2. Electromagnetic composites

Electromagnetic composites are generally systems made up of several components. Most often, they consist of a dielectric, semiconductor or metallic matrix, which determines their mechanical and thermal properties, and inclusions that modify the electromagnetic properties of the whole. Let's not forget that the concept of composite materials is actually very old. Cathedral windows and the colored glass of antiquity were already composite materials. The inclusions are generally very small compared with the wavelength of use, except in the case of certain structures known as frequency-selective surfaces. They can be arranged randomly in the matrix, as in stained glass, or periodically, as in crystalline materials. A random arrangement generally results in a single type of property, whereas a periodic arrangement allows specific properties to be obtained as a function of wavelength and direction...