DOCSLIB.ORG

Combinations of Low/High Permittivity And/Or Permeability Substrates for Highly Directive Planar Metamaterial Antennas

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Combinations of Low/High Permittivity And/Or Permeability Substrates for Highly Directive Planar Metamaterial Antennas Special Issue on Metamaterials EBG Combinations of low/high permittivity and/or permeability substrates for highly directive planar metamaterial antennas G. Lovat, P. Burghignoli, F. Capolino and D.R. Jackson Abstract: An investigation of planar metamaterial antennas consisting of grounded metamaterial substrates with low and/or high values of the electric permittivity and/or the magnetic permeability excited by dipole sources is presented. Their performances are characterised in terms of their capa- bility to radiate high levels of power density in the broadside direction and to produce narrow pencil beams pointing at broadside with high directivity. To achieve a high directivity, a pair of weakly attenuated cylindrical leaky waves is excited along the metamaterial substrate; sufficient conditions are established for the existence of such leaky waves in terms of the values of the substrate permit- tivity and permeability. Approximate closed-form expressions are derived for the phase and attenu- ation constants of the leaky waves. Numerical results are given in order to illustrate the radiative features of this class of antennas and to validate the theoretical analysis. 1 Introduction medium with parameters mr, 1r excited by a horizontal elec- tric or magnetic dipole placed inside the slab or on the Periodic structures made of metallic and/or dielectric ground plane, respectively. The goal is to design planar inclusions in a uniform host medium may be represented, antennas with a simple single-dipole feed featuring enhanced in suitable frequency ranges, as homogeneous artificial broadside radiation and/or very high directivity at broadside. materials (metamaterials) that show novel and interesting Metamaterials are not usually isotropic when practically electromagnetic features. One of these features is the implemented, but the general properties discussed in this creation of highly directive radiation beams from simple paper for the isotropic case, assumed for simplicity, have sources such as dipoles or slots placed inside such materials, also been found assuming specific anisotropic models. as was obtained in the pioneering work of Gupta [1], In this contribution, we focus on a comparison among Poilasne et al. [2] and Enoch et al. [3] For a detailed antennas based on different realisations of substrates with historical overview of such enhanced-directivity antennas, high/low values of permittivity and/or permeability. The we address the reader to the Introduction of Lovat et al. possibility of achieving high levels of radiated power [4]. The structures considered here consist of a grounded density at broadside is ascertained, in connection with the metamaterial layer that may have either high or low values of the constitutive parameters of the substrate and values of permittivity and/or permeability, excited by of the electric or magnetic type of the source. Conditions either an electric or a magnetic dipole source. Such struc- for achieving the excitation of a pair of TEz and TMz tures are different from those where a cavity is created leaky modes (where z is the direction orthogonal to the under a partially reflective surface that is formed by high- air–slab interface) with small and equal values of the permittivity dielectrics [5–7], metallic FSS layers [8, 9] phase and attenuation constants are then derived, which is or other periodic dielectric structures [10, 11]. Although a requirement for the radiation of a highly directive pencil different in structure, the metamaterial antennas considered beam pointing at broadside with a circular cross-section in this work are similar in terms of the mechanism of [12]. The conclusions given in this paper provide guidelines radiation: in fact, all the antennas in [1–11] radiate a for a more comprehensive investigation assuming a more narrow beam because the feed excites slowly attenuating realistic homogeneous anisotropic model, or even the still leaky waves, as demonstrated in the work of Lovat et al. further realistic case of a metamaterial made of actual per- [4] and Jackson and Oliner [6]. iodic inclusions. Their importance rely also on the fact that The theory behind a grounded slab made of such metama- no other studies have been carried out so far on this topic, terials is revisited here, assuming a homogeneous isotropic and that the example seen in the literature represents just one of the possible choices (a low-permittivity metamater- ial) that can be adopted in order to realise a planar radiator # The Institution of Engineering and Technology 2007 with