Fig. 1. Distribution of points and interpolation nodes in cubic spline field of convex quadrilateral element

Fig. 2. Quadrilateral meshing of square resonator

Fig. 3. Eigen frequency of different modes

Fig. 4. Variation of relative error with mesh size

Fig. 5. Relative error of (4,1) mode with mesh size(4,1)模式下相对误差随网格尺寸的变化

Fig. 6. Square vacuum cavity: component of six resonant modes六种共振模式下分布

Fig. 7. Error comparison of numerical results with reference values at measuring point

Fig. 8. Comparison of numerical results and reference results of different monitor points

Fig. 9. Distribution of electromagnetic wave propagating to the right boundary of total field

Fig. 10. Comparison of mesh distribution