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We present a general-purpose end-to-end image chain simulation (ICS) that enables to assess the image quality of a satellite imager for Earth observations. The image chain consists of four main components: radiometry, atmosphere, optics, and detector. In particular, ICS first computes the input radiance from the reflectance values of a high-resolution input, and then calculates the image radiance by using the optical transfer function (OTF) of the overall system. This OTF contains all the distortion effects due to atmosphere, optics, and detector. Finally, the signal on the detector, including the noise term, is computed and converted to digital counts. To evaluate the overall image quality, metrics such as peak signal-to-noise ratio and minimum resolvable contrast are used. To illustrate the utility and versatility of the developed ICS, several analyses are also performed that demonstrate the system performance of a generic satellite imagery. Our development provides a unified framework for the ICS developers of spaceborne Earth-observing systems. Such a complete end-to-end ICS is crucial for the effective development of an Earth observation satellite, especially in the design and test phases.

Temperature-sensitive scattering of terahertz (THz) waves by infinitely long, cylindrical core-shell structures was theoretically studied. Each structure is a dielectric cylinder coated with an InSb shell illuminated by either a transverse-electric (TE) or a transverse-magnetic (TM) plane wave. InSb is a thermally tunable semiconductor showing a transition from dielectric to plasmonic state at THz frequencies. Accordingly, the total scattering efficiency (TSE) can be thermally tuned for both polarization states of the incident plane wave. The spectral locations of the maxima and minima of the TSE of an InSb-coated cylinder can be exploited for cloaking the core. At least three scenarios lead to the strong suppression of scattering by a single core-shell structure in different spectral regimes when the temperature is fixed. The excitation of localized surface-plasmon resonances is the feature being common for two of them, while the effect of volumetric resonance dominates in the third scenario. Regimes that are either highly or weakly sensitive to the core material were identified. Weak sensitivity enables masking, i.e., the core material cannot be identified by a far-zone observer. The TSE minima are usually significantly sensitive to the polarization state, but ones with weak sensitivity to the polarization state also exist. (c) 2018 Optical Society of America

We present the optical transfer function (OTF) analysis of a spaceborne imaging sensor. This includes the effects of detector footprint, diffusion, smear, jitter, sampling, and time delay and integration. Each effect is analyzed under various design choices one of which corresponds to our designed complementary metal-oxide semiconductor imaging sensor. Effect of each subsystem is separately demonstrated using OTF values and corresponding degradation on a test image.

Electromagnetically induced transparency and polarization conversion due to interference between two polarization-selective plasmonic resonances coexisting in the same planar metamaterial are studied. The metasurface represents a periodic array of two topologically distinct metamolecules combined on the same substrate: i ) monopole antennas connected to wires and supporting a high-Q resonance radiatively coupled to x -polarization, and ii ) dipolar antennas supporting a low-Q resonance coupled to y -polarization. We demonstrate that due to the interaction between these modes through a capacitive coupling between the metamolecules, one can observe a circularly-polarized Electromagnetically Induced Transparency (EIT) and thereby achieve an efficient ultra-thin quarter-wave plate.

In this paper, we present the design of miniaturized narrowband-microwave absorbers based on different kinds of magnetic inclusions. The operation of the proposed components originates from the resonance of a planar array of inclusions excited by an incoming wave with a given polarization. As in common absorber layouts, a 377 Omega resistive sheet is also used to absorb the electromagnetic energy of the impinging field. Since the planar array of magnetic inclusions behaves at its resonance as a perfect magnetic conductor, the resistive sheet is placed in close proximity of the resonating inclusions, without perturbing their resonance condition. In contrast to other typical absorber configurations presented in the literature, the absorber proposed in this paper is not backed by a metallic plate. This feature may be useful for stealth applications, as discussed thoroughly in the paper. The other interesting characteristic of the proposed absorbers is the subwavelength thickness, which has shown to depend only on the geometry of the basic resonant inclusions employed. At first, regular split-ring resonators (SSRs) disposed in an array configuration are considered and some application examples are presented. Absorbers based on SRRs are shown to reach thickness of the order of lambda(0)/20. In order to further squeeze the electrical thickness of the absorbers, multiple SRRs and spiral resonators are also used. The employment of such inclusions leads to the design of extremely thin microwave absorbers, whose thickness may even be close to lambda(0)/100. Finally, some examples of miniaturized absorbers suitable for a practical realization are proposed.

