A galvanically isolated, directional coupler, especially for in- and out-coupling of high-frequency measurement signals of a radar fill-level measuring device, wherein two mutually engaging, oppositely bent, conductive traces are provided, wherein the two oppositely bent, conductive traces are so arranged that that they couple with one another over a region of a quarter wavelength (λ/4) of the wavelength associated with the center frequency of the measuring signals and form two groups of laterally coupled, conductive traces, and wherein curved conductive trace portions adjoin each of the two groups of laterally coupled, conductive traces, in each case, over a region, which is less than an eighth wavelength (λ/8) of the wavelength associated with the center frequency.