D.H. Werner

Pennsylvania State University, University Park, Maryland, United States

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Publications (495)602.11 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The theoretical basis for an ultra-thin broadband absorber is established which is comprised of a mushroom-type high impedance surface (HIS) and a pixelized frequency selective surface (FSS). The latter is engineered to exhibit a prescribed series circuit response and it is placed at an electrically small distance above the HIS. Through a transmission line analysis, it is demonstrated that the admittances of the two structures cancel each other, resulting in an almost zero input reactance and a resistance that fluctuates around that of free space within the frequency range of interest. The resulting structure has a total thickness that does not exceed 2 mm while a return loss is achieved for normal incidence from .
    IEEE Antennas and Wireless Propagation Letters 11/2015; 14:1-1. DOI:10.1109/LAWP.2015.2390145 · 1.58 Impact Factor
  • Zhi Hao Jiang · Douglas H. Werner
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    ABSTRACT: A compact circularly polarized (CP) co-designed filtering antenna is reported. The device is based on a patch radiator seamlessly integrated with a bandpass filter composed of coupled stripline open-loop resonators, which are designed together as a system. In the proposed design, the patch functions simultaneously as the radiator and the last stage resonator of the filter, resulting in a low-profile integrated radiating and filtering module with a small overall form factor of . It is shown that the filtering circuit not only ensures frequency selectivity but also provides impedance matching functionality, which serves to broaden both the impedance and axial ratio bandwidths. The designed filtering antenna was fabricated and measured, experimentally achieving an , an axial ratio of less than 3 dB and a gain higher than 5.2 dBi over a bandwidth from 3.77 to 4.26 GHz, i.e., around 12.2%, which makes it an excellent candidate for integration into a variety of wireless systems. A linearly polarized version of the integrated filtering antenna was also demonstrated. In addition, further full-wave simulations and experiments were carried out to verify that the designed CP filtering antenna maintains its properties even when mounted on different positions of the human body with various body gestures. The stable impedance and radiation properties also make it a suitable candidate as a wearable antenna for off-body wireless communications.
    IEEE Transactions on Antennas and Propagation 09/2015; 63(9):3808-3818. DOI:10.1109/TAP.2015.2452942 · 2.18 Impact Factor
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    ABSTRACT: Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 08/2015; 373(2049). DOI:10.1098/rsta.2014.0363 · 2.15 Impact Factor
  • Jeremiah P. Turpin · Douglas H. Werner · Douglas E. Wolfe
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    ABSTRACT: Spatial tuning of a volumetric metamaterial introduces many new design considerations that strongly affect the performance and practicality of a resulting system implementation. This paper discusses the design rules and procedures for spatially reconfigurable metamaterial systems using a tunable near-zero-index slab with adjustable shape as a representative design example. We propose a split-ring resonator-based metamaterial where each resonator is tuned in and out of resonance using a varactor diode to change the effective material response. The periodic, hexagonal tiles may be combined and connected in a planar spiral to form a cylindrical metamaterial panel whose radius may be arbitrarily large. Multiple panels are then stacked, with appropriate cropping, to form a volumetric metamaterial slab.
    IEEE Transactions on Antennas and Propagation 08/2015; 63(8):1-1. DOI:10.1109/TAP.2015.2431718 · 2.18 Impact Factor
  • Lei Kang · Zhi Hao Jiang · Taiwei Yue · Douglas H Werner
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    ABSTRACT: We provide the first experimental demonstration of the handedness dependent electromagnetically induced transparency (EIT) in chiral metamaterials during the interaction with circularly polarized waves. The observed chiral-sensitive EIT phenomena arise from the coherent excitation of a non-radiative mode in the component split ring resonators (SRRs) produced by the corresponding Born-Kuhn type (radiative) resonators that are responsible for the pronounced chirality. The coherent coupling, which is dominated by the bonding and antibonding resonances of the Born-Kuhn type resonators, leads to an extremely steep dispersion for a circularly polarized wave of predefined handedness. Accordingly, retrieved effective medium parameters from simulated results further reveal a difference of 80 in the group indices for left- and right-handed circularly polarized waves at frequencies within the EIT window, which can potentially result in handedness-sensitive pulse delays. These chiral metamaterials which enable a handedness dependent EIT effect may provide more degrees of freedom for designing circular polarization based communication devices.
