Metamaterials have become a hot research topic, especially in fields involving modern antenna structures. However, we still don't know much about what metamaterials are and their role in antenna development. In short, metamaterials refer to the combination of materials and structures that can realize unknown properties in nature. For example, the structured material coated on the surface of an object can refract light at an acute angle, thereby effectively hiding the object under the surface and making it invisible under certain wavelengths of light.
Since electromagnetic radiation (only high-frequency radiation) in radio frequency, microwave, millimeter wave communications, and radar follows the same physical laws as light, a similar effect can be achieved by adopting a structure suitable for electromagnetic radiation with longer wavelengths. For example, nano-scale metamaterials can be used to make negative refractive index materials, so millimeter-scale metamaterials can also be used to achieve various effects, including negative permeability or dielectric constant. The specific effect of metamaterials depends on the structural design, and usually only affects electromagnetic waves whose structure size is subwavelength.
Therefore, the use of modern manufacturing and processing technology can use semiconductor manufacturing technology to manufacture metamaterials, thereby affecting millimeter wave, terahertz and optical frequencies, or use common PCB copper structures to affect radio and microwave frequencies.
So far, researchers have created 2D metamaterial structures, metasurfaces, and various combined structures, and used them to achieve various effects, including making metasurfaces that refract the radio frequency and microwave energy around the structure, such as light. Refraction invisibility cloak. In addition, the researchers have also made radio frequency and microwave "lenses", which can focus and align radio frequency and microwave energy like optical lenses.
For RF and microwave engineers, it is more important that a new type of antenna design metamaterial structure has been developed. Compared with traditional antenna design, this type of metamaterial structure can greatly improve the performance of antenna structure, including split resonant ring structure, periodic structure, fractal structure and other metamaterial structures. They can be used to design with large gain and more Antenna with wide bandwidth and unique pattern. The key thing to note is that many metamaterial-enhanced antennas can be manufactured on planar support materials using low-cost electronic circuit manufacturing techniques. Therefore, modern panel antenna designs such as array antennas, cellular antennas and DAS can be used to achieve low-cost manufacturing of metamaterial antennas