enhanced directivity or broadside radiation. doi:10.1049/iet-map:20050353 For convenience of the reader, the terminology adopted Paper first received 15th December 2005 and in revised form 20th July 2006 throughout the paper for describing the various considered G. Lovat and P. Burghignoli are with the Electronic Engineering Department, ‘La Sapienza’ University of Rome, Via Eudossiana 18, Roma 00184, Italy metamaterial media is reported here. F. Capolino is with the Information Engineering Department, University of Siena, Via Roma 56, Siena 53100, Italy MNZ – mu near zero, that is, jmrj1; D.R. Jackson is with the Department of Electrical and Computer Engineering, ENZ – epsilon near zero, that is, j1rj1; University of Houston, Houston, TX 77204-4005, USA MENZ – mu and epsilon near zero, that is, jmrj1, and E-mail: [email protected] j1rj1; IET Microw. Antennas Propag., 2007, 1, (1), pp. 177–183 177 Authorized licensed use limited to: Univ of Calif Irvine. Downloaded on April 4, 2009 at 15:36 from IEEE Xplore. Restrictions apply. MVL – mu very large, that is, jmrj1; as the ratio EP,J ¼ PJ(0)/PJ,0(0) between the broadside EVL – epsilon very large, that is,pj1rj1; power density radiated in the presence of the grounded Low-impedance material – hr ¼ (mr/1r) 1; slab PJ(0) and that radiated in free space PJ,0(0): the latter p 2 2 High-impedance material – phr ¼ (mr/1r) 1; is equal to PJ,0(0) ¼ k0h0/(32p )W/steradian [13],so Low-index material – nr ¼ p(mr1r) 1; that in this case High-index material – n ¼ (m 1 ) 1. r r r 2 EP;J ¼ 4hr ð3Þ 2 Maximisation of broadside radiation In contrast, for a magnetic dipole (whose broadside power 2 density radiated in free space is equal to PM,0(0) ¼ k0/ Let us consider a grounded slab as in Fig. 1, with constitu- 2 (32p h0)W/steradian), (1b) yields tive parameters mr, 1r, and thickness h, excited by a y-directed horizontal electric or magnetic dipole source k2 P ð0Þ¼ 0 ð4Þ placed at z ¼ hs or on the ground plane, respectively. The M 8p2h electric far field radiated by the electric dipole source at 0 broadside can be found by means of a simple application that is independent of hr. Hence a fixed enhancement factor of the reciprocity theorem [5]. This is done by letting a EP,M ¼ PM(0)/PM,0(0) ¼ 4 is obtained, which is the same y-polarised incident plane wave, having an amplitude of as that due to the ground plane alone, and therefore no the electric field equal to 2jk0h0 exp(2jk0r)/(4pr) at the power enhancement at broadside is obtained from the meta- origin, impinge on the structure from broadside, and then material. It can be concluded that, for high-impedance slabs, calculating the reaction between the dipole source and the electric sources must be employed in order to enhance electric field inside the structure due to the incident plane broadside radiation. wave. A similar analysis holds for the magnetic dipole source, using an x-polarised incident plane wave and Case 2: Materials with low intrinsic impedance. taking the reaction between the dipole source and the Conversely, considering metamaterial slabs with very low resulting magnetic field inside the structure. The resulting values of intrinsic impedance, that is, with hr 1, it can broadside angular power density (W/steradian) at broadside easily be seen from (1) that, for both electric and magnetic (u ¼ 0) is found to be sources, the broadside power density is maximised when h ¼ (2n 2 1)l1/4(n ¼ 1, 2, ...). For an electric source, k2h h2 sin2ðk h Þ by letting n ¼ 1, the optimum source location is h ¼ h, P ð0Þ¼ 0 0 r 1 s ð1aÞ s J 2 2 2 2 for which (1a) gives the broadside power density as 8p cos ðk1hÞþhr sin ðk1hÞ 2 2 k0 1 k0 h0 P ð0Þ¼ ð1bÞ PJð0Þ¼ ð5Þ M 2 2 2 2 8p2 8p h0 cos ðk1hÞþhr sin ðk1hÞ which is independent of hr. In contrast, for a magnetic for a unit-amplitude electric dipole moment and for a source, (1b) gives the broadside power density as unit-amplitudep magnetic dipolep moment, respectively,p where k ¼ v (m 1 ), h ¼ (m /1 ), k ¼ k (m 1 ) and 2 p 0 0 0 0 0 0 1 0 r r k0 h ¼ (m /1 ). The power density at broadside is investi- P ð0Þ¼ ð6Þ r r r M 8p2h h2 gated below assuming two cases: high- and low-impedance 0 r materials, since a large broadside power density requires which can be made very large by decreasing the normalised one of these two cases. slab impedance hr either by using a MNZ and/or a EVL material. The relevant power enhancement factor is Case 1: Materials with high intrinsic impedance. 4 Considering metamaterial slabs with very high values of ¼ ð Þ EP;M 2 7 normalised intrinsic impedance, that is, with hr 1, it hr can easily be seen from (1) that, for both electric and mag- netic sources, the broadside power density is maximised It can be concluded that, for low-impedance slabs, magnetic p sources must be employed in order to enhance broadside when h ¼ nl1/2 (where l1 ¼ l0 (mr1r) and n ¼ 1, 2, ...).
