EPJ Applied Metamaterials
Volume 1, 2014
|Number of page(s)||9|
|Published online||08 July 2014|
Metamaterials: The early years in the USA
Department of Electrical and Computer Engineering, The University of Arizona, Tucson, AZ, USA
Accepted: 6 May 2014
Published online: 8 July 2014
Metamaterials are artificial materials formed by embedding highly subwavelength inclusions in a host medium, which yield homogenized permittivity and permeability values. By design they offer the promise of exotic physics responses not generally available with naturally occurring materials, as well as the ability to tailor their properties to specific applications. The initial years of discovery emphasized confirming many of their exotic properties and exploring their actual potential for science and engineering applications. These seed efforts have born the sweet fruit enjoyed by the current generation of metamaterials scientists and engineers. This review will emphasize the initial investigative forays in the USA that supported and encouraged the development of the metamaterials era and the subsequent recognition that they do have significant advantages for practical applications.
Key words: Artificial dielectrics / Double negative materials / Epsilon negative materials / Metamaterials / Mu negative materials / Plasmonics
© R.W. Ziolkowski, Published by EDP Sciences, 2014
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Artificial materials have had an enormous impact historically. Well-known examples include the beautiful 13th century stained glass windows in Notre-Dame Cathedral and La Sainte-Chapelle in Paris, their colors originating from plasmonic effects arising from various metallic inclusions in the glasses. In the late part of the 19th century, Jagadis Chunder Bose published his work on the rotation of the plane of polarization by man-made twisted structures, which were indeed artificial chiral structures by today’s definition . Karl Ferdinand Lindman studied artificial chiral media formed by a collection of randomly-oriented small wire helices in 1914 . In the 1950’s and 1960’s, the work of Kock , for example, explored artificial dielectric light-weight microwave antenna lenses for satellite applications. To understand the Mercury and Gemini spacecraft re-entry communication blackout periods, the “bed of nails” wire grid medium was introduced in the early 1960’s to simulate the propagation of waves in plasmas . Artificial electric and magnetic materials were at the heart of the stealth aircraft programs in the 1980’s and beyond. Similarly, the resurrected interest in artificial chiral materials in the 1980’s and 1990’s (see, e.g., ) arose from their potential applications as microwave radar absorbers.
Ziolkowski at the University of Arizona (UAz) was contacted in July 1999 by Prof. Rodger M. Walser, University of Texas at Austin (UT Austin), about an invitation-only DARPA Workshop to be held in November, 1999. These are the kind of events in which the participants have the chance to influence a call-for-proposals (CFP). I quite naturally agreed to participate. I was invited because of our artificial atom/molecule investigations and their applications to radar absorbing materials (RAMs) and smart skins (surfaces that could change their characteristics in response to an interrogating signal) [6–11]. These efforts had already led to our studies on how one might use these artificial material models to realize absorbing boundary conditions (ABCs) in finite difference time domain (FDTD) simulations [12–15]. They were “physical” realizations of the (at the time) revolutionary perfect matched layer (PML) ABCs .
Walser released the general invitation in September 1999 stating: “DARPA is interested in gathering information concerning the area of artificially constructed materials, or Meta-materials, which possess qualitatively new responses that do not occur in nature”. This was the first time I had seen the phrase “Meta-materials”. As he did in a later paper , Walser explained at the workshop that the choice of name came from the desire to achieve material performances “beyond” the limitations of conventional composites. The workshop program consisted of an Applications Section  and a Materials Modeling and Processing Section . Drs. Stu Wolf and Bill Coblenz of DARPA/DSO (Defense Sciences Office) and Dr. Valerie Browning, who was at NRL and coming on board at DARPA at the time, ran the workshop. The presentations were an interesting mixture of results on electromagnetic bandgap structures and complex media.
The workshop led to an eventual DARPA MURI (Multi-University Research Initiative) CFP (MURI Call for Proposals: Topic 33, Electromagnetic Metamaterials) in 2001 whose stated objective was: “To model, synthesize, characterize, and develop new synthetic metamaterials which exhibit properties that can be used in a wide range of applications spanning the electromagnetic spectrum”. The winning proposal was entitled “Scalable and Reconfigurable Electromagnetic Metamaterials and Devices”; the team consisted of several well-known talents . Dr. Browning later described her new program on Metamaterials at the DARPA Tech 2002 meeting by saying that : “A metamaterial is an engineered composite that exhibits superior properties not observed in nature or in the constituent materials”. I believe that it is an interesting historical observation that the term “metamaterials” was truly introduced into the community because of a DARPA funding opportunity.
Much of the effort in the early metamaterials period in the USA, like elsewhere in the world, emphasized investigating and proving the exotic physics properties of metamaterials. The first negative index and then negative refraction investigations and experiments were performed at UC San Diego (UCSD) [22–25]. At the same time, the seminal applications paper on the “perfect lens” concept appeared . Full-wave vector simulations and a detailed analysis of double negative (DNG) metamaterials confirmed their negative index properties . One very important precursor to these experiments was the IEEE MTT special issue on electromagnetic periodic structures . Several notable papers were included that emphasized artificial magnetism. The split ring resonator (SRR) was introduced by an Imperial College-GEC-Marconi team . Structured surfaces that act as artificial magnetic conductors (AMCs) were introduced by UCLA teams: the mushroom surface type  and the frequency selective surface (FSS) type [31, 32]. Given the timing on all of these papers in relation to the DARPA workshop, they clearly had a significant impact on the outcome of the above mentioned DARPA MURI CFP.
The excitement about metamaterials at the time became contagious. Since the original artificial magnetic experiments were in the microwave regime and given the potential of a perfect lens, the physics/optics community quickly tried to push the concepts up to optical frequencies. A special issue of Optics Express with Pendry as its Guest Editor summarizes some of the thrusts at that time . These included advances in simulating the propagation in and scattering from DNG media at UCSD, ISU, and UAz [34–36]; advances in superlens technologies at UCLA ; refinements of the negative refraction experiments at Boeing ; reports of yet more exotic phenomena by Penn State University , MIT , and Purdue University (Purdue) ; and illustrating DNG phenomena can be obtained from electromagnetic band-gap (EBG) structures by a MIT-Imperial College team .
A metasurface at telecom frequencies based on SRRs was reported by the collaborative team from Iowa State University, Karlsruhe Institute of Technology, and FORTH in Crete . This Soukoulis-Wegener-led collaboration has led to numerous contributions to the successful development of optical metamaterials [44, 45]. However, this team pointed out earlier that because of kinetic inductance effects, SRR-based unit cells would not reach visible frequencies  and suggested an alternative approach . A University of New Mexico and Columbia University team proposed yet a different architecture . The first demonstration of metamaterials in the visible, which employed a fishnet structure, was reported in  by the ISU-Karlsruhe team. Shalaev reviewed the state-of-the-art in  and his Purdue team officially reached visible frequencies with their fishnet structure in . The Nanophotonics Group at Purdue with their outstanding fabrication capabilities in the Birck Nanotechnology Center has continued to push DNG effects further into the visible regime. Shalaev and Boardman organized another OSA focus issue on metamaterials published in 2006 .
On the West coast, Zhang moved from UCLA to UC Berkeley in 2004 and established the NSF Nano-Scale Science and Engineering Center (NSEC). They have demonstrated and verified many of the hypenlens and superlens concepts [53–55]. They made one of the first examples of a superlattice optical metamaterial . They have demonstrated plasmon lasers at visible frequencies . In the South, Scalora at the Redstone Arsenal in Alabama and his collaborators have considered numerous aspects of DNG media and subwavelength focusing .
