Experimental verification of a TE01 mode converter to locate a crack in a metal pipe

Abstract

In this study, a TE01 mode converter was developed to locate an axial crack on the inner surface of a metal pipe. Three-dimensional finite element simulation was conducted to evaluate the effect of inserted coaxial cables on the transmission characteristic of the mode converter. The result showed that the energy of TE mode microwaves leaned to transmit to one side when the cables penetrated with inclination. To demonstrate the effectiveness of the mode converter, experimental verification was conducted. The mode converter was fabricated based on the simulation result. Microwaves were emitted through the pipe wall of the converter to propagate on both sides (‘right side’ and ‘left side’) of a pipe with an artificial slit. Compared with the signals from each side, the reflection from the slit on the right side was more significant than that on the left side. This result is consistent with the numerical simulation result.