Trapped Surface Wave And Lateral Wave Along A Planar Conductor Coated With A Dielectric Layer

The exact analysis expressions of the electromagnetic fields generated by a vertical or a horizontal electric dipole in the air over or on a perfect or an imperfect conductor coated with a dielectric layer have been obtained in this thesis. And the electromagnetic fields generated by a horizontal electric dipole in the imperfect conductor have been discussed too. The author抯 studies is inspired from the academic arguments of Ronold W. P. King of Harvard University, Sheldon S. Sandier of the U. S. A. Northeastern University and James R. Wait of the University of Arizona in the field of radio-wave propagation. The main contributions of author抯 work are as follows: Firstly, The electromagnetic fields of a vertical electric dipole on a perfect conductor coated with a dielectric layer have been discussed. The properties and the characters of integral expressions of the electromagnetic field components are through analyzed. And according to the theory of complex function and the characters of the Bessel functions, the exact analysis expressions of the electromagnetic fields in the air on a perfect conductor coated with a dielectric layer have been derived. It is easily to evaluating the values of each filed components by these formulas. The debating problem between K&S (R. W. P. King and S. S. Sandier) and Wait is resolved by the author抯 studies. The author抯 conclusion also shows that K&S have overlooked that a trapped surface wave can be excited by the source for the case where the coating layer is a low-loss dielectric and the substrate is a highly conducting half-space in their paper But the conclusion of this thesis is that the trapped surface wave is derived from the residues of the poles of the integrands of the field components, and is not derived from the F(p) function. However Wait claims that the trapped surface wave is derived from the F(p) function, and will vary with ji? over a major distance range and its wave number is same as the wave number /c0 in the air. The relations between the wave number of the surface wave and the parameters of the dielectric are given in this thesis. The amplitude of the trapped surface wave in this thesis attenuate as p~?2 along the surface of dielectric, coincide with that of comments of Wait. The propagation wave number of trapped surface wave in this thesis is different to that in the comments of Wait, and it is neither the wave number ~ in the air nor the wave number k1 in the dielectric layer, but it is a value between k0 and k~ Furthermore, it correlates with the frequency f~ the permittivity e~., the III ? conductivity a and the thickness of the dielectric layer, and it is determined by the poles equation of integrand of these formulas. The conclusions of the author show that the number of poles of the integrand depends on the thickness of the dielectric layer and the wave number k1 in the dielectric. When in this condition as (n ?l)r < ?k~ 1