Load more

Recommended publications
  • Chapter 1 Metamaterials and the Mathematical Science
    CHAPTER 1 METAMATERIALS AND THE MATHEMATICAL SCIENCE OF INVISIBILITY André Diatta, Sébastien Guenneau, André Nicolet, Fréderic Zolla Institut Fresnel (UMR CNRS 6133). Aix-Marseille Université 13397 Marseille cedex 20, France E-mails: [email protected];[email protected]; [email protected]; [email protected] Abstract. In this chapter, we review some recent developments in the field of photonics: cloaking, whereby an object becomes invisible to an observer, and mirages, whereby an object looks like another one (say, of a different shape). Such optical illusions are made possible thanks to the advent of metamaterials, which are new kinds of composites designed using the concept of transformational optics. Theoretical concepts introduced here are illustrated by finite element computations. 1 2 A. Diatta, S. Guenneau, A. Nicolet, F. Zolla 1. Introduction In the past six years, there has been a growing interest in electromagnetic metamaterials1 , which are composites structured on a subwavelength scale modeled using homogenization theories2. Metamaterials have important practical applications as they enable a markedly enhanced control of electromagnetic waves through coordinate transformations which bring anisotropic and heterogeneous3 material parameters into their governing equations, except in the ray diffraction limit whereby material parameters remain isotropic4 . Transformation3 and conformal4 optics, as they are now known, open an unprecedented avenue towards the design of such metamaterials, with the paradigms of invisibility cloaks. In this review chapter, after a brief introduction to cloaking (section 2), we would like to present a comprehensive mathematical model of metamaterials introducing some basic knowledge of differential calculus. The touchstone of our presentation is that Maxwell’s equations, the governing equations for electromagnetic waves, retain their form under coordinate changes.
    [Show full text]
  • Plasmonic and Metamaterial Structures As Electromagnetic Absorbers
    Plasmonic and Metamaterial Structures as Electromagnetic Absorbers Yanxia Cui 1,2, Yingran He1, Yi Jin1, Fei Ding1, Liu Yang1, Yuqian Ye3, Shoumin Zhong1, Yinyue Lin2, Sailing He1,* 1 State Key Laboratory of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Zhejiang University, Hangzhou 310058, China 2 Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan, 030024, China 3 Department of Physics, Hangzhou Normal University, Hangzhou 310012, China Corresponding author: e-mail [email protected] Abstract: Electromagnetic absorbers have drawn increasing attention in many areas. A series of plasmonic and metamaterial structures can work as efficient narrow band absorbers due to the excitation of plasmonic or photonic resonances, providing a great potential for applications in designing selective thermal emitters, bio-sensing, etc. In other applications such as solar energy harvesting and photonic detection, the bandwidth of light absorbers is required to be quite broad. Under such a background, a variety of mechanisms of broadband/multiband absorption have been proposed, such as mixing multiple resonances together, exciting phase resonances, slowing down light by anisotropic metamaterials, employing high loss materials and so on. 1. Introduction physical phenomena associated with planar or localized SPPs [13,14]. Electromagnetic (EM) wave absorbers are devices in Metamaterials are artificial assemblies of structured which the incident radiation at the operating wavelengths elements of subwavelength size (i.e., much smaller than can be efficiently absorbed, and then transformed into the wavelength of the incident waves) [15]. They are often ohmic heat or other forms of energy.
