Artificially designed and structured electromagnetic materials, also known as metamaterials (MMs), allow the engineering of exotic electromagnetic properties, which in turn offers control over various wave-matter interactions, such as refraction, absorption, and radiation. Most reported MMs, both in the microwave and optical ranges, are limited either by a narrow bandwidth of operation and/or by significant absorption loss, both of which impede their integration into practical devices. By overcoming such limitations, broadband and low-loss MMs have the potential for providing great benefit to various engineering disciplines, especially for microwave antennas and circuits. This chapter presents the recent progress on advanced antenna designs by incorporating wideband and low- loss MMs with custom engineered anisotropic electromagnetic properties. First, an ultra-thin anisotropic MM coating is presented, 2which enhances the impedance bandwidth of a monopole to over an octave while simultaneously preserving the desirable radiation pattern properties. Next, static broadband anisotropic MM lenses for controlling the radiation patterns of antennas are discussed, including several demonstrated examples of MM lenses that produce a single or multiple highly directive beams. Finally, the concept for a tunable anisotropic MM lens for reconfigurable azimuthal beam scanning in the horizontal plane is presented, including experimental verification of the proposed unit cell configuration.
|Title of host publication
|Broadband Metamaterials in Electromagnetics
|Subtitle of host publication
|Technology and Applications
|Pan Stanford Publishing Pte. Ltd.
|Number of pages
|Published - Jan 1 2017
All Science Journal Classification (ASJC) codes
- General Engineering
- General Materials Science