We demonstrate an electrically small antenna that operates at two modes, which correspond to two orthogonal polarizations. The antenna was single fed and composed of perpendicularly placed metamaterial elements and a monopole. One of the metamaterial elements was a multi split ring resonator (MSRR), and the other one was a split ring resonator (SRR). The elements' physical sizes were the same while the electrical sizes differed nearly by 1 GHz. This variety resulted in the dual mode operation at the 4.72 GHz and 5.76 GHz frequencies. When the antenna operated in the MSRR mode at 4.72 GHz for one polarization, it simultaneously operated for the SRR mode at 5.76 GHz, but for the perpendicular polarization. The efficiencies of the modes were 15% and 40%, and electrical sizes were lambda/11.2 and lambda/9.5, correspondingly. Finally, we numerically demonstrate the effect of coupling of the two resonators on the operation frequencies.

We numerically and experimentally investigate a planar metamaterial that is composed of connected cut-wire pairs and continuous wires operating at 21 GHz. The characterization was performed by using the effective medium theory. The existence of negative refraction is concluded from the transmission data of four structures: cut-wire pairs, shorted cut-wire pairs, composite metamaterial, and shorted composite metamaterial.

We studied the far field radiation properties of a new resonator antenna composed of split ring resonators (SRRs) and a monopole. It is shown that the antenna size at the operation frequency (3.52 GHz) is approximately one tenth of the free space wavelength (λ/10). Moreover, increasing the number of SRRs yields steerability properties. These achievements provide a way to create rather small steerable resonant antennas.

The effect of the material absorption factor on terahertz absorption (A), transmittance (T), and reflectance (R) for slabs of PhC that comprise rods made of GaAs, a polar dielectric, is studied. The main goal was to illustrate how critical a choice of the absorption factor for simulations is and to indicate the importance of the possible modification of the absorption ability by using either active or lossy impurities. The spectra of A, T, and R are strongly sensitive to the location of the polaritonic gap with respect to the photonic pass and stop bands connected with periodicity that enables the efficient combination of the effects of material and structural parameters. It will be shown that the spectra can strongly depend on the utilized value of the material absorption factor. In particular, both narrow and wide absorption bands may appear owing to a variation of the material parameters with a frequency in the vicinity of the polaritonic gap. The latter are often achieved at wideband suppression of transmission, so that an ultra-wide stop band can appear as a result of adjustment of the stop bands having different origin. The results obtained at simultaneous variation of the absorption factor and frequency, and angle of incidence and frequency, indicate the possibility of the existence of wide ranges of tolerance, in which the basic features do remain. This allows for mitigating the accuracy requirements for the absorption factor in simulations and promises the efficient absorption of nonmonochromatic waves and beams with a wide angular spectrum. Suppression of narrowband effects in transmission is demonstrated at rather large values of the absorption factor, when they appear due to either the defect modes related to structural defects or dispersion inspired variations of the material parameters in the vicinity of the polaritonic gap. Comparison with auxiliary structures helps one to detect the common features and differences of homogeneous slabs and slabs of a PhC, which are made of GaAs. (C) 2015 AIP Publishing LLC.

