Planar magneto-dielectric metasubstrate for miniaturization of a microstrip patch antenna

Abstract

A practically realizable planar-type magneto-dielectric metasubstrate to miniaturize a microstrip patch antenna is presented. The metasubstrate consists of two twisted metallic striplines, which provides inherently high effective permittivity (Îμ eff) in a low frequency region together with strong magnetic resonance presenting high effective permeability (μ eff) in a high frequency range. We suggest using the unusual properties of both high Îμ eff and μ eff of the proposed metasubstrate to reduce the overall antenna size, which has been proven to be effective in dropping an antenna resonant frequency to lower than a half of the original resonant frequency. Moreover, we have shown that a fictitious metasubstrate entirely composed of a homogeneous material filled with frequency-dependent Îμ eff and μ eff also provides very similar antenna characteristics that are obtained using the fabricated inhomogeneous metasubstrate consisting of the twisted striplines. Therefore, we could confirm that the proposed metasubstrate indeed works as an effective material with high Îμ eff and μ eff just as we intended. Predicted results have shown good agreement with experimental data, which proves the validity of our approach. © 2012 Wiley Periodicals, Inc.