Signal propagation in electron waveguides: Transmission-line analogies

Signal propagation along an electron waveguide with a nearby screening metal plane is investigated. It is mediated by one-dimensional intrasubband plasma oscillations or space-charge waves. The signals therefore propagate much slower than the velocity of light. A transmission-line model and a characteristic impedance are theoretically derived. Discontinuities (changing width of an electron waveguide, junction to a bulk conductor, and elastic electron scatterer) are modeled as changes in characteristic impedance and insertions of equivalent series elements. In the limit of short waveguide sections, the two versions of the Landauer formula for conductance G=G(0)T and G=G(0)T/(1-T) are obtained. In the limit of many subbands, the velocity of light is reached.