to the problem of simulating heterogeneous wireless systems composed of baseband and RF blocks, as the former demand for SPICE-like engines, while the latter are more efficiently solved with frequency-domain tools as harmonic balance. The proposed time-frequency hybrid technique splits the circuit´s node voltages or mesh currents into fast and slowly varying state variables treating the former with the popular envelope transient harmonic balance technique and the latter with a pure time-marching engine. This way, the circuit´s hardest nonlinearities - and their rich harmonic content responses - are appropriately computed in the natural time domain, while the more moderate ones - and their corresponding smooth narrowband RF modulated signals - are efficiently processed in the frequency domain. Simulation tests performed in two illustrative application examples, revealed evident gains in computation speed over state-of-the-art RF simulation tools without any noticeable loss in accuracy.