On the East coast, Engheta at the University of Pennsylvania (UPenn) had been involved with complex media for many years. He developed a variety of RAMs based on bi-anisotropic materials . It has been demonstrated by many groups now that the Ω-medium he introduced  can be designed to exhibit DNG properties . He also has introduced and developed the paradigm of Metatronics [62–64] and with Alù, whose is now at UT Austin, considered how basic antenna concepts can used successfully to design and analyze nano-antennas and their properties [65, 66].
An important aspect to note about the first wave of discoveries in the early days was the controversy surrounding negative refraction and perfect lensing [67–73]. While such discussions can be healthy, they tend to be distracting, impacting both progress and effort levels. Nevertheless, Dr. Browning recognized the importance of the debate. Because one of the issues was the impact the size of the negative index wedge may have had on the original experiments, she asked the Boeing Phantom Works (now Boeing Research and Development) team  to construct a larger version which was tested successfully by several independent laboratories and was highlighted in . She also held a workshop at DARPA in 2003  to which both critics and proponents alike were invited to discuss metamaterial issues such as negative refraction. A second DARPA MURI CFP on metamaterials later occurred in 2004.
While the concept of artificial magnetism at optical frequencies captured the attention of the optics community, it was, as noted above, not new to the engineering electromagnetics community. Other aspects of metamaterials, however, were of immediate interest to the microwave community. The original negative index experiments exhibited performance characteristics that were not acceptable for practical microwave applications. However, Ziolkowski demonstrated in  that low-loss DNG bulk metamaterials could be designed to be matched to free-space. Engheta ascertained how (extremely) electrically small resonant cavities could be realized with matching DNG metamaterials with double positive (DPS) materials . Ziolkowski employed this concept, for instance, to achieve highly subwavelength, ultra-thin laser designs . It was also recognized that planar metamaterials were possible by employing transmission line concepts. In particular, two-dimensional transmission line metamaterials were realized simultaneously at the University of Toronto  and at UCLA . Both groups also recognized that the metamaterial approach provided the first means for scanning a leaky wave antenna (an array formed by a periodic arrangement of DNG unit elements) from the backfire, through the broadside, and to the endfire directions [82, 83]. Furthermore, it was reported by different UCLA groups [31, 84] and by a team from the European Space Agency and the University of Navarra , that electromagnetic band-gap structures could impact the performance of antennas and arrays of them.
To get the word out about these exciting developments, Engheta and Ziolkowski organized special sessions associated with metamaterials at the 2002 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting, San Antonio, Texas, June, 2002. They solicited contributors there and issued a call for papers as the guest editors for the first IEEE special issue on metamaterials. This issue, which was sponsored by the IEEE Antennas and Propagation (AP) Society, was published in October 2003 . A second special issue was published in April 2005 with Itoh and Oliner as the Guest Editors  and was sponsored by the IEEE Microwave Theory and Techniques (MTT) society.
The AP-S issue included several topics reported by USA groups who continued to contribute into the second half of the first decade of metamaterials. The first paper by the UAz group on metamaterial-based electrically small antennas appeared in it . Several years of their metamaterial-inspired antenna efforts were summarized in . They also developed a bulk metamaterial AMC (with no ground plane) to realize a low-profile antenna system . The first paper by the UPenn group on cloaking (transparency or scattering cancellation) and tunneling also appeared in it . They have continued their contributions to the development of cloaking approaches [92–94]. An HRL team introduced a tunable version of the Sievenpiper mushroom surface to achieve beam steering . Other antenna contributions included the UCLA realization of low profile antennas using EBG ground planes  and the investigations of lowering the mutual coupling between antenna elements in arrays . Their continued efforts have been compiled in the book . Another low profile antenna system introduced by an Arizona State University-Etenna Corp. team took advantage of the high impedance mushroom surface as an AMC . A University of Michigan team led by Volakis used topological optimization to design a metamaterial to improve the bandwidth of a patch antenna . After his move to Ohio State University, Volakis has used a variety of metamaterial constructs to enhance various antenna performance characteristics [101–103]. Another University of Michigan team led by Sarabandi also has investigated a variety of metamaterials and their antenna applications [104–107]. A NIST-Boulder and UC Boulder team reported the proper characterization of meta-surfaces [108, 109]. They have worked with several collaborators to continue to refine their approach for a variety of meta-film constructs [110–112].
Like Eleftheriades’ U Toronto group, the Itoh-Caloz UCLA team used transmission line metamaterials to achieve numerous microwave engineering devices and antenna systems since their inception. For instance, the U Toronto group reported a compact phase shifter in . In the MTT special issue, the UCLA team, which became the UCLA-Montreal University team in 2004, reported a compact diplexer . A summary of several of their antennas was given in . A summary of various metamaterial-based antennas was given by UCLA in .
Yet another IEEE special issue, highlighting both the microwave and optical regimes, was guest edited recently by Eleftheriades and Engheta . Several more summary papers of the metamaterial efforts reported by many USA and international groups can be found in it.
The second DARPA MURI on Metamaterials started in 2005  and was led by the Boeing Phantom Works team. While several of its outcomes were mentioned topically above, it also led to some of the electrically smallest single negative (SNG) and DNG unit cells produced to date. The experiments confirmed the designs; a low loss DNG bulk metamaterial was realized at UHF frequencies [119, 120].
Important classes of metamaterials that I would like to highlight in closing are those involving active elements and those which exhibit extreme properties. Several have garnered enormous attention both technically and generally in recent years.
Active molecules were reported in [9–11], for instance, for smart skins; but the idea of using active inclusions to develop broad bandwidth metamaterials was emphasized by Tretyakov at Aalto University in . Active metamaterials (i.e., metamaterials formed by introducing gain devices such as transistors or operational amplifiers into their inclusions and, hence, unit cells) for RF frequencies have been designed by a team at Duke . These principles have been used by them to realize lossless magnetic  and non-reciprocal  microwave metamaterials. Non-Foster elements to achieve dispersionless, wide bandwidth and superluminal effects in metamaterials have been studied by Hrabar’s team at the University of Zagreb [125–127]. Superluminal waveguides based on non-Foster circuits have been reported by Sievenpiper’s UCSD group . Nonlinear metamaterials, emphasizing the SRR type of elements, have been investigated extensively by Kivshar’s University of Canberra team [129–131]. The SRR-type unit cells augmented with non-Foster elements also have been reported for other metamaterial-inspired structures by teams at Northeastern University  and Rome Tré . By introducing non-Foster circuit elements into their metamaterial-inspired antenna designs, the UAz team has overcome several basic physics bounds on small radiators to realize electrically small, efficient, broad impedance bandwidth and high directivity systems [134–138]. The U Toronto group has also reported non-Foster augmentations of antennas  and has considered alternative designs for non-Foster circuit implementations . Because of the presence of active elements in all these metamaterial-inspired structures, there is a need to understand their stability in practice. While the various individual groups have provided stability analyses of their components, more general considerations have been reported by a team from the University of Carlos III de Madrid and the University of Zagreb  and a Queen Mary University of London team . Several successful uses for active metamaterials in the THz regime have been reported by the Boston College (BC)-Boston University (BU) team .
