US Patent 7525397 Stripline directional coupler having a wide coupling gap

The provided stripline directional coupler, having two coupling conductors galvanically isolated with respect to a grounding layer at zero potential, includes, in particular, a multilayer conductor pattern having at least three metallic layers separated by at least two dielectric insulating layers; a first metallic layer forming the coupling conductor, and a second of the at least three metallic layers having a conductor pattern, which is galvanically isolated from the at least two other metallic layers, and with the aid of which capacitors that are connected in series and are very small are formed between the at least three metallic layers.