    Scientific Reports 07/2015; 5:12224. DOI:10.1038/srep12224 · 5.58 Impact Factor
  • Zhi Hao Jiang · Micah D Gregory · Douglas H Werner
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    ABSTRACT: A compact circularly polarized (CP) integrated filtering antenna is reported for wearable biotelemetric devices in the 2.4 GHz ISM band. The design is based on a mutual synthesis of a CP patch antenna connected to a bandpass filter composed of coupled stripline open-loop resonators, which provides an integrated low-profile radiating and filtering module with a compact form factor of 0.44λ0×0.44λ0×0.04λ0. The optimized filtering antenna is fabricated and measured, achieving an , an axial ratio of less than 3 dB and gain higher than 3.5 dBi in the targeted ISM band. With the integrated filtering functionality, the antenna exhibits good out-of-band rejection over an ultra-wide frequency range of 1-6 GHz . Further full-wave simulations and experiments were carried out, verifying that the proposed filtering antenna maintains these desirable properties even when mounted in close proximity to the human body at different positions. The stable impedance performance and the simultaneous wide axial ratio and radiated power beam widths make it an ideal candidate as a wearable antenna for off-body communications. The additional integrated filtering functionality further improves utility by greatly reducing interference and crosstalk with other existing wireless systems.
    IEEE Transactions on Biomedical Circuits and Systems 07/2015; DOI:10.1109/TBCAS.2015.2438551 · 2.48 Impact Factor
  • G. Oliveri · D.H. Werner · A. Massa
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    ABSTRACT: The introduction of electromagnetic (EM) media with unique field manipulation properties, collectively labelled as metamaterials, has boosted the interest toward the design, the fabrication, and the testing of artificial materials whose features can be engineered according to the applicative requirements and user objectives. In this framework, the long-term promise of reconfigurable metamaterial theory (i.e., the possibility to change the EM response of a 2-D/3-D material arbitrarily and in real time) has given the designers an extremely wide number of new degrees of freedom for the synthesis of innovative adaptive systems. Moreover, successful experimental validations of reconfigurable metamaterials in the entire EM spectrum from microwaves to optical frequencies have further stimulated academic and industrial interests in developing devices with enhanced performances, efficiency, and robustness. Nevertheless, the exploitation of reconfigurable metamaterials in commercial devices is still an open problem with several challenges from both the theoretical and technological viewpoints. This paper is then aimed at reviewing the latest advances on reconfigurable metamaterial engineering from the methodological perspective also providing a comprehensive and balanced survey on latest concepts, current trends, and envisaged future developments on this active field of research.
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    ABSTRACT: Chiral-selective nonlinear optics and optoelectronic signal generation are demonstrated in an electrically active photonic metamaterial. The metamaterial reveals significant chiroptical responses in both the harmonic generation and photon drag effect, correlated to the resonance behavior in the linear regime. The multifunctional chiral metamaterial with dual electrical and optical functionality enables transduction of chiroptical responses to electrical signals for integrated photonics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Advanced Materials 06/2015; 27(29). DOI:10.1002/adma.201501930 · 17.49 Impact Factor
  • Micah D. Gregory · Spencer V. Martin · Douglas H. Werner
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    ABSTRACT: The covariance matrix adaptation evolutionary strategy (CMA-ES) is explored here as an improved alternative to well-established algorithms used in electromagnetic (EM) optimization. In the past, methods such as the genetic algorithm (GA), particle swarm optimization (PSO), and differential evolution (DE) have commonly been used for EM design. In this article, we examine and compare the performance of CMA-ES, PSO, and DE when applied to test functions and several challenging EM design problems. Of particular interest is demonstrating the ability of the relatively new CMA-ES to more quickly and more reliably find acceptable solutions compared with those of the more classical optimization strategies. In addition, it will be shown that due to its self-adaptive scheme, CMA-ES is a more user-friendly algorithm that requires less knowledge of the problem for preoptimization configuration.