While many of these lower frequency applications have added performance enhancements, the concept of introducing gain into metamaterial structures to overcome the losses associated with their constituents has become critical in the optical domain. Whether it is optical metamaterials, core-shell nanoparticles or plasmonic-based devices, the losses associated with their metal constituents is unforgiving. Gain is a possible enabling technology to significantly improve the possible applications of metamaterial structures in the visible. For example, the Purdue team originally recognized gain was a path to a high figure of merit in ; they demonstrated a lossless visible metamaterial in this manner in . The UAz team has considered over coming losses in the visible with gain in metallic-dielectric core-shell nanoparticles. While they demonstrated the possibility of core-shell nano-lasers  and active epsilon-near-zero (ENZ) meta-surfaces , collaborations between the UAz, Technical University of Denmark (DTU) and Shanghai Jiao Tong University (SJTU) have extended these designs to demonstrate super-resonant scattering [146, 148], gain-enhanced metamaterial-inspired nano-antennas , and active quantum jammers . It should be added that loss compensation with gain is also intimately connected to the coupling between metamaterial and the gain medium. Without sufficient coupling, no loss compensation can happen, nor can the transmitted signal be amplified. Therefore, it is of vital importance to understand the mechanism of the coupling between the metamaterial and the gain medium. The issue was tackled in the papers from the ISU-Karlsruhe [151, 152] and Imperial College London  teams.
One metamaterial topic that has garnered enormous attention since 2006 is cloaking. The Duke-Imperial College team first reported their cloaking success in , based on their transformation optics (TO) approach . Whether you are of the Klingon-Star Trek or Harry Potter ages, this work was exciting and has greatly stimulated efforts in the electromagnetics, acoustics and elastic communities worldwide. Another related concept at the other extreme is the perfect absorber reported by a BC-Duke collaboration , which has initiated a flurry of papers considering numerous designs and potential applications.
One aspect of the TO or the UPenn scattering cancellation/transparency approaches to cloaking is the need to have metamaterials whose material properties are extreme, i.e., either close to zero or close to infinity. The high impedance surfaces realizing AMCs (i.e., they act as ENZ or permittivity-to-infinity metamaterials) or their duals are further examples. The UPenn team has employed the ENZ concepts effectively to achieve a variety of super-coupling effects [157, 158].
An interesting related issue with the transmission line metamaterials is the fact that in their balanced condition, the propagation constant β = 0, which means the index of refraction is zero. Consequently, the wavelength and phase speed are infinite at the point between which the transmission line is left-handed or right-handed . This behavior led to the concept of infinite wavelength resonances and devices . On the other hand, the UAz team recognized that since one can tune the permittivity or permeability to any value one would like and since matching is important for any source or scattering problem, one could consider making a metamaterial with both its permittivity and permeability being zero, i.e., a matched zero index metamaterial . It was recognized that with a zero-index medium, one could achieve high directivity sources or could tailor phase fronts to any desired shape. The UPenn team illustrated how one could perform similar operations with ENZ metamaterials .
Indeed, exploiting extreme properties to control wave-matter interactions continues to be an active area of investigation. A number of very interesting linear and nonlinear properties are being discovered and reported. Fascinating applications has been uncovered and a variety of them are being pursued currently.
The early years of metamaterials took the science and engineering communities by storm. I have tried in this paper to provide some additional perspectives and details about the work done in the USA during this time period. Many more of the early technical accomplishments were captured in the first three metamaterial reference books [163–165]. While the early years emphasized understanding the basics, the following years began a transition into potential and actual applications.
The interest and level of activity of the first decade of metamaterials has been sustained and has even increased going into the second one. However, the metamaterials community is now faced with the need to demonstrate the usefulness of its work to society by succeeding in the development of useful current and future applications. Maybe we should call them meta-applications – those beyond what we could have only done with the old ideas and materials of the previous century. It will be a great pleasure to watch more of the discoveries and developments in metamaterials and meta-applications unfold in the pages of this new journal, EPJ AM.
First, I would like to thank Prof. Yang Hao, EIC of the EPJ AM, for his very kind invitation to me to share with you some metamaterial history in the USA for this inaugural issue. Second, I must apologize to everyone who I did not mention or whose work I did not mention in this review. There are many of you, and the community has produced so very many interesting works. I must simply beg all of you for your forgiveness. Third, I would like to thank the reviewers for their careful reading of this paper; your comments helped improve it. Finally, to the next generations of metamaterial scientists and engineers, there is much yet for you to do. When someone tells you it is meta-impossible, press on, enjoy the journey of discovery, and prove them wrong.
- J.C. Bose, On the rotation of plane of polarisation of electric waves by a twisted structure, Proc. Royal Society 63 (1898) 146–152. [CrossRef] [Google Scholar]
- I.V. Lindell, A.H. Sihvola, J. Kurkijarvi, Karl F. Lindman: The last Hertzian, and a harbinger of electromagnetic chirality, IEEE Antennas Propag. Mag. 34, 3 (1992) 24–30. [CrossRef] [Google Scholar]
- W.E. Kock, Metallic delay lenses, Bell Syst. Tech. J. 27 (1948) 58–82. [CrossRef] [Google Scholar]