    [Show full text]
  • Dielectric Permittivity Model for Polymer–Filler Composite Materials by the Example of Ni- and Graphite-Filled Composites for High-Frequency Absorbing Coatings
    coatings Article Dielectric Permittivity Model for Polymer–Filler Composite Materials by the Example of Ni- and Graphite-Filled Composites for High-Frequency Absorbing Coatings Artem Prokopchuk 1,*, Ivan Zozulia 1,*, Yurii Didenko 2 , Dmytro Tatarchuk 2 , Henning Heuer 1,3 and Yuriy Poplavko 2 1 Institute of Electronic Packaging Technology, Technische Universität Dresden, 01069 Dresden, Germany; [email protected] 2 Department of Microelectronics, National Technical University of Ukraine, 03056 Kiev, Ukraine; [email protected] (Y.D.); [email protected] (D.T.); [email protected] (Y.P.) 3 Department of Systems for Testing and Analysis, Fraunhofer Institute for Ceramic Technologies and Systems IKTS, 01109 Dresden, Germany * Correspondence: [email protected] (A.P.); [email protected] (I.Z.); Tel.: +49-3514-633-6426 (A.P. & I.Z.) Abstract: The suppression of unnecessary radio-electronic noise and the protection of electronic devices from electromagnetic interference by the use of pliable highly microwave radiation absorbing composite materials based on polymers or rubbers filled with conductive and magnetic fillers have been proposed. Since the working frequency bands of electronic devices and systems are rapidly expanding up to the millimeter wave range, the capabilities of absorbing and shielding composites should be evaluated for increasing operating frequency. The point is that the absorption capacity of conductive and magnetic fillers essentially decreases as the frequency increases. Therefore, this Citation: Prokopchuk, A.; Zozulia, I.; paper is devoted to the absorbing capabilities of composites filled with high-loss dielectric fillers, in Didenko, Y.; Tatarchuk, D.; Heuer, H.; which absorption significantly increases as frequency rises, and it is possible to achieve the maximum Poplavko, Y.
    [Show full text]
  • Metamaterial Waveguides and Antennas
    12 Metamaterial Waveguides and Antennas Alexey A. Basharin, Nikolay P. Balabukha, Vladimir N. Semenenko and Nikolay L. Menshikh Institute for Theoretical and Applied Electromagnetics RAS Russia 1. Introduction In 1967, Veselago (1967) predicted the realizability of materials with negative refractive index. Thirty years later, metamaterials were created by Smith et al. (2000), Lagarkov et al. (2003) and a new line in the development of the electromagnetics of continuous media started. Recently, a large number of studies related to the investigation of electrophysical properties of metamaterials and wave refraction in metamaterials as well as and development of devices on the basis of metamaterials appeared Pendry (2000), Lagarkov and Kissel (2004). Nefedov and Tretyakov (2003) analyze features of electromagnetic waves propagating in a waveguide consisting of two layers with positive and negative constitutive parameters, respectively. In review by Caloz and Itoh (2006), the problems of radiation from structures with metamaterials are analyzed. In particular, the authors of this study have demonstrated the realizability of a scanning antenna consisting of a metamaterial placed on a metal substrate and radiating in two different directions. If the refractive index of the metamaterial is negative, the antenna radiates in an angular sector ranging from –90 ° to 0°; if the refractive index is positive, the antenna radiates in an angular sector ranging from 0° to 90° . Grbic and Elefttheriades (2002) for the first time have shown the backward radiation of CPW- based NRI metamaterials. A. Alu et al.(2007), leaky modes of a tubular waveguide made of a metamaterial whose relative permittivity is close to zero are analyzed.
