Peano-Meander Curve Based Microwave Array Sensor for Nondestructive Testing of CFRP Composites

In this paper a novel Peano-Meander curve-based microwave array sensor is designed for Non-destructive Testing (NDT) of Carbon Fiber Reinforced Polymer (CFRP) based composites. The proposed array sensor is designed by making use of affordable Taconic TLY-5 material. Moreover, the transmission coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left(\text{S}_{21}\right)$</tex> response and electric field distribution of this sensor are analyzed to examine the performance of this sensor. The suggested sensor functions as a bandstop and bandpass filter in the presence and absence of cracks, holes or deformation on the surface of Sample Under Test (SUT). A fringing field sensing capacitor (FFSC) serves as a “sensing pad” in the proposed Peano-Meander curve-based unit sensor, which contacts directly with the SUT to sense surface cracks. The designed sensor can detect the minimum crack size of 0.5 mm while operating in the frequency range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{0. 2 5 - 2. 7 5 ~ G H z}$</tex>. This sensor may be used to identify surface cracks to improve the safety and integrity of crucial infrastructure, such as bridges, pipelines, and airplanes.