Composite Metamaterials: Classification, Design, Laws and Future Applications

*Tarek Fawzi and Ammar A.M. Al-Talib*

## **Abstract**

The development of science and applications have reached a stage where the naturally existed materials are not meeting the required properties. Metamaterials (MMs) are artificial materials that obtain their properties from their accurately engineered meta-atoms rather than the characteristics of their constituents. The size of the meta-atom is small compared to light's wavelength. A metamaterial (MM) is a term means beyond material which has been engineered in order to possess properties that does not exist in naturally-found materials. Currently, they are made of multiple elements such as plastics and metals. They are being organized in iterating patterns at a scale that is smaller than wavelengths of the phenomena it influences. The properties of the MMs are not derived from the forming materials but their delicate size, geometry, shape, orientation, and arrangement. These properties maintain MMs to manipulate the electromagnetic waves via promoting, hindering, absorbing waves to attain an interest that goes beyond the natural materials' potency. The apt design of MMs maintains them of influencing the electromagnetic radiation or sound in a distinctive technique never found in natural materials. The potential applications of MMs are wide, starting from medical, aerospace, sensors, solar-power management, crowd control, antennas, army equipment and reaching earthquakes shielding and seismic materials.

**Keywords:** metamaterials, permittivity, permeability, electromagnetic wave, hyperbolic, chiral, transmission matrix, reflection matrix, anisotropic

#### **1. Introduction**

Metamaterials are synthetic composite structures with peculiar material characteristics. They have protruded as a promising material for several science disciplines comprising physics, chemistry, engineering, and material science. MM has been described as structures designed according to an imposed geometry to be exploited in a definite application. The characteristics of MMs are derived from the microstructure, inherent properties, architecture, and the features'size within it. The 3D architecture can substantially substitute some material characters such as photonic band-gaps, negative thermal expansion, negative Poisson ratio and negative refractive indices [1].

The fabrication of composite metamaterials (CMMs) enables the manipulation of the microstructure and the novel geometry resulted in new or developed

properties which were never found in bulk materials. Also, CMM expands the design space occupied by MM [1]. The industrial applications incorporated MM and CMM in lightweight materials, micro-electromechanical systems, sensors, energy storage and photovoltaic.