    [Show full text]
  • Metamaterials and the Landau–Lifshitz Permeability Argument: Large Permittivity Begets High-Frequency Magnetism
    Metamaterials and the Landau–Lifshitz permeability argument: Large permittivity begets high-frequency magnetism Roberto Merlin1 Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 Edited by Federico Capasso, Harvard University, Cambridge, MA, and approved December 4, 2008 (received for review August 26, 2008) Homogeneous composites, or metamaterials, made of dielectric or resonators, have led to a large body of literature devoted to metallic particles are known to show magnetic properties that con- metamaterials magnetism covering the range from microwave to tradict arguments by Landau and Lifshitz [Landau LD, Lifshitz EM optical frequencies (12–16). (1960) Electrodynamics of Continuous Media (Pergamon, Oxford, UK), Although the magnetic behavior of metamaterials undoubt- p 251], indicating that the magnetization and, thus, the permeability, edly conforms to Maxwell’s equations, the reason why artificial loses its meaning at relatively low frequencies. Here, we show that systems do better than nature is not well understood. Claims of these arguments do not apply to composites made of substances with ͌ ͌ strong magnetic activity are seemingly at odds with the fact that, Im ␧S ϾϾ ␭/ഞ or Re ␧S ϳ ␭/ഞ (␧S and ഞ are the complex permittivity ␭ ϾϾ ഞ other than magnetically ordered substances, magnetism in na- and the characteristic length of the particles, and is the ture is a rather weak phenomenon at ambient temperature.* vacuum wavelength). Our general analysis is supported by studies Moreover, high-frequency magnetism ostensibly contradicts of split rings, one of the most common constituents of electro- well-known arguments by Landau and Lifshitz that the magne- magnetic metamaterials, and spherical inclusions.
    [Show full text]
  • Dynamic Simulation of a Metamaterial Beam Consisting of Tunable Shape Memory Material Absorbers
    vibration Article Dynamic Simulation of a Metamaterial Beam Consisting of Tunable Shape Memory Material Absorbers Hua-Liang Hu, Ji-Wei Peng and Chun-Ying Lee * Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 10608, Taiwan; [email protected] (H.-L.H.); [email protected] (J.-W.P.) * Correspondence: [email protected]; Tel.: +886-2-8773-1614 Received: 21 May 2018; Accepted: 13 July 2018; Published: 18 July 2018 Abstract: Metamaterials are materials with an artificially tailored internal structure and unusual physical and mechanical properties such as a negative refraction coefficient, negative mass inertia, and negative modulus of elasticity, etc. Due to their unique characteristics, metamaterials possess great potential in engineering applications. This study aims to develop new acoustic metamaterials for applications in semi-active vibration isolation. For the proposed state-of-the-art structural configurations in metamaterials, the geometry and mass distribution of the crafted internal structure is employed to induce the local resonance inside the material. Therefore, a stopband in the dispersion curve can be created because of the energy gap. For conventional metamaterials, the stopband is fixed and unable to be adjusted in real-time once the design is completed. Although the metamaterial with distributed resonance characteristics has been proposed in the literature to extend its working stopband, the efficacy is usually compromised. In order to increase its adaptability to time-varying disturbance, several semi-active metamaterials have been proposed. In this study, the incorporation of a tunable shape memory alloy (SMA) into the configuration of metamaterial is proposed. The repeated resonance unit consisting of SMA beams is designed and its theoretical formulation for determining the dynamic characteristics is established.
