Design and simulation of a novel compact unitcell for DNG metamaterials based on stepped-impedance resonator technique

This paper presents the design and simulation of a novel compact unitcell structure for Double Negative (DNG) metamaterials. The technique used in this unitcell is based on the concept of stepped-impedance resonators. Stepped-impedance resonators have many applications in the design of bandpass filters and duplexers, but have never been used for miniarurization of DNG unitcells. A simple model is used to describe the behavior of the stepped-impedance configuration. With this feature, a size reduction of 75% is achieved for the unitcell. This unitcell structure will be used for designing a compact planar DNG superstrate for gain enhancement of microstrip antennas.