    IEEE Antennas and Propagation Magazine 06/2015; 57(3):48-59. DOI:10.1109/MAP.2015.2437277 · 1.32 Impact Factor
  • Zhi Hao Jiang · Peter E. Sieber · Lei Kang · Douglas H. Werner
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    ABSTRACT: The concept of invisibility has garnered long-standing interest throughout human history but has only been realized experimentally within the past decade, albeit over a limited bandwidth. While the physical wave phenomenon of a reduced scattering signature has been demonstrated with different cloaking methods such as transformation optics and scattering cancellation, such technology has yet to be incorporated into any practical real-world devices. Through the use of quasi-2D functional metasurfaces, the long-standing issue of simultaneous mutual coupling and radiation blockage is addressed that occurs when two or more electromagnetic radiators are placed in close proximity to one another. The proposed compact and ultralightweight metasurfaces, comprising arrays of subwavelength electric and magnetic resonators with tailored dispersive properties, are capable of fully restoring the intrinsic properties of real-world electromagnetic radiators when placed in a multiradiator environment. This work introduces a general design approach to bridge the gap between the theory and practice for cloaks, which is applicable to microwave, terahertz, and optical radiators, as well as acoustic and thermal sources. Moreover, this technology provides an unprecedented opportunity for enabling high-density deployment of radiating systems with low interference and undistorted signal wave fronts.
    Advanced Functional Materials 06/2015; 25(29). DOI:10.1002/adfm.201501261 · 11.81 Impact Factor
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    ABSTRACT: Recent developments in transformation optics have led to burgeoning research on gradient index lenses for novel optical systems. Such lenses hold great potential for the advancement of complex optics for a wide range of applications. Despite the plethora of literature on gradient index lenses, previous works have not yet considered the application of anti-reflective coatings to these systems. Reducing system reflections is crucial to the development of this technology for highly sensitive optical applications. Here, we present effective anti-reflective-coating designs for gradient index lens systems. Conventional anti-reflective-design methodologies are leveraged in conjunction with transformation optics to develop coatings that significantly reduce reflections of a flat gradient index lens. Finally, the resulting gradient-index anti-reflective coatings are compared and contrasted with conventional homogeneous anti-reflective coatings.
    Optics Letters 06/2015; 40(11):2521-2524. DOI:10.1364/OL.40.002521 · 3.29 Impact Factor
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    ABSTRACT: The optical properties of a dimer type nanoantenna loaded with a plasmonic nanoring are investigated through numerical simulations and measurements of fabricated prototypes. It is demonstrated that by judiciously choosing the nanoring geometry it is possible to engineer its electromagnetic properties and thus devise an effective wavelength dependent nanoswitch. The latter provides a mechanism for controlling the coupling between the dimer particles, and in particular to establish a pair of coupled/de-coupled states for the total structure, that effectively results in its dual mode response. Using electron beam lithography the targeted structure has been accurately fabricated and the desired dual mode response of the nanoantenna was experimentally verified. The response of the fabricated structure is further analyzed numerically. This permits the visualization of the electromagnetic fields and polarization surface charge distributions when the structure is at resonance. In this way the switching properties of the plasmonic nanoring are revealed. The documented analysis illustrates the inherent tuning capabilities that plasmonic nanorings offer, and furthermore paves the way towards a practical implementation of tunable optical nanoantennas. Additionally, our analysis through an effective medium approach introduces the nanoring as a compact and efficient solution for realizing nanoscale circuits.
    Scientific Reports 05/2015; 5:9813. DOI:10.1038/srep09813 · 5.58 Impact Factor
  • Anastasios H. Panaretos · Douglas H. Werner
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    ABSTRACT: In this paper we theoretically investigate the feasibility of creating a dual-mode plasmonic nanorod antenna. The proposed design methodology relies on adapting to optical wavelengths the principles of operation of trapped dipole antennas, which have been widely used in the low MHz frequency range. This type of antenna typically employs parallel LC circuits, also referred to as “traps”, which are connected along the two arms of the dipole. By judiciously choosing the resonant frequency of these traps, as well as their position along the arms of the dipole, it is feasible to excite the λ/2 resonance of both the original dipole as well as the shorter section defined by the length of wire between the two traps. This effectively enables the dipole antenna to have a dual-mode of operation. Our analysis reveals that the implementation of this concept at the nanoscale requires that two cylindrical pockets (i.e. loading volumes) be introduced along the length of the nanoantenna, inside which plasmonic core-shell particles are embedded. By properly selecting the geometry and constitution of the core-shell particle as well as the constitution of the host material of the two loading volumes and their position along the nanorod, the equivalent effect of a resonant parallel LC circuit can be realized. This effectively enables a dual-mode operation of the nanorod antenna. The proposed methodology introduces a compact approach for the realization of dual-mode optical sensors while at the same time it clearly illustrates the inherent tuning capabilities that core-shell particles can offer in a practical framework.