We studied periodic aperture imaging with various subaperture configurations in terms of their point spread functions, optical transfer functions, and imaging quality. A circular-shaped unit cell provides the best performance compared to square- and cross-shaped unit cells when the total aperture size and collection area are kept the same. Moreover, decreasing the separation among the unit cells or the number of subapertures also improve the imaging performance. Results have potential applications in optical periodic aperture telescopes, diffraction masks, and coded aperture imaging. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

In the present study, we first demonstrate the polarization and orientation dependent transmission response of split ring resonators at the infrared and visible band. Then, we numerically demonstrate a configuration for the enhancement of power passing through an electrically small hole. By using deep subwavelength optical split ring resonator antennas and couplers we achieved a 400-fold enhanced transmission from a subwavelength aperture area of the electrical size λ2/25. The power was transmitted to the far field with 3.9 dBi directivity at 300 THz. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present spectral hybridization of organic and inorganic resonant materials and related bio-sensing mechanism. We utilized a bound protein (streptavidin) and a Fano-resonant metasurface to illustrate the concept. The technique allows us to investigate the vibrational modes of the streptavidin and how they couple to the underlying metasurface. This optical, label-free, nonperturbative technique is supported by a coupled mode-theory analysis that provides information on the structure and orientation of bound proteins. We can also simultaneously monitor the binding of analytes to the surface through monitoring the shift of the metasurface resonance. All of this data opens up interesting opportunities for applications in biosensing, molecular electronics and proteomics. © 2014 IEEE.

Hybridization of dominant vibrational modes with meta-surface resonance allows detection of both structural changes and surface orientations of bound helical peptides. Depending on the resonance frequency of meta-molecules, a red- or blue- shift in peptide Amide-I frequency is observed. The underlying coupling mechanism is described by using a temporal coupled mode theory that is in very good agreement with the experimental results. This hybridization phenomenon constitutes the basis of many nanophotonic systems such as tunable coupled mode bio-sensors and dynamic peptide systems driven by infrared signals.

Graphene is widely known for its anomalously strong broadband optical absorptivity of 2.3% that enables seeing its single-atom layer with the naked eye. However, in the mid-infrared part of the spectrum graphene represents a quintessential lossless zero-volume plasmonic material. We experimentally demonstrate that, when integrated with Fano-resonant plasmonic metasurfaces, single-layer graphene (SLG) can be used to tune their mid-infrared optical response. SLG’s plasmonic response is shown to induce large blue shifts of the metasurface’s resonance without reducing its spectral sharpness. This effect is explained by a generalized perturbation theory of SLG-metamaterial interaction that accounts for two unique properties of the SLG that set it apart from all other plasmonic materials: its anisotropic response and zero volume. These results pave the way to using gated SLG as a platform for dynamical spectral tuning of infrared metamaterials and metasurfaces.

We demonstrate theoretically and experimentally that electrically gated single-layer graphene can be used to inductively tune the infrared optical response of Fano-resonant meta-surfaces. Several implementations will be introduced: graphene of the meta-surface, graphene directly under the meta-surface, and graphene separated by a thin spacer from the meta-surface. Both electrostatic and chemical doping of graphene will be discussed and supporting experimental results presented. Finally, we will demonstrate how the spectral shifts of metamaterials resonances introduced by the graphene can be utilized to extract graphene's electronic properties such as the complex-valued resistivity.

Cataloged from PDF version of article. Strongly asymmetric Fabry-Perot-type transmission arising at the two-way coupling has been studied in the case of normal incidence for slabs of two-dimensional photonic crystals (PCs) with one-sided corrugations that are made of linear isotropic materials. Comparing to the scenario of unidirectional transmission known for the structures with broken spatial inversion symmetry that requires zero order being uncoupled, in the studied mechanism zero order is either the sole order or one of the orders that may be coupled to a Floquet-Bloch mode. Contrary to the earlier studies of asymmetric transmission at the coupled zero order, structures with nondeep corrugations are considered, which allow one to combine Fabry-Perot-type total-transmission maxima with diffractions in a desired way. At a proper choice of PC lattice and corrugation parameters, higher orders can dominate in Fabry-Perot-type transmission at the noncorrugated-side illumination and also at the total-transmission maxima, whereas only zero order contributes to the transmission at the corrugated-side illumination. As a result, strong asymmetry can be obtained without uncoupling of zero order but it invokes the unidirectional contribution of higher orders. The presented results show that the entire structure can be approximately decomposed into the two independent, regular and grating (nonregular), parts whose contributions to the transmission are additive. Multiple asymmetric transmission maxima can coexist with a rather high equivalent group index of refraction. Possible applications of the studied transmission mechanism are discussed.