- W. Rotman, Plasma simulation by artificial dielectrics and parallel-plate media, IRE Trans. Antennas Propag. 10 (1962) 82–95. [CrossRef] [Google Scholar]
- N. Engheta (Guest Ed.), Wave interactions with chiral and complex media, Special Issue of the J. Electromagn. Waves Appl. 6, 5/6 (1992). [Google Scholar]
- R.W. Ziolkowski, F. Auzanneau, Artificial molecule realization of a magnetic wall, J. Appl. Phys. 82, 7 (1997) 3192–3194. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, F. Auzanneau, Passive artificial molecule realizations of dielectric materials, J. Appl. Phys. 82, 7 (1997) 3195–3198. [CrossRef] [Google Scholar]
- F. Auzanneau, R.W. Ziolkowski, Theoretical study of synthetic bianisotropic materials, J. Electromagn. Waves Appl. 12, 3 (1998) 353–370. [CrossRef] [Google Scholar]
- F. Auzanneau, R.W. Ziolkowski, Microwave signal rectification using artificial composite materials composed of diode loaded, electrically small dipole antennas, IEEE Trans. Microwave Theor. Tech. 46, 11 (1998) 1628–1637. [CrossRef] [Google Scholar]
- F. Auzanneau, R.W. Ziolkowski, Explicit matrix formulation for the analysis of synthetic linearly and nonlinearly loaded materials in FDTD, J. Electromagn. Waves Appl. 13 (1999) 1509–1510; Progress in Electromagnetics Research, PIER 24, 139–161, 1999. [CrossRef] [Google Scholar]
- F. Auzanneau, R.W. Ziolkowski, Artificial composite materials consisting of linearly and nonlinearly loaded electrically small antennas: operational amplifier based circuits with applications to smart skins, IEEE Trans. Antennas Propag. 47 8 (1999) 1330–1339. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, The design of Maxwellian absorbers for numerical boundary conditions and for practical applications using engineered artificial materials, IEEE Antennas Propag. 45, 4 (1997) 656–671. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, Time derivative Lorentz-materials and their utilization as electromagnetic absorbers, Phys. Rev. E 55, 6 (1997) 7696–7703. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, Time derivative Lorentz-material based absorbing boundary conditions, IEEE Antennas Propag. 45, 10 (1997) 1530–1535. [CrossRef] [Google Scholar]
- D.C. Wittwer, R.W. Ziolkowski, Two time-derivative Lorentz material (2TDLM) formulation of a Maxwellian absorbing layer matched to a lossy media, IEEE Trans. Antennas Propag. 48, 2 (2000) 192–199. [CrossRef] [Google Scholar]
- J.-P. Berenger, A perfectly matched layer for the absorption of electromagnetic waves, J. Comput. Phys. 114 (1994) 185–200. [NASA ADS] [CrossRef] [MathSciNet] [Google Scholar]
- R.M. Walser, Electromagnetic metamaterials, in Proc. SPIE 4467 Complex Mediums II: Beyond Linear Isotropic Dielectrics, 1, San Diego, CA, 2001, pp. 1–15. [Google Scholar]
- Speakers included: Roger Walser (UT Austin), RM Dickinson (JPL), Eli Yablonovich (UCLA), Ananth Dodabalapur (Lucent), George Whitesides (Harvard), Nick Alexopolus (UC Irvine), Will McKenzie (Atlantic Aerospace), Rick Ziolkowski (U Arizona) and Akhlesh Lakhtakia (Penn State U). [Google Scholar]
- Speakers included: Ken Suslick (U Illinois), Bruce Dunn (Penn State U), Ray Baughman (Allied Signals), Chris Murray (IBM), Mike Cima (MIT), Steve Chou (Princeton), and John Halloran (U Michigan). [Google Scholar]
- Team Members included: Xiang Zhang (PI, UC Berkeley), Eli Yablonovitch and Tasuo Itoh (UCLA), Sheldon Schultz and David R. Smith (UCSD), Gang Chen and John Joannopoulus (MIT) and John Pendry (Imperial College); http://xlab.me.berkeley.edu/MURI/muri.html [Google Scholar]
- http://archive.darpa.mil/DARPATech2002/presentations/dso_pdf/speeches/BROWNING.pdf [Google Scholar]
- D.R. Smith, W.J. Padilla, D.C. Vier, S.C. Nemat-Nasser, S. Schultz, Composite medium with simultaneously negative permeability and permittivity, Phys. Rev. Lett. 84, 18 (2000) 4184–4187. [CrossRef] [PubMed] [Google Scholar]
- D.R. Smith, N. Kroll, Negative refractive index in left-handed materials, Phys. Rev. Lett. 85, 14 (2000) 2933–2936. [CrossRef] [PubMed] [Google Scholar]
- R.A. Shelby, D.R. Smith, S.C. Nemat-Nasser, S. Schultz, Microwave transmission through a two-dimensional, isotropic, left-handed metamaterial, Appl. Phys. Lett. 78, 4 (2001) 489–491. [CrossRef] [Google Scholar]
- A. Shelby, D.R. Smith, S. Schultz, Experimental verification of a negative index of refraction, Science 292, 5514 (2001) 77–79. [CrossRef] [PubMed] [Google Scholar]
- J.B. Pendry, Negative refraction makes a perfect lens, Phys. Rev. Lett. 85, 18 (2000) 3966–3969. [CrossRef] [PubMed] [Google Scholar]
- R.W. Ziolkowski, E. Heyman, Wave propagation in media having negative permittivity and permeability, Phys. Rev. E 64 (2001) 056625. [CrossRef] [Google Scholar]
- A. Scherer, T. Doll, E. Yablonovich, H. Everitt, A. Higgins (Guest Eds.), Focus Issue: Artificial and Metallodielectric Electromagnetic Crystals, IEEE Trans. Microwave Theor. Tech., 47, 11 (1999) [CrossRef] [Google Scholar]
- J.B. Pendry, A.J. Holden, D.J. Robbins, W.J. Stewart, Magnetism from conductors and enhanced nonlinear phenomena, IEEE Trans. Microwave Theor. Tech., 47, 11 (1999) 2075–2081. [CrossRef] [Google Scholar]
- D. Sievenpiper, L. Zhang, R. Broas, N.G. Alexopolous, E. Yablonovitch, High-impedance electromagnetic surfaces with a forbidden frequency band, IEEE Trans. Microwave Theor. Tech. 47, 11 (1999) 2059–2074. [CrossRef] [Google Scholar]
- R. Coccioli, F.-R. Yang, K.-P. Ma, T. Itoh, Aperture-coupled patch antenna on UC-PBG substrate, IEEE Trans. Microwave Theor. Tech. 47, 11 (1999) 2123–2130. [CrossRef] [Google Scholar]
- F.-R. Yang, K.-P. Ma, Y. Qian, T. Itoh, A novel TEM waveguide using uniplanar compact photonic-bandgap (UC-PBG) structure, IEEE Trans. Microwave Theor. Tech. 47, 11 (1999) 2092–2098. [CrossRef] [Google Scholar]
- J. Pendry (Guest Eds.), OSA Focus Issue: Negative Refraction and Metamaterials, Opt. Express 11, 7 (2003) [Google Scholar]
- P. Kolinko, D. Smith, Numerical study of electromagnetic waves interacting with negative index materials, Opt. Express 11, 7 (2003) 640–648. [CrossRef] [Google Scholar]
- P. Markos, C. Soukoulis, Transmission properties and effective electromagnetic parameters of double negative metamaterials, Opt. Express 11, 7 (2003) 649–661. [CrossRef] [PubMed] [Google Scholar]
- R.W. Ziolkowski, Pulsed and CW Gaussian beam interactions with double negative metamaterial slabs, Opt. Express 11, 7 (2003) 662–681. [CrossRef] [Google Scholar]
