On the Transmission Line Analogy for Modeling Plasmonic Nanowire Circuits

Modeling slot waveguides using the analogy with transmission lines in microwaves proved itself to be an accurate and simple method for characterizing plasmonic field propagation. Here, the possibility of generalizing the applicability of this method to plasmonic circuits consisting of nanowires is analyzed. It is found that it can be applied as long as the circuit can be divided in regions with known transverse field distributions and propagation constants, the total matrix characterizing plasmon propagation being composed of propagation and interface matrices, as in slot waveguides, the elements of the latter being, however, defined in terms of butt-coupling transmission coefficients at the interface and not using the simple characteristic impedance expression used for slot waveguides.