An electromagnetic model of a “potential barrier” may be constructed from three sectors of waveguide, two outer sectors being filled with dielectric, the short inner sector air-filled. Using the mathematical analogy between the propagation data of the De Broglie wave and the wave inside a waveguide—above and below cutoff—it is demonstrated that, for a frequency of operation between the cutoff frequencies of the air-filled and the dielectric-filled waveguide, the air-filled section represents the potential barrier region. Thus the described apparatus, the construction of which has been carried out in full detail, enables the modeling of the tunnel effect experimentally and in a quantitative fashion.