- N. Fang, Z. Liu, T.-J. Yen, X. Zhang, Regenerating evanescent waves from a silver superlens, Opt. Express 11, 7 (2003) 649–661. [CrossRef] [PubMed] [Google Scholar]
- R. Greegor, C. Parazzoli, K. Li, B. Koltenbah, M. Tanielian, Experimental determination and numerical simulation of the properties of negative index of refraction materials, Opt. Express 11, 7 (2003) 688–695. [CrossRef] [Google Scholar]
- A. Lakhtakia, Handedness reversal of circular Bragg phenomenon due to negative real permittivity and permeability, Opt. Express 11, 7 (2003) 716–722. [CrossRef] [Google Scholar]
- J. Lu, T. Grzegorczyk, Y. Zhang, J. Pacheco Jr, B.-I. Wu, J. Kong, M. Chen, Čerenkov radiation in materials with negative permittivity and permeability, Opt. Express 11, 7 (2003) 723–734. [CrossRef] [Google Scholar]
- V. Podolskiy, A. Sarychev, V. Shalaev, Plasmon modes and negative refraction in metal nanowire composites, Opt. Express 11, 7 (2003) 735–745. [CrossRef] [Google Scholar]
- C. Luo, S.G. Johnson, J.D. Joannopoulos, J.B. Pendry, Negative refraction without negative index in metallic photonic crystals, Opt. Express 11, 7 (2003) 746–754. [CrossRef] [PubMed] [Google Scholar]
- S. Linden, C. Enkrich, M. Wegener, J. Zhou, Th. Koschny, C.M. Soukoulis, Magnetic response of metamaterials at 100 terahertz, Science 306, 5700 (2004) 1351–1353. [CrossRef] [PubMed] [Google Scholar]
- C.M. Soukoulis, S. Linden, M. Wegener, Negative refractive index at optical wavelengths, Science 315, 5808 (2007) 47–49. [CrossRef] [PubMed] [Google Scholar]
- C.M. Soukoulis, M. Wegener, Past achievements and future challenges in the development of three-dimensional photonic metamaterials, Nature Photon. 5 (2011) 523–530. [Google Scholar]
- S. Linden, C. Enkrich, G. Dolling, M.W. Klein, J. Zhou, Th. Koschny, C.M. Soukoulis, S. Burger, F. Schmidt, M. Wegener, Photonic metamaterials: magnetism at optical frequencies, IEEE J. Sel. Top. Quantum Electron. 12, 6 (2006) 1097–1105. [CrossRef] [Google Scholar]
- J. Zhou, L. Zhang, G. Tuttle, Th. Koschny, C.M. Soukoulis, Negative index materials using simple short wire pairs, Phys. Rev. B 73 (2006) 041101(R). [CrossRef] [Google Scholar]
- S. Zhang, W. Fan, K.J. Malloy, S.R.J. Brueck, N.C. Panoiu, R.M. Osgood, Demonstration of metal-dielectric negative-index metamaterials with improved performance at optical frequencies, J. Opt. Soc. Am. B 23, 3 (2006) 434–438. [CrossRef] [Google Scholar]
- G. Dolling, M. Wegener, C.M. Soukoulis, S. Linden, Negative-index metamaterial at 780 nm wavelength, Opt. Lett. 32, 1 (2007) 53–55. [CrossRef] [Google Scholar]
- V.M. Shalaev, Optical negative-index metamaterials, Nature Photon. 1 (2007) 41–48. [CrossRef] [Google Scholar]
- U.K. Chettiar, A.V. Kildishev, H.-K. Yuan, W. Cai, S. Xiao, V.P. Drachev, V.M. Shalaev, Dual-band negative index metamaterial: double negative at 813 nm and single negative at 772 nm, Opt. Lett. 32, 12 (2007) 1671–1673. [CrossRef] [Google Scholar]
- V.M. Shalaev, A. Boardman, Focus issue on Metamaterials, J. Opt. Soc. Am. B 23, 3 (2006)386–387. [CrossRef] [Google Scholar]
- N. Fang, H. Lee, C. Sun, X. Zhang, Sub-diffraction-limited optical imaging with a silver superlens, Science 308 (2005) 534–537. [CrossRef] [PubMed] [Google Scholar]
- X. Zhang, Z. Liu, Superlenses to overcome the diffraction limit, Nature Mater. 7 (2008) 435–441. [CrossRef] [PubMed] [Google Scholar]
- J. Rho, Z. Ye, Y. Xiong, X. Yin, Z. Liu, H. Choi, G. Bartal, X. Zhang, Spherical hyperlens for two-dimensional sub-diffractional imaging at visible frequencies, Nature Comms. 1 (2010) 143. [CrossRef] [Google Scholar]
- J. Valentine, S. Zhang, T. Zentgraf, E. Ulin-Avila, D.A. Genov, G. Bartal, X. Zhang, Three-dimensional optical metamaterial with a negative refractive index, Nature 455 (2008) 376–379. [CrossRef] [PubMed] [Google Scholar]
- R.F. Oulton, V.J. Sorger, T. Zentgraf, R.-M. Ma, C. Gladden, L. Dai, G. Bartal, X. Zhang, Plasmon lasers at deep subwavelength scale, Nature 461 (2009) 629–632. [CrossRef] [PubMed] [Google Scholar]
- M. Scalora, G. D’Aguanno, N. Mattiucci, M.J. Bloemer, D. de Ceglia, M. Centini, A. Mandatori, C. Sibilia, N. Akozbek, M.G. Cappeddu, M. Fowler, J.W. Haus, Negative refraction and sub-wavelength focusing in the visible range using transparent metallo-dielectric stacks, Opt. Express 15, 2 (2007) 508–523. [CrossRef] [Google Scholar]
- D.L. Jaggard, N. Engheta, ChirosorbTM as an invisible medium, Electron. Lett. 25, 3 (1989) 173–174. [CrossRef] [Google Scholar]
- M.M.I. Saadoun, N. Engheta, A reciprocal phase shifter using novel pseudochiral or Ω medium, Microw. Opt. Technol. Lett. 5, 4 (1992) 184–188. [CrossRef] [Google Scholar]
- L.-X. Ran, J.T. Huang-Fu, H. Chen, X.-M. Zhang, K.S. Chen, T.M. Grzegorczyk, J.A. Kong, Experimental study on several left-handed metamaterials, Progress Electromagn. Res. 51 (2005) 249–279. [CrossRef] [Google Scholar]
- N. Engheta, A. Salandrino, A. Alù, Circuit elements at optical frequencies: nanoinductors, nanocapacitors, and nanoresistors, Phys. Rev. Lett. 95, 9 (2005) 095504. [CrossRef] [Google Scholar]
- N. Engheta, Circuits with light at nanoscales: Optical nanocircuits inspired by metamaterials, Science 317, 5845 (2007) 1698–1702. [CrossRef] [PubMed] [Google Scholar]
- N. Engheta, From RF circuits to optical nanocircuits, IEEE Microw. Mag. 13, 4 (2012) 100–113. [CrossRef] [Google Scholar]
- A. Alù, N. Engheta, Tuning the scattering response of optical nanoantennas with nanocircuit loads, Nature Photon. 2 (2008) 307–310. [CrossRef] [Google Scholar]
- A. Alù, N. Engheta, Input impedance, nanocircuit loading, and radiation tuning of optical nanoantennas, Phys. Rev. Lett. 101 (2008) 043901. [CrossRef] [Google Scholar]
- J.M. Williams, Some problems with negative refraction, Phys. Rev. Lett. 87, 24 (2001) 249703. [CrossRef] [Google Scholar]
- G.W. ‘t Hooft, Comment on “Negative refraction makes a perfect lens”, Phys. Rev. Lett. 87, 24 (2001) 249701. [CrossRef] [PubMed] [Google Scholar]
- D. Maystre, S. Enoch, Perfect lenses made with left-handed materials: Alice’s mirror? J. Opt. Soc. Am. A 21, 1 (2004) 122–131. [CrossRef] [Google Scholar]
- N. Garcia, M. Nieto-Vesperinas, Left-handed materials do not make a perfect lens, Phys. Rev. Lett. 88, 20 (2002) 207403. [CrossRef] [PubMed] [Google Scholar]
- N. Garcia, M. Nieto-Vesperinas, Is there an experimental verification of a negative index of refraction yet? Opt. Lett. 27, 11 (2002) 885–887. [CrossRef] [Google Scholar]
