## 5 Conclusions  
This paper presents a novel triple rectangular coil probe designed for detecting CFRP delamination. The structure of this probe reduces the direct mutual inductance between the excitation coils and the detection coil, thereby minimizing the impact of interference signals. This design allows the detection coil to capture defect information to the greatest extent possible, thereby improving detection sensitivity and facilitating delamination inspection. The main conclusions are as follows:  
1. The designed probe has different scanning modes for CFRP samples with different layers. When the direction of the excitation current is consistent with the direction of the fibers, the detection effect of the delamination is optimal. 2. The designed probes can sensitively detect delamination from both the top and bottom surfaces of the CFRP sample, including those located deeper within the sample. In the detection of delamination with different lateral dimensions, the relative position of the probe varies when the detection voltage difference rises and falls. The larger the lateral dimension, the further forward the probe's relative position during voltage difference rise and the further backward during voltage fall. By studying the relative position of the probe during voltage difference rise and fall, quantitative detection of the lateral dimension of delamination can be achieved. For delamination of different thicknesses, the size of the detection voltage difference peak varies. Through studying the detection voltage difference peaks that occur during the detection process, quantitative detection of the thickness of delamination can be achieved, providing valuable quantitative analysis references for CFRP delamination detection. For detecting multiple defects within the CFRP sample, the designed probes can successfully detect them, but determining the dimension of the defects based solely on their detection signals can be challenging. However, combining the results of top and bottom scans can provide a rough estimation of the dimension and location of the delamination. 3. Under the condition where the dimensions and number of turns of the excitation coils are the same for all three probes, when the lateral dimension of delamination changes by 5 mm, the sensitivity of the single pancake probe and the single rectangular coil probe is only 88.24% and 72.55% of that of the novel triple rectangular coil probe. When the delamination thickness changes by 0.5 mm, the sensitivity of the single \begin{table}
\begin{tabular}{c c c} \hline \hline
**Probe Types** & _Sensitivity_**1** & _Sensitivity_**2** \\ \hline Single pancake probe & 0.0090 (V/mm) & 1.4809 (V/mm) \\ Single rectangular probe & 0.0074 (V/mm) & 1.7120 (V/mm) \\ Novel triple rectangular coil probe & 0.0102 (V/mm) & 3.0200 (V/mm) \\ \hline \hline \end{tabular}
\end{table} 
Table 11: The sensitivities of different probes. pancake probe and the single rectangular coil probe is only 49.04% and 56.69% of that of the novel triple rectangular coil probe. In conclusion, the probe proposed in this paper is feasible and effective for detecting CFRP delamination and meets the demand for high-sensitivity detection. This probe has guiding significance for the design and development of probes for CFRP delamination eddy current testing and provides valuable references for the quantitative evaluation of delamination in CFRP eddy current testing. Conceptualization, Y.Z. ([PERSON]) and B.Y. ; methodology, Y.Z. ([PERSON]); software, Y.Z. ([PERSON]); validation, Y.Z. ([PERSON]), H.C., and B.Y. ; formal analysis, Y.Z. ([PERSON]), Y.Z. ([PERSON]), and Z.Z. ; investigation, Y.Z. ([PERSON]); resources, B.Y. ; data curation, Y.Z. ([PERSON]) and H.X. ; writing--original draft preparation, Y.Z. ([PERSON]); writing--review and editing, B.Y. ; visualization, B.Y. ; supervision, B.Y. ; project administration, B.Y. ; funding acquisition, B.Y. All authors have read and agreed to the published version of the manuscript.