  We demonstrate that directional electromagnetic scattering can be realized
from a artificial Mie resonant strcuture which supports electric and magnetic
dipole modes simultaneously. The directivity of the far-field radiation pattern
can be switched by changing the incident light wavelength as well as tailoring
the geometric parameters of the structure. Particularly, the electric
quadrupole at higher frequency contribute significantly to the scattered
fields, leading to enhancement of the directionality. In addition, we further
design a quasiperiodic spoof Mie resonant structure by alternately inserting
two materials into the slits. The results show that multi-band directional
light scattering are realized by exciting multiple electric and magnetic dipole
modes with different frequencies in the quasiperiodic structure. The presented
design concept is general from microwave to terahertz region and can be applied
for various advanced optical devices, such as antenna, metamaterial and
metsurface.
