constante de acoplamiento
"Coupling Factor" is the ratio of an electromagnetic quantity, usually voltage or current, appearing at a specified location of a given circuit to the corresponding quantity at a specified location in the circuit from which energy is transferred by coupling.
Applicable units are those of quantitykind:CouplingFactor
http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=31891
http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=161-03-18
"Coupling Factor" is the ratio of an electromagnetic quantity, usually voltage or current, appearing at a specified location of a given circuit to the corresponding quantity at a specified location in the circuit from which energy is transferred by coupling.
For inductive coupling between two inductive elements, $k = \frac{\left | L_{mn} \right |}{\sqrt{L_m L_n}}$, where $L_m$ and $L_n$ are their self inductances, and $L_{mn}$ is their mutual inductance.