Theoretical study of dielectric cables

Earlier investigations by the author indicated that certain waves were formed only in dielectric guides [see Abstract 1936B03275] with a high degree of symmetry (square or circular section). Some confirmation has been obtained from the work of later investigators, but no detailed determination of the types of waves and propagations in rectangular or elliptical tubes. Certain types of waves are little affected by changes in cross section, but others are influenced both in structure and in laws of propagation. Waves of the first type are likely to propagate without variation in tubes that are only slightly irregular, but waves of the second type undergo reflexions and changes of wave type with loss of energy for each irregularity in form or each bend in the tube. The use of such waves would involve strictly prescribed operating conditions. Starting from the general form of propagation equations, the author examines the particular form of progressive waves, the characteristics of waves of electric and magnetic types, and transmission phenomena in rectangular and elliptical conductors with waves of various types. Charts are presented summarising the results of the investigation and showing the types of waves realisable in a circular tube. Comparisons are drawn with similar acoustical problems.