In this paper, the possibility of using coaxial cables as
distributed strain sensors by time domain reflectometry is studied.
Analytical analysis is conducted on the relation between the distributed
axial strain and the change of characteristic impedance as well as on the
relation between the change of characteristic impedance and the voltage of
the reflected wave. The analysis leads to the establishment of the quantitative
relation between the distributed axial strains of a coaxial cable and the
change in the voltage of the reflected wave. It is demonstrated that the
voltage of the reflected wave can be used to measure the magnitude and
determine the location of the axial strains in a coaxial cable.
Furthermore, a good linearity is obtained when the axial strains are small.
The investigation highlights the potential of coaxial cables as distributed
strain sensors. Finally, the existing problems for such sensors are
discussed.