- P.M. Valanju, R.M. Walser, A.P. Valanju, Wave refraction in negative-index media: always positive and very inhomogeneous, Phys. Rev. Lett. 88 (2002) 187401. [CrossRef] [PubMed] [Google Scholar]
- J.B. Pendry, D.R. Smith, Comment on “Wave Refraction in Negative-Index Media: Always Positive and Very Inhomogeneous”, Phys. Rev. Lett. 90 (2003) 029703. [CrossRef] [Google Scholar]
- C.G. Parazzoli, R.B. Greegor, K. Li, B.E.C. Koltenbah, M. Tanielian, Experimental verification and simulation of negative index of refraction using Snell’s law, Phys. Rev. Lett. 90, 10 (2003) 107401. [CrossRef] [PubMed] [Google Scholar]
- J.B. Pendry, D.R. Smith, Reversing light with negative refraction, Physics Today 57, 6 (2004) 37–43; cover photo: “The Boeing cube”: a structure designed for negative refractive index in the GHz range. [CrossRef] [Google Scholar]
- V. Browning. DARPA Workshop on Negative Index MetaMaterials, May 2003. Participants included: V. Veselago (Moscow Institute of Physics and Technology, Russia), David Smith (UCSD), C. Parazzoli (Boeing), T. Schaefer (Mayo Clinic), J. Kong (MIT), Douglas Smith (NRL), S. Schultz (UCSD), R. Ziolkowski (UA), N. Engheta (U Penn), S. Sridhar (Northeastern), C. Caloz and T. Itoh (UCLA), A. Lakhtakia (PSU), C. Krowne (NRL), V. Agranovich (Institute of Spectroscopy, Russia), and D. Sievenpiper (HRL). [Google Scholar]
- R.W. Ziolkowski, Design, fabrication, and testing of double negative metamaterials, IEEE Trans. Antennas Propag. 51, 7 (2003) 1516–1529. [CrossRef] [Google Scholar]
- N. Engheta, An idea for thin subwavelength cavity resonators using metamaterials with negative permittivity and permeability, IEEE Antennas Wireless Propag. 1, 1 (2002) 10–13. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, Ultra-thin metamaterial-based laser cavities, J. Opt. Soc. Am. B 23 (2006) 451–460. [CrossRef] [Google Scholar]
- A. Grbic, G.V. Eleftheriades, Negative refraction, growing evanescent waves, and sub-diffraction imaging in loaded transmission-line metamaterials, IEEE Microwave Theor. Tech. 51, 12 (2003) 2297–2305. [CrossRef] [Google Scholar]
- A. Lai, T. Itoh, C. Caloz, Composite right/left-handed transmission line metamaterials, IEEE Microw. Mag. 5, 3 (2004) 34–50. [CrossRef] [Google Scholar]
- A. Grbic, G.V. Eleftheriades, Experimental verification of backward-wave radiation from a negative refractive index metamaterial, J. Appl. Phys. 92, 10 (2002) 5930–5935. [CrossRef] [Google Scholar]
- L. Liu, C. Caloz, T. Itoh, Dominant mode leaky-wave antenna with backfire-to-endfire scanning capability, Electron. Lett. 38, 23 (2002) 1414–1416. [CrossRef] [Google Scholar]
- F. Yang, Y. Rahmat-Samii, A low-profile circularly polarized curl antenna over an electromagnetic bandgap (EBG) surface, Microw. Opt. Tech. Lett. 31, 4 (2001) 264–267. [CrossRef] [Google Scholar]
- R. Gonzalo, P. de Maagt, M. Sorolla, Enhanced patch-antenna performance by suppressing surface waves using photonic-bandgap substrates, IEEE Trans. Microwave Theor. Tech. 47, 11 (1999) 2123–2130. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, N. Engheta (Guest Eds.), Special Issue on Metamaterials, IEEE Trans. Antennas Propag., 51, 10 (2003). [Google Scholar]
- T. Itoh, A.A. Oliner, Special Issue on Metamaterials, IEEE Trans. Microwave Theor. Tech. 53, 4 (2005). [Google Scholar]
- R.W. Ziolkowski, A.D. Kipple, Application of double negative metamaterials to increase the power radiated by electrically small antennas, IEEE Trans. Antennas Propag. 51, 10 (2003) 2626–2640. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, P. Jin, C.-C. Lin, Metamaterial-inspired engineering of antennas, Proc. IEEE 99, 10 (2011) 1720–1731. [CrossRef] [Google Scholar]
- A. Erentok, P. Luljak, R.W. Ziolkowski, Antenna performance near a volumetric metamaterial realization of an artificial magnetic conductor, IEEE Trans. Antennas Propag. 53, 1 (2005) 160–172. [CrossRef] [Google Scholar]
- A. Alú, N. Engheta, Pairing an epsilon-negative slab with a mu-negative slab: resonance, tunneling and transparency, IEEE Trans. Antennas Propag. 51, 10 (2003) 2558–2571. [CrossRef] [Google Scholar]
- A. Alú, N. Engheta, Plasmonic materials in transparency and cloaking problems: Mechanism, robustness and physical insights, Opt. Express 15, 6 (2007) 3318–3332. [CrossRef] [Google Scholar]
- A. Alú, N. Engheta, Plasmonic and metamaterial cloaking: physical mechanisms and potentials, J. Opt. A: Pure Appl. Opt. 10 (2008) 093002. [CrossRef] [Google Scholar]
- B. Edwards, M. Silveirinha, N. Engheta, Experimental verification of plasmonic cloaking at microwave frequencies with metamaterials, Phys. Rev. Lett. 103, 15 (2009) 153901. [CrossRef] [Google Scholar]
- D.F. Sievenpiper, J.H. Schaffner, H.J. Song, R.Y. Loo, G. Tangonan, Two-dimensional beam steering using an electrically tunable impedance surface, IEEE Trans. Antennas Propag. 51, 10 (2003) 2713–2722. [CrossRef] [Google Scholar]
- F. Yang, Y. Rahmat-Samii, Reflection phase characterizations of the EBG ground plane for low profile wire antenna applications, IEEE Trans. Antennas Propag. 51, 10 (2003) 2691–2703. [CrossRef] [Google Scholar]
- F. Yang, Y. Rahmat-Samii, Microstrip antennas integrated with electromagnetic band-gap (EBG) structures: A low mutual coupling design for array applications, IEEE Trans. Antennas Propag. 51, 10 (2003) 2936–2946. [CrossRef] [Google Scholar]
- F. Yang, Y. Rahmat-Samii, Electromagnetic Band Gap Structures in Antenna Engineering, Cambridge University Press, Cambridge, 2009. [Google Scholar]
- S. Clavijo, R.E. Diaz, W.E. McKinzie III, Design methodology for Sievenpiper high-impedance surfaces: An artificial magnetic conductor for positive gain electrically small antennas, IEEE Trans. Antennas Propag. 51, 10 (2003) 2678–2690. [CrossRef] [Google Scholar]
- G. Kiziltas, D. Psychoudakis, J.L. Volakis, N. Kikuchi, Topology design optimization of dielectric substrates for bandwidth improvement of a patch antenna, IEEE Trans. Antennas Propag. 51, 10 (2003) 2732–2743. [CrossRef] [Google Scholar]
- G. Mumcu, K. Sertel, J.L. Volakis, Miniature antennas and arrays embedded within magnetic photonic crystals, IEEE Antennas Wireless Propag. Lett. 5, 1 (2006) 168–171. [CrossRef] [Google Scholar]
- G. Mumcu, K. Sertel, J.L. Volakis, Miniature antenna using printed coupled lines emulating degenerate band edge crystals, IEEE Trans. Antennas Propag. 57, 6 (2009) 1618–1624. [CrossRef] [Google Scholar]
- J.L. Volakis, K. Sertel, Narrowband and wideband metamaterial antennas based on degenerate band edge and magnetic photonic crystals, Proc. IEEE 99, 10 (2011) 1732–1745. [CrossRef] [Google Scholar]
