Theoretical Models of Metamaterial

Metamaterials have growing attention for the past few decades in scientific societies. Although metamaterials can be acknowledged as left-handed substances otherwise materials having a negative value of the refractive index. To get the required response to electromagnetic metamaterials by way of sub-wavelength resonant structures can be artificially engineered. On the other hand, features of natural materials remain inadequate as a result of their chemical configurations and constructions. Unit cells known as meta-atoms are used to control the optical activity of metamaterials. In metamaterials, many unusual advances have been proposed, including negative value, the refractive index, cloaking, perfect absorber, etc. To comprehend the fundamental physics of metamaterial (MTMs), several theoretical models or theories have been introduced. Each model is abstractly distinct and yields characteristic equations and assumptions. This chapter reviews the meta-materials’ theoretical models, including lumped equivalent circuit model, theory of effective medium, transmission-line theory, coupled-mode concept, and interference model in addition Casimir-Lifshitz theory. The theoretical methods offer an understanding of MTMs from dissimilar points of opinion. Models have their separate benefits and drawbacks.