Variations of characteristic impedance along short coaxial cables

Variations of characteristic impedance along short coaxial cables

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A method is described for determining the local characteristic impedance at any point on a high-frequency coaxial cable. Measurements are made of the deviations from a harmonic series of the resonant frequencies of a short length of open or short-circuited cable. It is shown how these deviations can be used to calculate the coefficients of Fourier series describing the impedance variations along the length. Since the measurements are performed at microwave frequencies, the resolution of the impedance changes is considerably better than for lower-frequency methods.Measurements on an artificially discontinuous cable have allowed the experimental accuracy of the method to be determined, and close agreement has been obtained between the experimentally predicted and the actual impedance changes.Results from short cable samples indicate that the local variations of characteristic impedance are largely due to changes in the diameter over the dielectric filling.


    1. 1)
      • M. Didlaukis , H. Kaden . Die inneren Ungleichmässigkeiten von koaxialen Breitbandkabeln. Elektrische Nachrichten-Technik
    2. 2)
      • P. Merz , W. Pfleger . Irregularities in Broad-Band Wire Transmission Circuits. Bell System Technical Journal
    3. 3)
      • L.N. Brillouin . Irregularities in Telephone and Television Coaxial Cables. Electrical Communication
    4. 4)
      • Clarke, W.W.H., Hinchliffe, J.D.S.: `The Evaluation of Cable Irregularities at Very High Frequencies', Monograph No. 75 R, Proceedings I.E.E., September 1953, 101, p. 55, Part IV.
    5. 5)
      • Rosen, A.: `The “Unit” Treatment of Impedance Irregularities and its Application to Long Lines', Monograph No. 98, Proceedings I.E.E., May 1954, 101, p. 271, Part IV.
    6. 6)
      • L. Parcé . Paires concentrique pour hautes fréquences. Annales des Postes, Téléegraphes et Téléphones
    7. 7)
      • M. Cotte . La détermination des écarts d'impédance locale dans un câble et de la function de correlation de ces écarts. Bulletin de la Société Française des Électriciens
    8. 8)
      • M. Cotte . Éitude d'une longueur de fabrication de câble par des mesures d'impédance terminale. Câbles et Transmission
    9. 9)
      • H. Kaden . Über ein Verfahren zer Messung von Breitband-kabeln. Telegraph und Fernsprechtechnik
    10. 10)
      • Roberts, F.F.: `A Pulse Test Set for the Measurement of Small Impedance Irregularities in High Frequency Cables', Paper No. 736 R, Proceedings I.E.E., January 1949, 96, p. 17, Part III.
    11. 11)
      • W.R. MacLean . The Resonator Action Theorem. Quarterly of Applied Mathematics
    12. 12)
      • Whinnery, R., Jamieson, H.W.: `Coaxial Line Discontinuities', Proceedings of the Institute of Radio Engineers, 1944, 32, p. 695.
    13. 13)
      • Jackson Willis . (1945) , High Frequency Transmission Lines.
    14. 14)
      • W.T. Blackband , D.R. Brown . The Two-Point Method of Measuring Characteristic Impedance and Attenuation of Cables at 3000Mc/s. Journal J.E.E.

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