Metamaterials in Antenna Applications: Classifications, Designs and Applications

Abstract

Recently the ancient Greek prefix, meta (means “beyond”), has been used to describe the composite materials with unique features that do not exist in the nature [1]. Reviewing the literature, it appears that various terminologies have been used to classify metamaterials depending on their applications. As an example, “double negative (DNG) material” refers to those materials with effective negative permittivity and permeability, which results into properties such as left-handed (LH) wave propagation and negative index of refraction (NIR). Periodic structures that prohibits the propagation of electromagnetic waves in a certain frequency band for certain arrival angles and polarization senses are classified as electromagnetic band-gap (EBG) structures. Another important category of metamaterials consist of ground planes that exhibit unique reflection characteristics other than conventional PEC, and are defined as “artificial complex ground planes”. Fig. 1 shows the three basic categories of metamaterials, with some representative applications illustrated. This invited-talk paper summarizes the results published by the author and his co-workers on this subject, with most examples addressed on the design and analysis of metamaterials for antenna applications.