自己在用CST建模仿真(unit_cell+open边界)时,发现从介电为5.5的光密介质向介电为1的光疏介质中斜入射时,若入射角超过了临界角,软件会报错“The material in port Zmax corresponds to a scan angle outside the visible space. Please change the background material to the material with the lowest product of relative permeability and relative permittivity (the lowest refraction index), or use periodic boundaries with the phase specified rather than the scan angle”。尝试了很多种方法,但都没有成功。请问大家遇到过类似问题么?应该如何解决呢??万分感谢!!