A composite chiral metamaterial (CCMM) is designed and studied both numerically and experimentally. The CCMM is constructed by the combination of a continuous metallic wires structure and a purely chiral metamaterial (CMM) that consists of conjugated Rosettes. For the CMM, only very small, useful bands of negative index can be obtained for circularly polarized waves. These bands are all above the chiral resonance frequencies because of the high value of the effective parameter of relative permittivity epsilon. After the addition of the continuous metallic wires, which provide negative permittivity, the high value of epsilon can be partially compensated. Thus, a negative index band for the left circularly polarized wave that is below the chiral resonance frequency is obtained for the CCMM. At the same time, a negative index band for the right circularly polarized wave that is above the chiral resonance frequency is also obtained. Furthermore, both negative index bands correspond to the transmission peaks and have high values of the figure of merit. Therefore, the CCMM design that is proposed here is more suitable than the CMM for the construction of chiral metamaterials with a negative index. (C) 2012 Optical Society of America

Cataloged from PDF version of article. In the present study, we provide a detailed analysis for the study of photonic metamaterials. We demonstrate the polarization and orientation dependent transmission response of split ring resonators at the infrared and visible band. We provided optical measurements only for one case, in which electric component of the incident field was coupled to planar split ring resonator array. We consecutively studied (i) frequency tuning, (ii) effect of resonator density, (iii) shifting magnetic resonance frequency by changing the resonator shape, and (iv) effect of metal loss and plasma frequency. The study provides an overlook for the candidate applications such as the enhancement of power passing through an electrically small hole, negative index metamaterials and optical metamaterial absorbers. (C) 2010 Elsevier B.V. All rights reserved.

A complementary bilayer cross-wire chiral metamaterial is proposed and studied experimentally and numerically. It exhibits giant optical activity and a small circular dichroism. The retrieval results reveal that a negative refractive index is realized for right circularly polarized waves due to the strong chirality. Our numerical results show that the mechanism of the chiral behavior at the resonance of lower frequency can be interpreted as the coupling effects between two sets of mutually twisted virtual magnetic dipoles, while the resonance of higher frequency shows complicated nonlocal features. (C) 2011 American Institute of Physics. [doi:10.1063/1.3574909]

In this chapter, the role of complex artificial structures in enhancing the power transmission through sub-wavelength apertures is discussed. Such devices are aimed at exciting highly localized resonances in order to increase the aperture equivalent magnetic and electric dipole moments. Some examples, based on epsilon-near-zero metamaterials (ENZ), frequency selective surfaces (FSSs) and split-ring resonators (SRRs) at microwaves, and silver nano-particle pairs at terahertz scale, are presented. Such structures may find applications in different fields, such as high-resolution spatial filters, ultra-diffractive imaging systems, high-capacity optical memories, enhanced light throughput tips for near-field scanning optical microscopes, etc. © 2011 by World Scientific Publishing Co. Pte. Ltd. All rights reserved.

A uniaxial chiral metamaterial is constructed by double-layered four "U" split ring resonators mutually twisted by 90 degrees. It shows a giant optical activity and circular dichroism. The retrieval results reveal that a negative refractive index is realized for circularly polarized waves due to the large chirality. The experimental results are in good agreement with the numerical results., Comment: 4 pages, 4 figures, Published as cover on APL

Cataloged from PDF version of article. We designed a low-loss double-negative composite metamaterial that operates at the millimeter-wave regime. A negative passband with a peak transmission value of –2.7 dB was obtained experimentally at 100 GHz. We performed transmissionbased qualitative effective medium theory analysis numerically and experimentally to prove the double-negative nature of the metamaterial. These results were supported by the standard retrieval analysis method and the study was extended by reporting the fractional bandwidth and loss of the metamaterial as the number of layers in the propagation direction increased. We numerically calculated 2-D field map and experimentally confirmed far-field radiation response of horn antenna and metamaterial lens composite. Finally, we demonstrated that the effective index of the metamaterial was negative by performing far-field angular scanning measurements for a metamaterial prism. We simulated the prism by using the Drude–Lorentz model and obtained the scattered field map in two dimensions at millimeter-wavelengths.

