In this manuscript, plasmonic nano patch antenna on the graphene material is designed and analyzed. The conductivity of the graphene material is modeled using Kubo conductivity formula and it is tuned using chemical potential of graphene. Further, analysis of Drude dispersive model for the graphene matrial exhibits negative real permittivity which is the required criterion for the plasmonic resonance. The designed graphene nano patch antenna provides a gain of 3.52 dB at 30 THz frequency which is suitable for terahertz communication. It is demonstrated that the graphene nano patch antenna resonates at multiple frequencies by varying the chemical potential and three resonating frequencies 30, 115, 176 THz with good characteristics are observed at 1.3 eV chemical potential. The gain of the graphene nano patch antenna is enhanced approximately three times by changing the shape of the patch from square to L-shape.

In this manuscript the plasmonic flower shaped silver nano dipole antenna is investigated on the silicon dioxide substrate for the optical wireless communication. The nano-circuit modeling of the proposed flower shaped nano dipole antenna is discussed which will enable the design of nano-photonic chips. The resonance tuning of the proposed flower shaped nano antenna is exhibited through end-to-end stacking of the flower cells over a petal of the nanostructure. The various possible structures were designed to tune the frequency in the range from 170 to 271 THz which covers 1550 nm window of the optical communication. The gap tuned flower shaped nano dipole antenna is designed by controlling the optical coupling of the waves in between two dipole arms of the nano-antenna. Further the detailed investigation on the performance of the flower shaped nano dipole antenna is executed through the design parameters such as gap of the nano dipole antenna feed G and radius of the flower cell R. The optimum nano-antenna characteristics which are suitable for the optical wireless communication are observed at the resonance frequencies such as 270, 284.5, 260.5, 226.5 and 209 THz with reflection coefficients −42.17, −42.42, −42.17, −45.20 and −50.33 dB respectively.

In this manuscript, a pentagon shaped plasmonic graphene nano patch antenna is designed and investigated on silicon dioxide, silicon nitride and zinc oxide substrates. The optical characteristics of the graphene such as conductivity and permittivity are analyzed at various values of chemical potential using Kubo conductivity model. The plasmonic resonance of the proposed nano-antenna is analyzed through the graphene chemical potential varied in the span from 0.0 eV to 2.0 eV. It is observed that the proposed pentagon shaped graphene nano patch antenna shows good plasmonic resonance characteristics at 29.8750 THz with the reflection coefficient of-27.4153 dB, 91.5650 THz with-27.5179 dB and 853.7350 THz with-40.3267 dB on silicon dioxide, zinc oxide and silicon nitride substrates respectively. These optimum characteristics are observed at the chemical potential values 2.00 eV and 0.50 eV for the proposed graphene nano patch antenna.

This article provides an overview of plasmonic nano-antennas for photonic applications. This paper delves into the theoretical analysis of nano/optical antennas, including optical antenna impedance, near and far field characteristics, and directivity. The materials used for manufacturing optical antennas are discussed in the context of terahertz communication. The comparative analysis of different types of fabrication techniques on the nanoscale is presented as a requirement for the implementation of nano-antennas. The testing mechanism of the nano-antenna using microscopy techniques is also presented. A detailed review of the different shapes of the nano-antennas that are used for applications in the field of photonics is discussed. According to this review article, graphene, gold, and silver are the most promising materials. It is also noticed that pen-dip and direct growth are fast and inexpensive techniques for nano-antenna fabrication.

In this paper, the performance analysis of the WDM (wavelength division multiplexing) system on the optical fiber transmission link is proposed. High data transmission is possible by implementing a WDM optical communication system using different modulation formats. Firstly, the WDM optical communication system is designed on an Optiwave simulation tool and distortion in the optical fiber by “eye pattern analysis” is analyzed. Secondly, the optical SNR of the proposed WDM optical communication system is studied. Further, the bit-error rate (BER) plot is studied and optimization techniques are applied to enhance the proposed system for long-haul communication. Furthermore, the BER plots are analyzed by varying the length of the fiber and applying different coding techniques like NRZ (non-return zero), RZ (return to zero), QAM (quadrature amplitude modulation) etc. using the Optiwave simulation tool. The results obtained in the Optiwave simulation tool are validated by theoretical implementation in the MATLAB tool.

The manuscript portrays the investigation of a quantum plasmonic gold torus nanodipole antenna on a zinc oxide dielectric substrate for optical near-field communication. Initially, the dispersive behavior of gold and zinc oxide materials at terahertz is demonstrated through Drude and Lorentz models to confirm the suitability of the material for the design of nano-antenna. The proposed torus nanodipole antenna is analyzed in detail using substrate, torus and feeding gap design parameters of the antenna to obtain the desired plasmon resonance characteristics for optical near-field communication. The minimal reflection of - 50.50 dB is observed at 71.3 THz with a directivity of 1.91 dBi using a single nanodipole element. The torus nanodipole antenna array is proposed to enhance the directivity and gain of the torus nanodipole antenna. The directivities of 9.425 dBi, 12.63 dBi and 14.63 dBi and the gain of 7.69 dBi, 10.77 dBi and 13.3 dBi are observed for the 2x2, 3x3 and 4x4 element nanodipole arrays, respectively. The circuit modeling for the torus nanostructure is proposed and validated using the finite integration technique.