The Research And Application Of Scattering Manipulation In Metamaterials

Scattering cancellation suppress the scattered field of original object by coating,while the scattering manipulation, a generalization of scattering cancellation, mimic the scattered field of another object. When this "another object" is the vacuum, the scattering manipulation degenerates into scattering cancellation. Using the scattering manipulation theory, the scattered field can be manipulated by changing the electromagnetic(EM) parameters of coating materials.Scattering manipulation has many potential applications. First, this method is applied into EM illusion device, and this device can change the scattered field of one object to that of another one with different EM parameters. This kind of EM illusion device can be used in military camouflage. In addition, scattering manipulation based illusion device enjoys superior properties, like isotropy and homogeneity of materials,when compared with that based on transformation optics. This makes it much more applicable in the realization. Besides, the impedance surface, a two dimensional surface, can also control the scattered field. By enclosing an original object with the impedance surface, the scattered field of this object can be controlled, including minifying and magnifying. The minifying of scattered field can be used in cloaking techniques, but this article mainly focus on the magnifying of scattered field, which leads to the realization of an antenna system. The impedance surface is homogeneous,and the radiation pattern of this antenna system can be changed by adjusting the surface impedance. In realization, this negative resistance surface can be realized by loading active elements. Furthermore, the surface impedance can be tuned by loading some variable elements, which means the radiation mode becomes tunable. The idea of scattering manipulation can also be used in the heat flux control, thereby realizing thermal illusion device. The homogeneous thermal conducting materials are used in designing this device, and the proposed device can camouflage a good thermal conductor into a poor one, vice verse. Thus, a thermal illusion is created with thisdevice that could be widely applied for thermal camouflage in the military. In addition,this method is very general, so it can be used to realize more kinds of thermal manipulation devices.