The book covers various numerical field simulation methods, nonlinear circuit technology and its MF-S- and X-parameters, as well as state-of-the-art power amplifier techniques. It also describes newly presented oscillators and the emerging field of GHz plasma technology. Furthermore, it addresses aspects such as waveguides, mixers, phase-locked loops, antennas, and propagation effects, in combination with the bachelor's book 'High-Frequency Engineering,' encompassing all aspects related to the current state of GHz technology. Content Waveguides (Fundamentals) Basics of field simulation (Free-space simulation, Numerical field simulation) Fundamentals of nonlinear RF technology (Nonlinear simulation methods) Introduction to Mixed-Frequency S-parameters (X-parameters, Harmonic Radar) Power amplifiers (Classical operating modes A, AB, B, and C, Circuit concepts of power amplifiers, D to S operation, Configurations of power amplifiers) Oscillators (Two-port oscillators, Single-port oscillators) Detectors and mixers (Single-sideband converters and IQ modulators) Phase-locked loops and synthesis generators (ΣΔ-Fractional-N synthesis generator) Technically generated plasmas (GHz Plasma jets, Lamps, Spark plugs, Scalpels, Decoupled plasma) Antennas (Fundamentals, Array antennas) Propagation (Fundamentals) The author Prof. Dr.-Ing. Holger Heuermann teaches and conducts research at IMP at FH Aachen.