- H. Mosallaei, K. Sarabandi, Magneto-dielectrics in electromagnetics: Concept and applications, IEEE Trans. Antennas Propag. 52, 6 (2004) 1558–1567. [CrossRef] [Google Scholar]
- K. Buell, H. Mosallaei, K. Sarabandi, A substrate for small patch antennas providing tunable miniaturization factors, IEEE Trans. Microwave Theor. Tech. 54, 1 (2006) 135–146. [CrossRef] [Google Scholar]
- H. Mosallaei, K. Sarabandi, Design and modeling of patch antenna printed on magneto-dielectric embedded-circuit metasubstrate, IEEE Trans. Antennas Propag. 55, 1 (2007) 45–52. [CrossRef] [Google Scholar]
- M. Kashanianfard, K. Sarabandi, Metamaterial inspired optically transparent band-selective ground planes for antenna applications, IEEE Trans. Antennas Propag. 61, 9 (2013) 4624–4631. [CrossRef] [Google Scholar]
- C.L. Holloway, E.F. Kuester, J. Baker-Jarvis, P. Kabos, A double negative (DNG) composite medium composed of magnetodielectric spherical particles embedded in a matrix, IEEE Trans. Antennas Propag. 51, 10 (2003) 2596–2603. [CrossRef] [Google Scholar]
- E.F. Kuester, M.A. Mohamed, M. Piket-May, C.L. Holloway, Averaged transition conditions for electromagnetic fields at a metafilm, IEEE Trans. Antennas Propag. 51, 10 (2003) 2641–2651. [CrossRef] [Google Scholar]
- C.L. Holloway, A. Dienstfrey, E.F. Kuester, J.F. O’Hara, A.K. Azad, A.J. Taylor, A discussion on the interpretation and characterization of metafilms/metasurfaces: The two-dimensional equivalent of metamaterials, Metamaterials 3, 2 (2009) 100–112. [CrossRef] [Google Scholar]
- C.L. Holloway, E.F. Kuester, A. Dienstfrey, Characterizing metasurfaces/metafilms: The connection between surface susceptibilities and effective material properties, IEEE Antennas Wireless Propag. Lett. 10 (2011) 1507–1511. [CrossRef] [Google Scholar]
- C.L. Holloway, E.F. Kuester, J.A. Gordon, J. O’Hara, J. Booth, D.R. Smith, An overview of the theory and applications of metasurfaces: The two-dimensional equivalents of metamaterials, IEEE Antennas Propag. Mag. 54, 2 (2012) 10–35. [CrossRef] [Google Scholar]
- M.A. Antoniades, G.V. Eleftheriades, Compact linear lead/lag metamaterial phase shifters for broadband applications, IEEE Antennas Wireless Propag. Lett. 2, 1 (2003) 103–106. [CrossRef] [Google Scholar]
- Y. Horii, C. Caloz, T. Itoh, Super-compact multilayered left-handed transmission line and diplexer application, IEEE Trans. Microwave Theor. Tech. 53, 4 (2005) 1527–1534. [CrossRef] [Google Scholar]
- C. Caloz, T. Itoh, A. Rennings, CRLH metamaterial leaky-wave and resonant antennas, IEEE Antennas Propag. Mag. 50, 5 (2008) 25–39. [CrossRef] [Google Scholar]
- Y. Dong, T. Itoh, Metamaterial-based antennas, Proc. IEEE 100, 7 (2012) 2271–2285. [CrossRef] [Google Scholar]
- G.V. Eleftheriades, N. Engheta (Guest Eds.), Special Issue on metamaterials: fundamentals and applications in the microwave and optical regimes, Proc. IEEE, 99, 10 (2011). [CrossRef] [Google Scholar]
- Second DARPA MURI on Metamaterials. It was led by a Boeing Phantom Works (now Boeing Research and Technology) team. The principals at Boeing were Drs. M. Tanielian and C. Parazzoli. The university and national laboratory principals were: UCSD, S. Schultz and D. Vier; Duke, S. Cummer and D. Smith; U. Penn, N. Engheta; UAz, R.W. Ziolkowski; ISU, C. Soukoulis; UT Austin, G. Shvets; and NIST-Boulder, C. Holloway [Google Scholar]
- A. Erentok, R.W. Ziolkowski, J.A. Nielsen, R.B. Greegor, C.G. Parazzoli, M.H. Tanielian, S.A. Cummer, B.-I. Popa, T. Hand, D.C. Vier, S. Schultz, Low frequency lumped element-based negative index metamaterial, Appl. Phys. Lett. 91 (2007) 184104. [CrossRef] [Google Scholar]
- A. Erentok, R.W. Ziolkowski, J.A. Nielsen, R.B. Greegor, C.G. Parazzoli, M.H. Tanielian, S.A. Cummer, B.-I. Popa, T. Hand, D.C. Vier, S. Schultz, Lumped element-based, highly sub-wavelength negative index metamaterials at UHF Frequencies, J. Appl. Phys. 104, 3 (2008) 034901. [CrossRef] [Google Scholar]
- S.A. Tretyakov, Meta-materials with wideband negative permittivity and permeability, Microw. Opt. Technol. Lett. 31, 3 (2001) 163–165. [CrossRef] [Google Scholar]
- B.-I. Popa, S.A. Cummer, An architecture for active metamaterial particles and experimental validation at RF, Microw. Opt. Technol. Lett. 49, 10 (2007) 2574–2577. [CrossRef] [Google Scholar]
- Y. Yuan, B.-I. Popa, S.A. Cummer, Zero loss magnetic metamaterials using powered active unit cells, Opt. Express 17, 18 (2009) 16135–16143. [CrossRef] [Google Scholar]
- B.-I. Popa, S.A. Cummer, Nonreciprocal active metamaterials, Phys. Rev. B 85, 20 (2012) 205101. [CrossRef] [Google Scholar]
- S. Hrabar, I. Krois, A. Kiricenko, Towards active dispersionless ENZ metamaterial for cloaking applications, Metamaterials 4, 2 (2010) 89–97. [CrossRef] [Google Scholar]
- S. Hrabar, I. Krois, I. Bonic, A. Kiricenko, Negative capacitor paves the way to ultra-broadband metamaterials, Appl. Phys. Lett. 99, 25 (2011) 254103. [CrossRef] [Google Scholar]
- S. Hrabar, I. Krois, I. Bonic, A. Kiricenko, Ultra-broadband simultaneous superluminal phase and group velocities in non-Foster epsilon-near-zero metamaterial, Appl. Phys. Lett. 102, 5 (2013) 054108. [CrossRef] [Google Scholar]
- D.F. Sievenpiper, Superluminal waveguides based on non-Foster circuits for broadband leaky-wave antennas, IEEE Antennas Wireless Propag. Lett. 10 (2011) 231–234. [CrossRef] [Google Scholar]
- A.A. Zharov, I.V. Shadrivov, Y.S. Kivshar, Nonlinear properties of left-handed metamaterials, Phys. Rev. Lett. 91, 3 (2003) 037401. [CrossRef] [PubMed] [Google Scholar]
- I.V. Shadrivov, S.K. Morrison, Y.S. Kivshar, Tunable split-ring resonators for nonlinear negative-index metamaterials, Opt. Express 14, 20 (2006) 9344–9349. [CrossRef] [Google Scholar]
- D.A. Powell, I.V. Shadrivov, Y.S. Kivshar, M.V. Gorkunov, Self-tuning mechanisms of nonlinear split-ring resonators, Appl. Phys. Lett. 91, 14 (2007) 144107. [CrossRef] [Google Scholar]
- S. Saadat, M. Adnan, H. Mosallaei, E. Afshari, Composite metamaterial and metasurface integrated with non-Foster active circuit elements: A bandwidth-enhancement investigation, IEEE Trans. Antennas Propag. 61, 3 (2013) 1210–1218. [CrossRef] [Google Scholar]
- M. Barbuto, A. Monti, F. Bilotti, A. Toscano, Design of a non-Foster actively loaded SRR and application in metamaterial-inspired components, IEEE Trans. Antennas Propag. 61, 3 (2013) 1219–1227. [CrossRef] [Google Scholar]