    Optics Express 04/2015; 23(7). DOI:10.1364/OE.23.008298 · 3.49 Impact Factor
  • Source
    Anastasios H. Panaretos · Douglas H. Werner
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    ABSTRACT: In this paper we demonstrate the feasibility of using multiport network theory to describe the admittance properties of a longitudinally loaded plasmonic nanorod antenna. Our analysis reveals that if the appropriate terminal ports are defined across the nanorod geometry then the corresponding voltage and current quantities can be probed and thus it becomes feasible to extract the admittance matrix of the structure. Furthermore, it is demonstrated that by utilizing cylindrical dielectric waveguide theory, closed form expressions can be derived that uniquely characterize the loading material in terms of its admittance. The combination of the admittance matrix information along with the load admittance expressions provides an effective methodology for computing the nanorod’s input admittance/impedance for arbitrary loading scenarios. This is important because the admittance resonances are associated with the structure’s scattering peaks which are excited by a plane wave polarized parallel to its long dimension. Subsequently, the proposed approach provides a fast and computationally efficient circuit-based methodology to predict and custom engineer the scattering properties of a loaded plasmonic nanorod without having to rely on repetitive lengthy full wave simulations.
    Optics Express 02/2015; 23(4). DOI:10.1364/OE.23.004459 · 3.49 Impact Factor
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    ABSTRACT: An efficient procedure for modeling medium frequency (MF) communications in coal mines is introduced. In particular, a hybrid approach is formulated and demonstrated utilizing ideal transmission line equations to model MF propagation in combination with full-wave sections used for accurate simulation of local antenna-line coupling and other near-field effects. This work confirms that the hybrid method accurately models signal propagation from a source to a load for various system geometries and material compositions, while significantly reducing computation time. With such dramatic improvement to solution times, it becomes feasible to perform large-scale optimizations with the primary motivation of improving communications in coal mines both for daily operations and emergency response. Furthermore, it is demonstrated that the hybrid approach is suitable for modeling and optimizing large communication networks in coal mines that may otherwise be intractable to simulate using traditional full-wave techniques such as moment methods or finite-element analysis.
    IEEE Antennas and Propagation Magazine 02/2015; 57(1):164-176. DOI:10.1109/MAP.2015.2397157 · 1.32 Impact Factor
  • Micah D. Gregory · Douglas H. Werner
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    ABSTRACT: The recently popularized memristor, short for memory resistor, is investigated in this paper for its potential as a new and attractive method for enabling reconfigurable radio-frequency (RF) devices. The charge- or flux-controlled resistance of this “fourth circuit element” allows for easy reconfigurability and maintains its configured state in the absence of controlling signals. A specialized finite-difference time-domain simulation code is developed and employed to design devices with embedded memristors. The time-domain code allows observation of the nonlinear memristor switching characteristics and real-time functionality of the reconfigurable device. Several different reconfigurable RF devices are designed here to demonstrate the versatility of the memristor and determine the behavior of systems which utilize them.
    IEEE Antennas and Propagation Magazine 02/2015; 57(1):239-248. DOI:10.1109/MAP.2015.2397153 · 1.32 Impact Factor
  • Source
    P. E. Sieber · D. H. Werner
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    ABSTRACT: In this work a new technique for synthesizing metamaterials using Bézier surfaces is introduced. First, the computational efficiency for the optimization of a reconfigurable Bézier quarter-wave plate metasurface is compared to the popular technique of optimizing pixelized surfaces via a binary Genetic Algorithm (GA). For the presented design methodology, a real valued optimization technique is employed which is based on the Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES). When compared to the GA, the optimizations of Bézier surfaces using CMA-ES are shown to consistently arrive at better solutions with an order of magnitude reduction in the required number of function evaluations. Additionally, more examples of Bézier metasurfaces are presented in the form of broadband quarter-wave and half-wave plate designs operating at optical wavelengths, subsequently exhibiting bandwidths which outperform metasurface designs found in the current literature.
