Transmission-Line Approach to Zero-Index Materials for Invisible Cloaks

Abstract

A design method for two-dimensional (2-D) zero-index materials (ZIMs) is presented based on the transmission-line (TL) approach in order to realize invisible cloaks for hiding objects. A simple 2-D distributed TL model is proposed and the formula to calculate the dispersion characteristics is theoretically derived. It is shown from the calculated dispersion characteristics that a Dirac cone is always formed at the T -point without adjustments of the unit cell for the degeneration of propagation modes and ZIMs can be easily designed with the proposed model. In addition, a ZIM operating at 5 GHz is designed with the proposed model, and its cloaking operations and the validity of the design theory are demonstrated by circuit simulations.