A theoretical study is presented to assess the performance of semiconductor superlattice (SL) multipliers as a function of the currently available input power sources. The prime devices that are considered as input power sources are Impatt diodes, InP Gunn devices, SL electron devices, and backward wave oscillator sources. These sources have been successfully designed to deliver input radiation frequencies in the range from 0.1 to 0.5 THz. We discuss the harmonic power generation of both odd and even harmonics by implementing an ansatz solution stemmed from a hybrid approach combining nonequilibrium Green’s functions and the Boltzmann kinetic equation.