Cataloged from PDF version of article. We designed, implemented, and experimentally characterized electrically thin microwave absorbers by using the metamaterial concept. The absorbers consist of (i) a metal back plate and an artificial magnetic material layer; (ii) metamaterial back plate and a resistive sheet layer. We investigated absorber performance in terms of absorbance, fractional bandwidth, and electrical thickness, all of which depend on the dimensions of the metamaterial unit cell and the distance between the back plate and metamaterial layer. As a proof of concept, we demonstrated a lambda/4.7 thick absorber of type I, with a 99.8% absorption peak along with a 8% fractional bandwidth. We have shown that as the electrical size of the metamaterial unit cell decreases, the absorber electrical thickness can further be reduced. We investigated this concept by using two different magnetic metamaterial inclusions: the split-ring resonator (SRR) and multiple SSR (MSRR). We have also demonstrated experimentally a lambda/4.7 and a lambda/4.2 thick absorbers of type II, based on SRR and MSRR magnetic metamaterial back plates, respectively. The absorption peak of the SRR layout is 97.4%, while for the MSRR one the absorption peak is 98.4%. The 10 dB bandwidths were 9.9% and 9.6% for the SRR and MSRR cases, respectively. (C) 2010 American Institute of Physics.

Conference name: 2009 International Workshop Terahertz and Mid Infrared Radiation: Basic Research and Practical Applications Date of Conference: 3-6 November 2009 We review two metamaterial configurations, which are operating at the millimeter-wave scale, in terms of design, fabrication, and characterization. We observed both numerically and experimentally at around 100 GHz a narrow frequency band for which the metamaterial was low loss and had a negative index of refraction. We investigated flat and wedge shaped samples to support our characterization results. We analyzed the transmission band with respect to number of layers at the propagation direction and commented on the bulk nature of these metamaterials. Oblique response of the planar sample was also included in this study. Finally, we demonstrate a device, which yields a rather small angular width at the far field radiation pattern, and composed of a horn antenna and flat metamaterial slabs at the propagation direction. ©2009 IEEE.

Cataloged from PDF version of article. We experimentally studied the transmission response of a one-dimensional rectangle-prism-shaped metamaterial slab for oblique incidence angles. The electrical size of the split-ring resonators was 1 order of magnitude smaller than the operation wavelength similar to 8.5 cm. We demonstrated that the left-handed transmission peak preserved up to an angle of incidence 45 degrees. The angular measurements were performed with respect to two lateral directions. The confirmed insensitivity of split-ring-resonator-based metamaterials to the angle of incidence makes them a good candidate for superlens applications. (C) 2009 Optical Society of America

Periodically arranged metallic resonators can produce a negative permeability medium. However, the resonant response weakens at extreme regimes under certain conditions, which is the major problem of obtaining a negative index in the visible regime. We report that by decreasing the operation temperature, the metal conductivity can be increased, enhanced negative permeability can be obtained and the operation range of the negative permeability media, and thereby the negative index media, can be extended. We doubled the resonant strength of a typical resonator operating at microwave frequencies by decreasing its temperature to 150 K. The results are promising for the demonstration of negative index media in the visible regime.

An electromagnetic nondiffractive Bessel-like beam from a subwavelength aperture is generated by placing a metallic circular gratinglike structure in front of the aperture. When the incident wave is linearly polarized, the beam is axially asymmetric. The beam possesses fluctuating, but approximately uniform, intensity distribution along its longitudinal axis. The full width at half maximum of the beam remains less than two wavelengths over nearly ten wavelengths. Our experimental results are in good agreement with the simulation results and analytical results. © 2009 The American Physical Society.

