Embodiments of the present invention relate to an electromagnetic wave beam splitter, comprising a functional layer made of at least one metamaterial sheet, wherein different metamaterial sheets have the same refractive index distribution; the metamaterial sheet may be divided into a circular region and an annular region concentric to the circular region; a refractive index increases continuously as a radius increases and refractive indices at the same radius are the same within the circular region; and a refractive index decreases continuously as a radius increases and refractive indices are the same at the same radius within the annular region. The circular region of the functional layer of the beam splitter according to the present invention has the function of diverging an electromagnetic wave; the annular region has the function of converging an electromagnetic wave; the electromagnetic wave incident on the circular region of the functional layer deflects toward edges on two sides of the functional layer respectively; the electromagnetic wave incident on the annular region deflects in a direction toward a circle center; and after an electromagnetic wave emitted by a signal source is incident on the beam splitter, an emergent electromagnetic wave forms an annular radiation region. This can satisfy the requirements of, for example, avoiding an obstacle and interference.