- N. Zhu, R.W. Ziolkowski, Broad bandwidth, electrically small antenna augmented with an internal non-Foster element, IEEE Antennas Wireless Propag. Lett. 11 (2012) 1116–1120. [CrossRef] [Google Scholar]
- N. Zhu, R.W. Ziolkowski, Design and measurements of an electrically small, broad bandwidth, non-Foster circuit-augmented protractor antenna, Appl. Phys. Lett. 101 (2012) 024107. [CrossRef] [Google Scholar]
- M.-C. Tang, N. Zhu, R.W. Ziolkowski, Augmenting a modified Egyptian axe dipole antenna with non-Foster elements to enlarge its directivity bandwidth, IEEE Antennas Wireless Propag. Lett. 12 (2013) 421–424. [CrossRef] [Google Scholar]
- N. Zhu, R.W. Ziolkowski, Broad bandwidth, electrically small, non-Foster element-augmented antenna designs, analyses, and measurements, IEICE Trans. Commun. E96-B, 10 (2013) 2399–2409. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, M.-C. Tang, N. Zhu, An efficient, broad bandwidth, high directivity, electrically small antenna, Microw. Opt. Technol. Lett. 55, 6 (2013) 1430–1434. [CrossRef] [Google Scholar]
- H. Mirzaei, G.V. Eleftheriades, A resonant printed monopole antenna with an embedded non-Foster matching network, IEEE Trans. Antennas Propag. 61, 11 (2013) 5363–5371. [CrossRef] [Google Scholar]
- H. Mirzaei, G.V. Eleftheriades, Realizing non-Foster reactive elements using negative-group-delay networks, IEEE Trans. Microwave Theor. Tech. 61, 12 (2013) 4322–4332. [CrossRef] [Google Scholar]
- E. Ugarte-Munoz, S. Hrabar, D. Segovia-Vargas, A. Kiricenko, Stability of non-Foster reactive elements for use in active metamaterials and antennas, IEEE Trans. Antennas Propag. 60 (2012) 3490–3494. [CrossRef] [Google Scholar]
- Y. Fan, K.Z. Rajab, Y. Hao, Noise analysis of broadband active metamaterials with non-Foster loads, J. Appl. Phys. 113, 23 (2013) 233905. [CrossRef] [Google Scholar]
- H.-T. Chen, W.J. Padilla, J.M.O. Zide, A.C. Gossard, A.J. Taylor, R.D. Averitt, Active terahertz metamaterial devices, Nature 444 (2006) 597–600. [CrossRef] [PubMed] [Google Scholar]
- T.A. Klar, A.V. Kildishev, V.P. Drachev, V.M. Shalaev, Negative-index metamaterials: going optical, IEEE J. Sel. Top. Quantum Electron. 12, 6 (2006) 1106–1115. [CrossRef] [Google Scholar]
- S. Xiao, V.P. Drachev, A.V. Kildishev, X. Ni, U.K. Chettiar, H.-K. Yuan, V.M. Shalaev, Loss-free and active optical negative-index metamaterials, Nature 466, 7307 (2010) 735–738. [CrossRef] [Google Scholar]
- J.A. Gordon, R.W. Ziolkowski, The design and simulated performance of a coated nano-particle laser, Opt. Express 15 (2007) 2622–2653. [CrossRef] [Google Scholar]
- J.A. Gordon, R.W. Ziolkowski, Optical CNP metamaterials, Opt. Express 16 (2008) 6692–6716. [CrossRef] [PubMed] [Google Scholar]
- S. Arslanagić, R.W. Ziolkowski, Active coated nano-particle excited by an arbitrarily located electric Hertzian dipole – resonance and transparency effects, J. Opt. 12 (2010) 024014. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, S. Arslanagić, J. Geng, Where high-frequency engineering advances optics: active nanoparticles as nanoantennas, in: A. Alú, M. Agio (Eds.), Optical Antennas, Cambridge University Press, London, 2012, pp. 46–63, Chap. 4. [CrossRef] [Google Scholar]
- S. Arslanagić, R.W. Ziolkowski, Jamming of quantum emitters by active coated nano-particles, IEEE J. Sel. Top. Quantum Electron. 19, 3 (2013) 4800506. [CrossRef] [Google Scholar]
- N. Meinzer, M. Ruther, S. Linden, C.M. Soukoulis, G. Khitrova, J. Hendrickson, J.D. Olitzky, H.M. Gibbs, M. Wegener, Arrays of Ag split-ring resonators coupled to InGaAs single-quantum-well gain, Opt. Express 18, 23 (2010) 24140–24151. [CrossRef] [Google Scholar]
- Z. Huang, Th. Koschny, C.M. Soukoulis, Theory of pump-probe experiments of metallic metamaterials coupled to a gain medium, Phys. Rev. Lett. 108, 18 (2012) 187402. [CrossRef] [Google Scholar]
- O. Hess, J.B. Pendry, S.A. Maier, R.F. Oulton, J.M. Hamm, K.L. Tsakmakidis, Active nanoplasmonic metamaterials, Nature Mater. 11, 7 (2012) 573–584. [CrossRef] [PubMed] [Google Scholar]
- D. Schurig, J.J. Mock, B.J. Justice, S.A. Cummer, J.B. Pendry, A.F. Starr, D.R. Smith, Metamaterial electromagnetic cloak at microwave frequencies, Science 314, 5801 (2006) 977–980. [CrossRef] [PubMed] [Google Scholar]
- J.B. Pendry, D. Schurig, D.R. Smith, Controlling electromagnetic ﬁelds, Science 312, 5781 (2006) 1780–1782. [CrossRef] [MathSciNet] [PubMed] [Google Scholar]
- N.I. Landy, S. Sajuyigbe, J.J. Mock, D.R. Smith, W.J. Padilla, Perfect metamaterial absorber, Phys. Rev. Lett. 100, 20 (2008) 207402. [CrossRef] [PubMed] [Google Scholar]
- M.G. Silveirinha, N. Engheta, Theory of supercoupling, squeezing wave energy, and field confinement in narrow channels and tight bends using ε near-zero metamaterials, Phys. Rev. B 76, 24 (2007) 245109. [CrossRef] [Google Scholar]
- B. Edwards, A. Alù, M.E. Young, M. Silveirinha, N. Engheta, Experimental verification of epsilon-near-zero metamaterial coupling and energy squeezing using a microwave waveguide, Phys. Rev. Lett. 100, 3 (2008) 033903. [CrossRef] [Google Scholar]
- A. Sanada, C. Caloz, T. Itoh, Characteristics of the composite right/left-handed transmission lines, IEEE Microw. Wireless Compon. Lett. 14, 2 (2004) 68–70. [CrossRef] [Google Scholar]
- A. Lai, K.M.K.H. Leong, T. Itoh, Infinite wavelength resonant antennas with monopolar radiation pattern based on periodic structures, IEEE Trans. Antennas Propag. 55, 3 (2007) 868–876. [CrossRef] [Google Scholar]
- R.W. Ziolkowski, Propagation in and scattering from a matched metamaterial having a zero index of refraction, Phys. Rev. E 70 (2004) 046608. [CrossRef] [Google Scholar]
- A. Alù, M.G. Silveirinha, A. Salandrino, N. Engheta, Epsilon-near-zero metamaterials and electromagnetic sources: Tailoring the radiation phase pattern, Phys. Rev. B 75, 15 (2007) 155410. [CrossRef] [Google Scholar]
- N. Engheta, R.W. Ziolkowski (Eds.), Metamaterials – Physics and Engineering Explorations, Wiley-IEEE Press, Hoboken, NJ, 2006. [Google Scholar]
- G.V. Eleftheriades, K.G. Balmain (Eds.), Negative-Refraction Metamaterials, Wiley-IEEE Press, Hoboken, NJ, 2005. [CrossRef] [Google Scholar]
- C. Caloz, T. Itoh, Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications, Wiley-IEEE Press, Hoboken, NJ, 2005. [CrossRef] [Google Scholar]
Cite this article as: Ziolkowski RW: Metamaterials: The early years in the USA. EPJ Appl. Metamat. 2014, 1, 5.
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