Embodiments provide a frequency selective surface (FSS). The FSS includes uniformly arranged FSS units. Each FSS unit includes a dielectric slab, a cross-shaped metal patch, and N square-ring metal patches. The cross-shaped metal patch is adhered to a first surface of the dielectric slab, and divides the first surface of the dielectric slab into four parts. Each part has a same size and a same quantity of the square-ring metal patches. The N square-ring metal patches are adhered to the first surface of the dielectric slab, and are arranged uniformly, and N is a positive integer power of 4. Lengths of the cross-shaped metal patch in two mutually perpendicular directions are equal, and both a length in each direction and a width of a gap between adjacent patches need to meet a specific condition.