Principles and Applications of Waveguide Transmission

1.5 EARLY HISTORY OF WAVEGUIDES That it might be possible to transmit electromagnetic waves through hollow metal pipes must have occurred to physicists almost as soon as the nature of electromagnetic waves became fully appreciated. That this might actually be accomplished in practice was probably in considerable doubt, for certain conclusions of the mathematical theory of electricity seemed to indicate that it would not be possible to support inside a hollow conductor the lines of electric force of which waves were assumed to consist. Evidence of this doubt appears in Vol. I (p. 399) of Heaviside's "Electromagnetic Theory" (1893) where, in discussing the case of the coaxial conductor, the statement is made that "it does not seem possible to do without the inner conductor, for when it is taken away we have nothing left on which tubes of displacement can terminate internally, and along which they can run." Perhaps the first analysis suggesting the possibility of waves in hollow pipes appeared in 1893 in the book "Recent Researches in Electricity and Magnetism" by J. J. Thomson. This book, which was written as a sequel to Maxwell's "Treatise on Electricity and Magnetism," examined mathematically the hypothetical question of what might result if an electric charge