Scientists Create Device That Turns Flat Surface Into Spherical Antenna
Scientists have created a new artificial surface that can bend and focus electromagnetic waves the same way an antenna does. The mechanism involves depositing an array of tiny metallic, U-shaped structures onto a dielectric material.
The breakthrough, according to researchers can lead to new types of antennas that are flat, ultra low-profile or conformal to shape of curved surfaces.
The new lens is an example of metasurface or metamaterial-an artificial material engineered in the lab that has properties not found in nature. When the same materials' surface are coated with tiny U-shaped elements, it acquires properties that mimic something known as a Luneburg lens.
The Luneberg lenses are equipped with unusual property that enables them to bend light more or less depending on where the light strikes the lens. The is possible because in such lens the index of refraction varies across the spherical lens body, differentiating with a normal lens. Luneberg lens can also focus light or incoming electromagnetic waves to an off-axis point at the edge of the lens.
Because of their properties, Luneburg lenses find a variety of applications as radar reflectors and microwave antennae. However, the spherical shape of a typical Luneburg lens is inconvenience in some applications, said researchers in the press release.
"We now have three systematical designing methods to manipulate the surface waves with inhomogeneous metasurfaces, the geometric optics, holographic optics, and transformation optics," said Tie Jun Cui of Southeast University in Nanjing, China, who fabricated the lens, in the press release.
"These technologies can be combined to exploit more complicated applications."
Developments related to research have been published in AIP Publishing's journal Applied Physics Letters.