**1. Introduction**

In the modern society, we are surrounded by an amazing variety of materials, such as polymers, ceramics, composites, high strength alloys, superalloys, and so on. Naturally, existing materials possess some properties. However, one can change or modify the naturally occurring properties by altering the microstructure of the materials. The resultant materials are also called as the engineered materials. Recently, the engineered materials have gained much attention by researchers. The engineered materials exhibit better performance, such as large cyclic life, broad temperature ranges, lighter in weight, etc., than conventional materials. There exist numerous engineered materials such as metal-matrix composites, polymer-based composites, piezoelectric materials, magnetostrictive materials, metamaterials, etc. Owing to their large lifetime and high performance, these materials are significantly used almost in all fields of science and engineering. In this article, we have focused on metamaterials and their applications.
