The present invention relates to an antenna, which includes a feeding part and a radiating part. By using the feeding part and the radiating part that are perpendicular to each other and use dielectric substrates, not only a volume of a normal radiation antenna is reduced, but also a substrate integrated waveguide directly radiates energy outwards, thereby improving operating bandwidth of the antenna.

According to one embodiment, a waveguide bend includes a metal block. The metal block includes a first waveguide, a second waveguide and a third waveguide. The first waveguide, the second waveguide and the third waveguide are integrally formed. The second waveguide includes a bend at which a propagation direction of a radio wave is changed. An opening size of the second waveguide is smaller than an opening size of the first waveguide. The third waveguide is provided between the first waveguide and the second waveguide. An opening size of the third waveguide is smaller than the opening size of the first waveguide and is larger than the opening size of the second waveguide.

A waveguide disclosed herein may be implemented as a hollow irregular hexagonal metal structure which receives an electromagnetic signal and propagates the signal through the hollow hexagonal metal structure. The waveguide may be fabricated using metal additive manufacturing techniques and include one or more downward facing and unsupported surfaces.