Systems and methods are provided for improving fidelity of a quantum operation on a quantum bit of interest. In this way, occurrence of a large magnetic field outside the cable cores can effectively be reduced. The first end of the second antenna element is spaced apart from the second end of the first antenna element by a first air gap. The maximum cross-section of the openings amounts to 90 percent. In either case, the entire assembly may then be transported to a location on a lower level such as ground, for example, corresponding to the eventual installation location on the structure.