Design and modeling of a novel double negative metamaterial for broadband applications

Geometric shapes (arithmetically know geometries) that are electrically conducting have been investigated and studied in the form of inclusions as unit cell resonators (UCR) on a dielectric host material. The basic idea behind the study, is to synthesize structures (not available in nature) with tailor made electromagnetic response (initially by software based simulation) over the desired frequency band of interest for strategic applications, such as antennas, connectors, transmission lines and passive components in the microwave and cellular frequency bands. In this paper, we report computer software (HFSS and CAD-FEKO-Silver) based design and analysis relating to synthesis of two different geometrical shapes (of which one is a know shape: S, while the other we have synthesized: Butterfly type orthogonal set) that exhibit negative permittivity and permeability (also called as DNG or metamaterial) over the frequency band of interest. The first synthesized (for purpose of comparison and confirmation of frequency response and accuracy of the software used) is a well know and reported rectangular complementary `S' (metallic inclusions) shaped structure, arranged in the form of a two dimensional lattice array (1 ? 1)<sup>*</sup>4-representing one single unit called UCR on a dielectric host material and ultimately loaded into a metallic rectangular wave guide for the purpose of investigation and study. This was then compared with our novel composite structure (butterfly shaped orthogonally placed) consisting of an array (1 ? 1)<sup>*</sup>1- unit cell of circular cavity type butterfly like UCRs. Many such array-structures of single unit cells are combined and embedded into the double positive normal dielectric materials (DPS). HFSS and CAD-FEKO software has been utilized to optimize the structure in the band of interest. Simulation results conclude that the performance of our novel DNG structure (butterfly shaped orthogonally placed) are superior compared to the conventional `S' shaped structure designed at the same spot frequency. The butterfly structure demonstrated a much wider frequency band of operation, and substantial reduction in size when designed at the same center frequency of operation.