    [Show full text]
  • Measurement of Dielectric Material Properties Application Note
    with examples examples with solutions testing practical to show written properties. dielectric to the s-parameters converting for methods shows Italso analyzer. a network using materials of properties dielectric the measure to methods the describes note The application | | | | Products: Note Application Properties Material of Dielectric Measurement R&S R&S R&S R&S ZNB ZNB ZVT ZVA ZNC ZNC Another application note will be will note application Another <Application Note> Kuek Chee Yaw 04.2012- RAC0607-0019_1_4E Table of Contents Table of Contents 1 Overview ................................................................................. 3 2 Measurement Methods .......................................................... 3 Transmission/Reflection Line method ....................................................... 5 Open ended coaxial probe method ............................................................ 7 Free space method ....................................................................................... 8 Resonant method ......................................................................................... 9 3 Measurement Procedure ..................................................... 11 4 Conversion Methods ............................................................ 11 Nicholson-Ross-Weir (NRW) .....................................................................12 NIST Iterative...............................................................................................13 New non-iterative .......................................................................................14
    [Show full text]
  • Physics 115 Lightning Gauss's Law Electrical Potential Energy Electric
    Physics 115 General Physics II Session 18 Lightning Gauss’s Law Electrical potential energy Electric potential V • R. J. Wilkes • Email: [email protected] • Home page: http://courses.washington.edu/phy115a/ 5/1/14 1 Lecture Schedule (up to exam 2) Today 5/1/14 Physics 115 2 Example: Electron Moving in a Perpendicular Electric Field ...similar to prob. 19-101 in textbook 6 • Electron has v0 = 1.00x10 m/s i • Enters uniform electric field E = 2000 N/C (down) (a) Compare the electric and gravitational forces on the electron. (b) By how much is the electron deflected after travelling 1.0 cm in the x direction? y x F eE e = 1 2 Δy = ayt , ay = Fnet / m = (eE ↑+mg ↓) / m ≈ eE / m Fg mg 2 −19 ! $2 (1.60×10 C)(2000 N/C) 1 ! eE $ 2 Δx eE Δx = −31 Δy = # &t , v >> v → t ≈ → Δy = # & (9.11×10 kg)(9.8 N/kg) x y 2" m % vx 2m" vx % 13 = 3.6×10 2 (1.60×10−19 C)(2000 N/C)! (0.01 m) $ = −31 # 6 & (Math typos corrected) 2(9.11×10 kg) "(1.0×10 m/s)% 5/1/14 Physics 115 = 0.018 m =1.8 cm (upward) 3 Big Static Charges: About Lightning • Lightning = huge electric discharge • Clouds get charged through friction – Clouds rub against mountains – Raindrops/ice particles carry charge • Discharge may carry 100,000 amperes – What’s an ampere ? Definition soon… • 1 kilometer long arc means 3 billion volts! – What’s a volt ? Definition soon… – High voltage breaks down air’s resistance – What’s resistance? Definition soon..
    [Show full text]
  • Realization of a Thermal Cloak–Concentrator Using a Metamaterial
    www.nature.com/scientificreports OPEN Realization of a thermal cloak– concentrator using a metamaterial transformer Received: 2 November 2017 Ding-Peng Liu, Po-Jung Chen & Hsin-Haou Huang Accepted: 23 January 2018 By combining rotating squares with auxetic properties, we developed a metamaterial transformer Published: xx xx xxxx capable of realizing metamaterials with tunable functionalities. We investigated the use of a metamaterial transformer-based thermal cloak–concentrator that can change from a cloak to a concentrator when the device confguration is transformed. We established that the proposed dual- functional metamaterial can either thermally protect a region (cloak) or focus heat fux in a small region (concentrator). The dual functionality was verifed by fnite element simulations and validated by experiments with a specimen composed of copper, epoxy, and rotating squares. This work provides an efective and efcient method for controlling the gradient of heat, in addition to providing a reference for other thermal metamaterials to possess such controllable functionalities by adapting the concept of a metamaterial transformer. Te concept of controlling energy can be traced back to the pioneering proposals by Pendry1 and Leonhardt2, whose approaches to cloaking provided means of manipulating electromagnetic waves. Following their research, eforts have been devoted to modeling and designing coordinate transformation-based metamaterials, also known as thermal metamaterials3–5, in the feld of thermodynamics. Owing to the unconventional nature of thermal metamaterials, various applications such as the thermal cloak6–14, thermal concentrator15–17, thermal inverter18–20 and thermal illusion21–24 have been proposed. Recently, thermoelectric components25 have ofered a method for actively controlling heat fux.