Date of Conference: 27-31 Oct. 2008 Conference name: 38th European Microwave Conference, 2008 This paper is focussed on the miniaturization and characterization of semi-lumped resonators, of interest for the synthesis of metamaterial-based structures such as metamaterial transmission lines, frequency selective surfaces, absorbers, and radiating elements, among others. The particles consist on metallic patterns etched on a dielectric and are inspired on the split ring resonator, SRR (that is, the formerly resonant particle used for the synthesis of left handed metamaterials). The different strategies for miniaturization are discussed and examples are given. It is shown that by using two metallic levels connected through vias it is possible to achieve very small electrical size for the particles (namely, below λ/100, where λ is the wavelength in the considered substrate at resonance). A method to determine the electrical parameters of the resonators in metamaterial transmission line configurations is also presented, and the possibility to determine the characteristics of the isolated particles is discussed. Finally, examples of application of this technique are presented. This work is of interest for the synthesis of effective media metamaterials based on resonant elements. © 2008 EuMA.

We numerically and experimentally investigate a fishnet metamaterial operating at around 100 GHz. Qualitative effective medium theory and standard retrieval characterization methods are performed to demonstrate the double negative nature of the fishnet structure. This study is extended to include the effects of a finite number of unit cells at each layer and the number of layers in the propagation direction. Finally, we study the response of the metamaterial layer when the metamaterial plane normal and the propagation vector are not parallel.

Cataloged from PDF version of article. We studied electrically small resonant antennas composed of split ring resonators (SRR) and monopoles. The antennas considered have the same ring radius, but slightly different geometry. The resonance frequency depends on the geometry of the SRRs. Two SRR antennas are designed. The first one, which operates at 3.62 GHz, is demonstrated theoretically and experimentally. The size of this antenna is 0.095 lambda(0)x0.100 lambda(0) and is low profile at the other dimension. The gain and directivity of the antenna was 2.38 and 5.46, respectively. The corresponding efficiency was 43.6%. The estimated radiation Q (rad Q=23.03) was much larger than the minimum radiation Q (min Q=1.78). The second one is a rather small SRR antenna in which the capacitance between the rings is increased. The size is reduced to 0.074 lambda(0)x0.079 lambda(0). This structure is called serrated SRR (SSRR). Both antennas have similar far-field patterns but the efficiency of the SSRR antenna is less. (c) 2007 American Institute of Physics.

In this paper, we derive quasi-static equivalent-circuit models for the analysis and design of different types of artificial magnetic resonators i.e., the multiple split-ring resonator, spiral resonator, and labyrinth resonator which represent popular inclusions to synthesize artificial materials and metamaterials with anomalous values of the permeability in the microwave and millimeter-wave frequency ranges. The proposed models, derived in terms of $RLC$ equivalent circuits, represent an extension of the models presented in a recent publication. In particular, the extended models take into account the presence of a dielectric substrate hosting the metallic inclusions and the losses due to the finite conductivity of the conductors and the finite resistivity of the dielectrics. Exploiting these circuit models, it is possible to accurately predict not only the resonant frequency of the individual inclusions, but also their quality factor and the relative permeability of metamaterial samples made by given arrangements of such inclusions. Finally, the three models have been tested against full-wave simulations and measurements, showing a good accuracy. This result opens the door to a quick and accurate design of the artificial magnetic inclusions to fabricate real-life metamaterial samples with anomalous values of the permeability. © 2006 IEEE.

Cataloged from PDF version of article. Experimental and numerical studies of mu-negative (MNG) materials such as multisplit ring resonators (MSRRs) and spiral resonators (SRs) are presented. The resonance frequency of the structures is determined by the transmission measurements and minimum electrical size of lambda(0)/17 for the MSRRs and of lambda(0)/82 for the SRs observed. These MNG materials can be easily produced by the well developed printed circuit board and optical lithography techniques. They are promising elements for the development of high resolution metamaterial lenses and electrically small antennas. (c) 2007 American Institute of Physics.

