## 1 Introduction
[PERSON] et al. [14; 15; 16] conducted theoretical and numerical simulations on eddy current testing of CFRP, confirming that vertically oriented rectangular coil probes are more suitable for detecting delamination than pancake coil probes. They also established a coplanar dual rectangular coil finite element model for detecting delamination, which can be used for delamination detection. [PERSON] et al. [17] constructed a high-sensitivity eddy current testing system. They utilized this system along with a TR probe to achieve detection and imaging of 200 um delamination in CFRP at a frequency of 2 MHz. [PERSON] et al. [18] successfully detected 10 mm \(\times\) 10 mm delamination by optimizing the distance between the excitation coil and the detection coil. [PERSON] et al. [19] designed a high-speed eddy current probe that successfully detected delamination in CFRP plates at a frequency of 1 MHz and a speed of 4 m/s, meeting the requirements for high-quality detection. [PERSON] et al. [20] utilized a T-R probe to study the physical mechanism of delamination eddy current testing and conducted detection on delamination in CFRP with different ply orientations. The probes used in the above-mentioned literature were able to detect delamination in CFRP. However, due to the multi-phase heterogeneity and discontinuity in the geometric structure of CFRP, as well as the fact that delamination is an internal defect with relatively small eddy current disturbances, the detection results are susceptible to noise interference, and the probes currently used often have low detection sensitivity, which is not conducive to subsequent quantitative assessment of delamination. Therefore, designing a probe with higher detection sensitivity for delamination in CFRP has become an urgent issue that needs to be addressed. Pancake coil and rectangular coil are widely used in CFRP eddy current testing, with each type of coil having its advantages. Pancake coils can generate a uniformly distributed magnetic field, which aids in covering the entire testing area. A rectangular coil is directional and can produce a concentrated magnetic field, making defect localization easier. Additionally, rectangular coil probes can induce larger vertical eddy currents, which are more susceptible to disturbances caused by delamination. Therefore, this study designed a novel triple rectangular coil probe based on a rectangular coil. The excitation coils of this probe are dual rectangular coils, while the detection coil is a single rectangular coil. Using dual rectangular excitation coils can induce larger vertical eddy currents in the CFRP sample, thereby increasing the detection voltage. The spatially perpendicular arrangement of the excitation coils and detection coil reduces interference signals during detection and allows the detection coil to maximize the acquisition of defect information. Using COMSOL Multiphysics, a finite element simulation model was developed for CFRP delamination eddy current testing using the probe. Based on this model, an orthogonal experiment was carried out to determine the parameters of the probe, and the scanning modes of the probe were determined by studying the eddy current distribution in the CFRP sample. Subsequently, the influence of delamination of different dimensions on the detection coil voltage signal was studied. Finite element simulation models were established to simulate and calculate the detection voltage values of the novel triple rectangular coil probe, single pancake probe, and single rectangular probe for detecting different sizes of delamination. Based on this, the detection sensitivity of each probe was compared with verify the effectiveness of the designed probe.