    [Show full text]
  • High Dielectric Permittivity Materials in the Development of Resonators Suitable for Metamaterial and Passive Filter Devices at Microwave Frequencies
    ADVERTIMENT. Lʼaccés als continguts dʼaquesta tesi queda condicionat a lʼacceptació de les condicions dʼús establertes per la següent llicència Creative Commons: http://cat.creativecommons.org/?page_id=184 ADVERTENCIA. El acceso a los contenidos de esta tesis queda condicionado a la aceptación de las condiciones de uso establecidas por la siguiente licencia Creative Commons: http://es.creativecommons.org/blog/licencias/ WARNING. The access to the contents of this doctoral thesis it is limited to the acceptance of the use conditions set by the following Creative Commons license: https://creativecommons.org/licenses/?lang=en High dielectric permittivity materials in the development of resonators suitable for metamaterial and passive filter devices at microwave frequencies Ph.D. Thesis written by Bahareh Moradi Under the supervision of Dr. Juan Jose Garcia Garcia Bellaterra (Cerdanyola del Vallès), February 2016 Abstract Metamaterials (MTMs) represent an exciting emerging research area that promises to bring about important technological and scientific advancement in various areas such as telecommunication, radar, microelectronic, and medical imaging. The amount of research on this MTMs area has grown extremely quickly in this time. MTM structure are able to sustain strong sub-wavelength electromagnetic resonance and thus potentially applicable for component miniaturization. Miniaturization, optimization of device performance through elimination of spurious frequencies, and possibility to control filter bandwidth over wide margins are challenges of present and future communication devices. This thesis is focused on the study of both interesting subject (MTMs and miniaturization) which is new miniaturization strategies for MTMs component. Since, the dielectric resonators (DR) are new type of MTMs distinguished by small dissipative losses as well as convenient conjugation with external structures; they are suitable choice for development process.
    [Show full text]
  • Metamaterials for Electromagnetic and Thermal Waves
    Metamaterials for electromagnetic and thermal waves 1 1,2 1,3 1 Erin Donnelly , Antoine Durant , Célia Lacoste , Luigi La Spada 1School of Engineering and the Built Environment, Edinburgh Napier University, Edinburgh, United Kingdom 2IUT1, Université Grenoble Alpes, Grenoble, France 3INP-ENSEEIHT, University of Toulouse, Toulouse, France [email protected] Abstract— In the last decade, electromagnetic is of great interest in any industrial applications. Moreover, metamaterials, thanks to their exotic properties and the unsolved issues are still present: significant presence of possibility to control electromagnetic waves at will, become losses, narrow bandwidth, material properties difficult to crucial building blocks to develop new and advanced technologies in several practical applications. Even though achieve, complexity in both design and manufacturing. until now the metamaterial concept has been mostly associated Therefore, in this paper, we model, design and fabricate a with electromagnetism and optics; the same concepts can be multi-functional metamaterial able to control amplitude and also applied to other wave phenomena, such as phase of both electromagnetic and thermal wave. thermodynamics. For this reason, here the aim is to realize a The paper is organized as follows: (i) in the modeling multi-functional metamaterial able to control and manipulate section, by using field theory, we evaluate the metamaterial simultaneously both electromagnetic and thermal waves. fundamental parameters: electric permittivity ε and thermal
    [Show full text]
  • Realization of an All-Dielectric Zero-Index Optical Metamaterial
    Realization of an all-dielectric zero-index optical metamaterial Parikshit Moitra1†, Yuanmu Yang1†, Zachary Anderson2, Ivan I. Kravchenko3, Dayrl P. Briggs3, Jason Valentine4* 1Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37212, USA 2School for Science and Math at Vanderbilt, Nashville, TN 37232, USA 3Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 4Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA †these authors contributed equally to this work *email: [email protected] Metamaterials offer unprecedented flexibility for manipulating the optical properties of matter, including the ability to access negative index1–4, ultra-high index5 and chiral optical properties6–8. Recently, metamaterials with near-zero refractive index have drawn much attention9–13. Light inside such materials experiences no spatial phase change and extremely large phase velocity, properties that can be applied for realizing directional emission14–16, tunneling waveguides17, large area single mode devices18, and electromagnetic cloaks19. However, at optical frequencies previously demonstrated zero- or negative- refractive index metamaterials require the use of metallic inclusions, leading to large ohmic loss, a serious impediment to device applications20,21. Here, we experimentally demonstrate an impedance matched zero-index metamaterial at optical frequencies based on purely dielectric constituents. Formed from stacked silicon rod unit cells, the metamaterial possesses a nearly isotropic low-index response leading to angular selectivity of transmission and directive emission from quantum dots placed within the material. Over the past several years, most work aimed at achieving zero-index has been focused on epsilon-near-zero metamaterials (ENZs) which can be realized using diluted metals or metal waveguides operating below cut-off.
    [Show full text]