The MFSA was designed on the basis of the second kind of MF levitation principle. Fig. depicts the main structure and dimensions of the MFSA, while the values of the main structural dimensions of it were listed in Table . From the image processing results of the SEM images, it can be seen that most of the surface protrusions of the tree frog's toe pads are hexagonal. Therefore, we believed that the hexagon is the main factor affecting the surface function of the tree frog, and the hexagonal structure was added on the inner surface of the MFSA.