Electrically Small Planar Antennas Based on Metamaterial

Abstract

Planar antennas are suitable for broadband solution applications due to their low profile, wide bandwidth, ease of manufacturing, and simple geometry. They include antennas with planar radiators such as microstrip antennas, suspended plate antennas, coplanar waveguide (CPW) antennas, planar monopole antennas, and planar inverted-L and inverted-F antennas (PILAs and PIFAs). Applications have covered cellular phone systems and wireless local area networks (WLANs), wireless personal area networks (WPANs), and Worldwide Interoperability for Microwave Access (WiMAX). Planar electrically small antennas (ESAs) are a new research topic, and many researchers are interested in working on its subtopics. This research work has been extensively studied over the decades for different microwave applications (Christou and Polycarpou, IEEE Trans Electromagn Compat 59(2), 2017; Manteghi, IEEE Trans Antennas Propag 64(4), 2016). Due to its compact dimension, an ESA always exhibits a high impedance mismatch, high quality factor, and low cross-polarization especially for a planar antenna; also, it provides good overall efficiency (OE) and a narrow fractional bandwidth (FBW). For an ESA, there is always an essential lower bound on the quality factor concerning the antenna’s physical size and operating wavelength or frequency range.