پديد آورنده :
اميري نائيني، مريم السادات
عنوان :
طراحي و تحليل ساختارهاي متناوب حلقوي گرافني و پياده سازي يك جاذب
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
مخابرات - ميدان و موج
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر
صفحه شمار :
دوازده، ۷۹ص.: مصور، جدول، نمودار
استاد راهنما :
محسن مداح علي
استاد مشاور :
احمد بخت افروز
توصيفگر ها :
گرافن , آرايه هاي متناوب , جاذب ها , مدار معادل فشرده
استاد داور :
داور( اختياري): ابوالقاسم زيدآبادي نژاد، ذاكر حسين فيروزه
تاريخ ورود اطلاعات :
1396/09/25
رشته تحصيلي :
برق و كامپيوتر
دانشكده :
مهندسي برق و كامپيوتر
چكيده انگليسي :
Design and Analysis of Graphene Ring Periodic Structures and Implementation of an Absorber Maryam Sadat Amiri Naeini maryamossadat amiri@ec iut ac ir November 26 2017 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mohsen Maddahali maddahali@cc iut ac ir Abstract Recently Graphene has attracted researchers attention because of its exclusive thermal mechanical and electromag netical properties Investigating the plasmons behavior in Graphene shows its potential to be a good substitute for noblemetals in plasmonics specially due to its controllable conductivity which provides more freedom in designing procedure forengineers As a result Graphene periodic arrays are very useful structures in frequency selective surfaces Faraday rotators polarizers filters and so on The absorbers which are very beneficial structures have been also affected by these new find ings Here we purpose to design and analyze Graphene terahertz absorbers using a lumped element equivalent circuit model The idea of presenting equivalent nano circuits for plasmonic nano particles was first proposed in 2005 A nano particlebehaves as an inductor or capacitor based on the sign of the real part of its permittivity to be negative or positive respectively The imaginary part of the permittivity causes the losses and acts as a resistor Thus a nano particle with a complex per mittivity could be modeled as an RC or RL lumped circuit The permittivity of materials depends on frequency in somecases and we can approximate their behavior as an RLC circuit in which the incuctive or capacitive attitude dominatesdepending on the situation Exactly the same idea can be used for a Graphene patch This fascinating property providesus with the ability to modify the conductivity of different parts of a Graphene layer by adjusting the chemical potential inorder to design arrays with desired characteristics In this thesis an analytical circuit model is introduced for an array ofGraphene rings To achieve the goal the surface current density function is calculated on an isolated ring using quasi staticapproximation Then the results are developed to a 2 D periodic array of Graphene rings by means of the first order pertur bation theory The surface boundary condition for electromagnetic waves together with the Rayleigh expansion is used tocalculate the reflection coefficients and the closed form of the equations for the equivalent circuit elements afterwards Theresults are verified by comparing them with the ones derived from COMSOL software full wave analysis and the accuracyof the method is proved Finally we have benefited from the circuit model to design a wide band absorber Introducinga closed form for the equivalent lumped circuit of a Graphene periodic array as a function of its structural and geometricparameters helps us to design or improve them for more desirable results more facilely This will be helpful in designingabsorbers as well Absorbers are very useful structures in sensing imaging photodetection and cloaking applications Key Words Graphene Periodic Arrays Absorbers Lumped Element Equivalent Circuit
استاد راهنما :
محسن مداح علي
استاد مشاور :
احمد بخت افروز
استاد داور :
داور( اختياري): ابوالقاسم زيدآبادي نژاد، ذاكر حسين فيروزه
