Broaden the Bandwidth of Patch Antenna by Using Inhomogeneous Metamaterial Substrate

Abstract

Inhomogeneous substrate has proven to be an e-cient approach to broaden the bandwidth of the patch antenna. Because of its inhomogeneity, it is very di-cult to manufacture it by using ordinary materials. In this paper, we flrst optimize the inhomogeneity of the substrate with physical insight and then use nonresonant metamaterial elements to realize it. By tuning the geometrical parameter of the metamaterial element, the efiective constitutive parameters can be controlled; the permittivity and permeability are well designed to optimize the bandwidth of the antenna. As the working frequency is far from the resonant region of the element, it is expected to exhibit stable efiective constitutive parameters in a large frequency range. Our results have shown that the metamaterial substrate broadened the bandwidth of the antenna from 10.5% to 20.6% (i10dB).