Design and Development of Novel Nut-shaped SRR unit cell and analysis of DNG property

This paper presents design and development of a novel Nut-shaped Metamaterial Split Ring Resonator as a unit cell. Metamaterials with negative permittivity and permeability play a crucial role in improving the antenna performance. The unit cell comprises of two Split Ring Resonator with a thin transmission line connecting them. This structure measures a size 12 mm x 12 mm on the FR4 substrate of 16 mm x 16 mm x 1.6 mm. The shape of the unit cell developed in this work has been evolved using nature-inspired fractal geometries on a FR4 substrate. The simulation in the frequency range 2-4 GHz and the retrieval of negative medium properties have been carried out using HFSS 18.2 and MATLAB respectively. The fabrication and experimental verification have also been performed. Using the transmission〖 S〗_21 and reflection S_11 properties the double negative medium properties have been studied using both the Nicholson-Ross-Weir as well as the Transmission-Reflection methods. Comparison of simulation and experimental results of both the methods exhibit the existence of negative medium properties of the unit cell within the selected frequency range. The proposed unit cell exhibits the Effective medium ratio value of 8.16 and 7.45 at 3.06 GHz and 3.35 GHz. This type of DNG SRR unit cell is recommended for Electromagnetic Energy harvesting applications.