Dual Property of Mu-near-zero to Epsilon-near-zero Material

Abstract

In this paper, a mu-near-zero (MNZ) material is theoretically demonstrated to have a dual property of an epsilon-near-zero (ENZ) material, such as narrow channel tunneling and a zero transmitted angle. In order for an electromagnetic wave to transmit; through arbitrarily-shaped subwavelength narrow channel filled with an ENZ or MNZ material, both a proper boundary and a proper geometry of the narrow channel are required. These conditions turn out to have a duality relation between the ENZ and the MNZ materials. As an application of zero transmitted angle through a MNZ material, a X-band E-plane sectoral horn, which has improved directivity and which uses a MNZ material slab with a plasma frequency of 9.34 GHz, is designed. The results show that the directivity of the E-plane sectoral horn is increased by 2.59 dB when a MNZ material slab is inserted at the horn aperture.