Directional coupler

An HF plasma process excitation configuration includes an HF generator that is connected to a plasma load through a directional coupler. The directional coupler includes a transmission line, a first coupling line for detecting reflected power from the plasma load, and a second coupling line for detecting forward power from the HF generator, is the first coupling line is spaced apart from the transmission line and is terminated at least at one end with a termination resistance. The second coupling line is spaced apart from the transmission line and is terminated at least at one end with a termination resistance. Each coupling line has a predetermined and adjusted characteristic impedance, and the termination resistances each have a resistance value that corresponds within a tolerance to the characteristic impedance of the associated coupling line with a tolerance.