Plasmonic structures which are strongly confine electromagnetic wavesat the metal-dielectric boundary investigated theoretically and experimentally, can be a possible solution of implementation of Nano photonic circuit’s problem. Frequency dependent dielectric function of double negative materials and gold has substantial effect on the precision of explanation of optical properties. In this research, we proposed plasmonic parallel plate waveguide of graphene placed between double negative materials (DNM) and filled with gold (Au). Dispersion relation that defined the propagation properties below and above the cut off frequency at THz region derived using Lorentz Drude model which helped to find the permittivity of gold and DNM. Existence of Surface Plasmon Polariton (SPPs) of graphene structure and its the TM modes discussed due to highly confinement, illustrated using cutoff height by Lorentz Drude model which were the most authentic methodologies used for analysis of different lossless and lossy medium in photonics. Propagation properties of graphene structure, investigated when operation frequency near and far away from cut off frequency. The complete analysis offered some strategies for improvement to the design of sub-wavelength optical devices.

Keywords: Terahertz frequency, Propagation constant, Double negative material, Graphene plates