We report the spectral refraction analysis and focusing properties of a two-dimensional, dielectric photoniccrystal (PC) slab in freespace. A transverse electric polarized upper band of the crystal is used. The measuredrefraction spectra indicates that a highly isotropic negative index of refraction is present in the measuredfrequency range of the band. We demonstrate experimentally and numerically the focusing of the field emittedfrom an omnidirectional source placed in front of the crystal. Both the source and the focus pattern are awayfrom the PC interfaces of the order of several wavelengths. The focus pattern mimics the arbitrary lateral andlongitudinal shifts of the source, which is a manifestation of true flat lens behavior.DOI: 10.1103/PhysRevB.70.205125 PACS number(s): 42.25.2p, 78.20.Ci, 42.79.BhI. INTRODUCTION

Cataloged from PDF version of article. We designed, fabricated, and experimentally characterized thin absorbers utilizing both electrical and magnetic impedance matching at the near-infrared regime. The absorbers consist of four main layers: a metal back plate, dielectric spacer, and two artificial layers. One of the artificial layers provides electrical resonance and the other one provides magnetic resonance yielding a polarization independent broadband perfect absorption. The structure response remains similar for the wide angle of incidence due to the sub-wavelength unit cell size of the constituting artificial layers. The design is useful for applications such as thermal photovoltaics, sensors, and camouflage. (C)2011 Optical Society of America

Cataloged from PDF version of article. We studied the transmission characteristics of a one-dimensional metamaterial slab operating at the millimeter-wave regime. The double-negative nature was proven by using a normal incidence transmission study. A split-ring resonator based metamaterial flat lens with five layers at the propagation direction was constructed and illuminated with oblique incidence. From the scanning experiments, the shifting of the beam to the negative side was observed. The experimental results are in agreement with the Drude-Lorentz model based simulations. Two-dimensional field maps that were obtained from these simulations demonstrated negative refraction, negative phase velocity, and the reflected beam properties at 99 GHz. (C) 2009 Optical Society of America

Purpose – Metamaterial unit cells composed of deep subwavelength resonators brought up new aspects to the antenna miniaturization problem. The paper experimentally demonstrates a metamaterial-inspired miniaturization method for circular patch antennas. In the proposed layouts, the space between the patch and the ground plane is filled with a proper metamaterial composed of either multiple split-ring or spiral resonators (SRs). The authors have manufactured two different patch antennas, achieving an electrical size of λ/3.69 and λ/8.26, respectively. The paper aims to discuss these issues. Design/methodology/approach – The operation of such a radiative component has been predicted by using a simple theoretical formulation based on the cavity model. The experimental characterization of the antenna has been performed by using a HP8510C vector network analyzer, standard horn antennas, automated rotary stages, coaxial cables with 50 Ω characteristic impedance and absorbers. Before the characterization measurements we performed a full two-port calibration. Findings – Electrically small circular patch antennas loaded with single layer metamaterials experimentally demonstrated to acceptable figures of merit for applications. The proposed miniaturization technique is potentially promising for antenna applications and the results presented in the paper constitute a relevant proof for the usefulness of the metamaterial concepts in antenna miniaturization problems. Originality/value – Rigorous experimental characterization of several meta material loaded antennas and proof of principle results were provided.

We introduce electrically connected Fano-resonant metasurfaces consisting of a periodic array of antennas connected to wires. Possibility of the direct interaction among the antennas by the charge transfer allows for robust high quality Fano resonances.

Precise information about the structure of protein monolayers (thickness, bond orientation, dipole strength) can be obtained using difference-reflectivity spectroscopy of functionalized Fano-resonant asymmetric metamaterials. Experimental results for peptide, single-protein, and two-protein monolayers will be presented. (C) 2010 Optical Society of America