Transmission coefficient of a lengthy nanoribbon with M = 9. There are two impurities in the form of an electric dipole (with on-site energies ±1.5 eV) in a small part of the nanoribbon (central wire). The locations of the impurities are distinguished by two integer numbers (see Fig. 1 for better understanding of the coordinates). The other on-site and hopping energies of the system are taken as ε₀ = 0 and β = 1 eV, respectively.