    Optics Express 12/2014; 22(26). DOI:10.1364/OE.22.032371 · 3.49 Impact Factor
  • Source
    Zhi Hao Jiang · Lan Lin · Ding Ma · Seokho Yun · Douglas H Werner · Zhiwen Liu · Theresa S Mayer
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    ABSTRACT: Quasi two-dimensional metasurfaces composed of subwavelength nanoresonator arrays can dramatically alter the properties of light in an ultra-thin planar geometry, enabling new optical functions such as anomalous reflection and refraction, polarization filtering, and wavefront modulation. However, previous metasurface-based nanostructures suffer from low efficiency, narrow bandwidth and/or limited field-of-view due to their operation near the plasmonic resonance. Here we demonstrate plasmonic metasurface-based nanostructures for high-efficiency, angle-insensitive polarization transformation over a broad octave-spanning bandwidth. The structures are realized by optimizing the anisotropic response of an array of strongly coupled nanorod resonators to tailor the interference of light at the subwavelength scale. Nanofabricated reflective half-wave and quarter-wave plates designed using this approach have measured polarization conversion ratios and reflection magnitudes greater than 92% over a broad wavelength range from 640 to 1290 nm and a wide field-of-view up to ±40°. This work outlines a versatile strategy to create metasurface-based photonics with diverse optical functionalities.
    Scientific Reports 12/2014; 4:7511. DOI:10.1038/srep07511 · 5.58 Impact Factor
  • Zhi Hao Jiang · Douglas H. Werner
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    ABSTRACT: Low-profile and light-weight coatings that offer comprehensive manipulation of the electromagnetic scattering for finite-length objects are highly desirable, but not yet achieved, for applications including camouflaging, deceptive sensing, radar cognition control, and defense security. Here, for the first time, the theory, practical design, and experimental demonstration of quasi-three-dimensional and angle-tolerant electromagnetic illusion coatings are presented which have been enabled by ultrathin single-layer functional metasurfaces. By controlling the multiple Mie scattering coefficients using the tangential and non-vanishing radial electromagnetic responses of the metasurface, the quasi-two-dimensional coating transforms the electromagnetic perception of one object to mimic that of another which has been pre-selected by the designer. The illusion coating, which is homogeneous but anisotropic, is realized using hundreds of composite electric and magnetic sub-wavelength unit cells operating at frequencies away from their resonance. Two different prototypes of the metasurface illusion coatings were fabricated and characterized, demonstrating very good camouflaging performance for finite-length dielectric as well as conducting objects within a field-of-view up to ±10° off normal. This work paves the way for practical artificially engineered material coatings with exotic and versatile scattering control capabilities that would enable a wide range of applications throughout the entire electromagnetic spectrum.
    Advanced Functional Materials 12/2014; 24(48). DOI:10.1002/adfm.201401561 · 11.81 Impact Factor

Publication Stats

5k Citations
602.11 Total Impact Points


  • 1991–2015
    • Pennsylvania State University
      • • Department of Electrical Engineering
      • • Applied Research Laboratory
      • • College of Engineering
      University Park, Maryland, United States
  • 2006–2014
    • William Penn University
      Worcester, Massachusetts, United States
    • York College of PA
      State College, Pennsylvania, United States
  • 2011
    • Northrop Grumman
      Falls Church, Virginia, United States
  • 2004–2010
    • University of Granada
      • Departamento de Electromagnetismo y Física de la Materia
      Granada, Andalusia, Spain
  • 2009
    • University of Massachusetts Amherst
      • Department of Electrical and Computer Engineering
      Amherst Center, MA, United States
  • 2007
    • Urmia University
      Rezâiyye, Āz̄ārbāyjān-e Gharbī, Iran
  • 2003–2004
    • University of Massachusetts Lowell
      • Department of Electrical & Computer Engineering
      Lowell, MA, United States
    • Università di Pisa
      • Department of Information Engineering
      Pisa, Tuscany, Italy