Characterization of anisotropic electrical conductivity of carbon fiber composite materials by a microwave probe pumping technique

Abstract

Characterization of anisotropic conductivity of thin carbon fiber/poly ether ether ketone (PEEK) composite was investigated by noncontact and nondestructive microwave probe pumping (MPP) technique. The microwave was pumped by a coaxial probe, and the pumped field intensity distribution was measured by a near-field scanning microwave microprobe (NSMM) and a thermography camera. From the measurement and simulation results, it was observed that intensity of the electromagnetic field was higher along the high conductive directions due to the larger eddy current along these directions. Additionally, electrical defect detection by pumping probe technique was investigated. It was observed that the field intensity drastically decreased around the electrical defect. We showed that through an anisotropic field distribution around the pumping probe, an electrical defect of a carbon fiber/PEEK composite can be detected by combination of MPP and NSMM techniques.