This presentation describes design and full wave analysis of terahertz integrated circuits using graphene plasmonic waveguides. First, we consider the material properties of graphene at optical and THz frequencies and later the propagation of electromagnetic waves through graphene plasmonic waveguide structures have been considered. Detailed modeling of graphene plasmonic parallel plate waveguide and it’s variants such as nano strip, suspended nano strip, coplanar and graphene backed coplanar waveguides have been carried out to determine phase constant, attenuation constant, characteristic impedance and propagation length of the guiding media. The modeling of physical discontinuities and their lumped element electrical equivalents have also been described so that it can be used in the design of integrated circuits at THz frequencies. Some design examples of graphene plasmonics based THz integrated circuits such as resonator, band pass filter, power splitter, coupler and antenna have also been provided.
5 years research experience in the field of graphene plasmonics, RF devices modeling and simulation, analysis and characterization.
Graphene THz devices design, micro-fabrication, graphene plasmonics based platforms for passive RF and THz integrated circuits.
RF devices modeling, simulations and analysis.
PhD, Electronics & Communication Engineering
Thesis title: Graphene based Plasmonic Integrated circuits for Terahertz Applications
Indian Institute of Technology (IIT) Roorkee, India 2018
M. Tech., Electronics & Communication Engineering
Thesis title: Photonic crystal tapers for effective coupling
Malviya National Institute of Technology (MNIT) Jaipur, India
Cumulative Performance Index (CPI): 9.35/10 2009
B.E., Electronics & Communication Engineering
University of Rajasthan, Jaipur, India 76.27% (Honors) 2006
Indian Institute of Technology (IIT) Roorkee, India
Utilized curve-fitting approaches and CST simulation techniques for graphene plasmonic waveguide to obtain it’s characteristics such as normalized propagation constant, characteristic impedance and propagation length. Full wave simulation software (CST-Microwave Studio) has been used in this study, which is used to analyze the characteristics of variants of graphene plasmonic parallel plate waveguide such as graphene plasmonic nanostrip waveguide, graphene plasmonic suspended nanostrip waveguide, graphene plasmonic coplanar waveguide, graphene plasmonic graphene backed coplanar waveguide. Also, the graphene plasmonic waveguide based discontinuities such as open-end, step and short discontinuities have been studied.
Design and analysis of graphene plasmonic waveguide based resonators and filters to obtain single-band and dual-band frequency response along with low-insertion loss and tunability.
Design and analysis of graphene plasmonic wavelength-division-demultiplexer (WDM), diplexer and directional coupler for THz communications.
Design and analysis of a graphene based patch antenna at THz frequencies.Master of Technology, Communication Ministry of Human Resource Development (MHRD), India July, 2007 to May, 2009
Studied photonic crystal band-gaps in development of taper structures required for efficient coupling between optical fibers and waveguides or vice-versa.
Design and analysis of photonic crystal tapers for lesser dispersion and effective coupling.
Fellowship granted by Ministry of Human Resource Development (MHRD), India, 2013-2018.
Fellowship granted by Ministry of Human Resource Development (MHRD), India, 2007-2009.
Plasmonic devices: Designing and simulation in CST Microwave studio. Surface chemistry/functionalization of graphene material. Worked in class 1000 clean room using spin coating, ultrasonication, photolithographic techniques.
Electronics: Electronic circuit designing, filters, antennas. Knowledge of PCB layout.
Computer and Programming skills: Platforms: MS Windows, Linux. Software Applications: MS Office, Excel, MATLAB, Origin, Visio, AutoCAD, electronic designing software ADS, HFSS, CST Microwave studio. Programming languages: C, C++.
Analytical and Communication Skills: Design and analysis of devices, data analysis and interpretation, generating written documentation, research reports, training students.
Joshi N. and Pathak N. P., “Modeling of graphene coplanar waveguide and its discontinuities for THz integrated circuit applications,” Plasmonics, pp 1-10, Nov, 2016.
Joshi N. and Pathak N. P., “Tunable wavelength demultiplexer using modified graphene plasmonic split ring resonators for terahertz communication,” Photonics and nanostructures-fundamentals and applications, vol. 28. pp. 1-5, Feb 2018.
Joshi N. and Janyani V., “Efficient coupling for chirped photonic crystal taper with photonic crystal waveguide”, Journal of Optics, India, Vol. 38, No. 4, pp. 216-231, June 2009.
Joshi, N., Pathak, N. P., “Graphene Backed Graphene Plasmonic Coplanar Waveguide (GB- GPCPW) for Terahertz Integrated Circuit Applications ,” Proceedings of Applied Electromagnetics Conference IEEE, Dec. 2015.
Joshi N. and Pathak N. P., “Concurrent dual-band tunable graphene based band-pass filter,” ICIIS,Roorkee, India, Dec., 2016.
Joshi N. and Pathak N. P., “Modeling and design of graphene based power splitter,” ISSS, Bangalore, India, July, 2017.
Joshi N. and Pathak N. P., “Compact ultra-wide-band graphene based tunable band-pass filter,” Second international conference on Advanced Functional Materials, Los Angeles, U.S.A. Aug. 4-6, 2017.
Janyani V., Joshi N., Pagaria J., and Pathak P., “Photonic Crystals for Novel Applications in Integrated-Optic Communication Systems and Devices”, ICECSD, Paris, France, June 2009.
Worked as Assistant Professor – Electronics & Communication Department, National Institute of Technology (NIT), Srinagar, Uttarakhand, from July 2011 to Dec 2012 (On Contract Basis).
Taken responsibility to establish Digital Communications, Analog and Digital Electronics Labs.
Guided electronic projects course and helped in designing electronic circuits like fire alarm, water alarm etc. Taken responsibility as coordinator for Central Counselling Board (CCB) for counselling of first year students of NIT, Uttarakhand. Subject Taught - Communication system, Digital Communication, Basic Electronics and Network analysis. Took additional responsibility of Girls
Hostel warden from July 2012 to Dec 2012.
Worked as Lecturer at AMITY University, Jaipur Campus from May 2009 to April 2010. Subject Taught - Digital Communication, Analog electronics and VHDL .
Worked as Lecturer at Sobhasaria Engineering College, Sikar, Rajasthan from March 2007 to June 2007, Subject Taught – CAD VLSI.
Member, Institute of Electrical and Electronics Engineers (IEEE)
Member, Microwave Theory and Techniques Society (MTTS)