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Author

Joan Garcia-Garcia

Other affiliations: University of Barcelona
Bio: Joan Garcia-Garcia is an academic researcher from Autonomous University of Barcelona. The author has contributed to research in topics: Resonator & Microstrip. The author has an hindex of 26, co-authored 90 publications receiving 4394 citations. Previous affiliations of Joan Garcia-Garcia include University of Barcelona.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a new approach for the development of planar metamaterial structures is developed, and analytical equivalent circuit models are proposed for isolated and coupled split-ring resonators/CSRRs coupled to planar transmission lines.
Abstract: In this paper, a new approach for the development of planar metamaterial structures is developed. For this purpose, split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) coupled to planar transmission lines are investigated. The electromagnetic behavior of these elements, as well as their coupling to the host transmission line, are studied, and analytical equivalent-circuit models are proposed for the isolated and coupled SRRs/CSRRs. From these models, the stopband/passband characteristics of the analyzed SRR/CSRR loaded transmission lines are derived. It is shown that, in the long wavelength limit, these stopbands/passbands can be interpreted as due to the presence of negative/positive values for the effective /spl epsiv/ and /spl mu/ of the line. The proposed analysis is of interest in the design of compact microwave devices based on the metamaterial concept.

1,405 citations

Journal ArticleDOI
TL;DR: In this paper, a new methodology for the design of compact planar filters in microstrip technology is proposed, based on cascading filter stages consisting of the combination of complementary split-ring resonators (CSRRs), series capacitive gaps, and grounded stubs.
Abstract: In this paper, a new methodology for the design of compact planar filters in microstrip technology is proposed. This is based on cascading filter stages consisting of the combination of complementary split-ring resonators (CSRRs), recently proposed by the authors, series capacitive gaps, and grounded stubs. By this means, we achieve the necessary flexibility to simultaneously obtain quite symmetric frequency responses, controllable bandwidths, and compact dimensions. Two prototype device bandpass filters are provided to illustrate the potentiality of the proposed approach. In the first prototype, the structure is periodic (i.e., composed of identical cells) and behaves as a left-handed transmission line with controllable bandwidth. In the second prototype device, periodicity is sacrificed with an eye toward the synthesis of a standard (Chebyshev) approximation. The measured frequency responses point out low insertion losses in the passband, as well as high-frequency selectivity with small dimensions. As compared to conventional parallel coupled line filters, reduction of device length by a factor of 2.4 is demonstrated. This is the first time that planar filters with controllable bandwidth based on CSRRs are achieved. These structures can be of interest in those applications where miniaturization and compatibility with planar circuit technology are key issues

303 citations

Journal ArticleDOI
TL;DR: In this paper, a method to obtain the electrical characteristics of complementary split ring resonators (CSRRs) coupled to planar transmission lines is presented, which is of actual interest for the design of microwave circuits and metamaterials based on these complementary resonant particles.
Abstract: In this letter, a method to obtain the electrical characteristics of complementary split ring resonators (CSRRs) coupled to planar transmission lines is presented. CSRRs have been recently proposed by some of the authors as new constitutive elements for the synthesis of metamaterials with negative effective permittivity, and they have been applied to the fabrication of metamaterial-based circuits in planar technology. The method provides the electrical characteristics of CSRRs (including the intrinsic resonant frequency and the unloaded Q-factor), as well as the coupling capacitance between line and CSRRs, and the parameters of the host line. Parameter extraction from the proposed method is applied to two different structures corresponding to the basic cells of left handed (LH) and negative permittivity lines. The method is of actual interest for the design of microwave circuits and metamaterials based on these complementary resonant particles

242 citations

Journal ArticleDOI
13 Jun 2005
TL;DR: In this article, the authors demonstrate the potential of sub-wavelength resonators, namely, split-ring resonators and complementary split ring resonators to suppress undesired spurious bands in microwave filters, a key aspect to improve their rejection bandwidths.
Abstract: The main aim of this paper is to demonstrate the potentiality of sub-wavelength resonators, namely, split-ring resonators, complementary split-ring resonators, and related structures to the suppression of undesired spurious bands in microwave filters, a key aspect to improve their rejection bandwidths. The main relevant characteristics of the cited resonators are their dimensions (which can be much smaller than signal wavelength at resonance) and their high-Q factor. This allows us to design stopband structures with significant rejection levels, few stages, and small dimensions, which can be integrated within the filter active region. By this means, no extra area is added to the device, while the passband of interest is virtually unaltered. A wide variety of bandpass filters, implemented in both coplanar-waveguide and microstrip technologies, have been designed and fabricated by the authors. The characterization of these devices points out the efficiency of the proposed approach to improve filter responses with harmonic rejection levels near 40 dB in some cases. It is also important to highlight that the conventional design methodology for the filters holds. For certain configurations, the presence of the resonators slightly lowers the phase velocity at the frequencies of interest with the added advantage of some level of reduction in device dimensions.

217 citations

Journal ArticleDOI
TL;DR: In this paper, split ring resonators (SRRs) are used to suppress spurious passband suppression in microstrip coupled line band pass filters by means of split-ring resonators.
Abstract: In this letter, spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators (SRRs) is demonstrated for the first time. By etching SRRs in the upper substrate side, in close proximity to conductor strip, strong magnetic coupling between line and rings arises at the resonant frequency of SRRs. This inhibits signal propagation in the vicinity of that frequency, allowing the rejection of undesired passbands by properly tuning SRRs. To test this novel technique, we have designed and fabricated two different SSRs-based filters. In one case, the rings have been designed to suppress only the first spurious band, and SRRs have been etched at both sides of the 50-/spl Omega/ access lines. For the other prototype, SRRs have been etched on the active device region (i.e., surrounding the parallel coupled lines) and have been tuned to eliminate the first and second undesired bands. The measured frequency responses for these devices confirm the efficiency of this technique to suppress frequency parasitics, with rejection levels near 40 dBs, leaving the passband unaltered. Since SRRs are small particles (with sub-wavelength dimensions at the resonant frequency), this approach does not add extra area to the final layouts. Moreover, the conventional design methodology of the filters holds.

198 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: This Review summarizes research on photonic, terahertz and microwave electromagnetic metamaterials and metadevices with functionalities attained through the exploitation of phase-change media, semiconductors, graphene, carbon nanotubes and liquid crystals.
Abstract: Metamaterials, artificial electromagnetic media that are structured on the subwavelength scale, were initially suggested for the negative-index 'superlens'. Later metamaterials became a paradigm for engineering electromagnetic space and controlling propagation of waves: the field of transformation optics was born. The research agenda is now shifting towards achieving tunable, switchable, nonlinear and sensing functionalities. It is therefore timely to discuss the emerging field of metadevices where we define the devices as having unique and useful functionalities that are realized by structuring of functional matter on the subwavelength scale. In this Review we summarize research on photonic, terahertz and microwave electromagnetic metamaterials and metadevices with functionalities attained through the exploitation of phase-change media, semiconductors, graphene, carbon nanotubes and liquid crystals. The Review also encompasses microelectromechanical metadevices, metadevices engaging the nonlinear and quantum response of superconductors, electrostatic and optomechanical forces and nonlinear metadevices incorporating lumped nonlinear components.

1,741 citations

Journal ArticleDOI
TL;DR: In this paper, a new approach for the development of planar metamaterial structures is developed, and analytical equivalent circuit models are proposed for isolated and coupled split-ring resonators/CSRRs coupled to planar transmission lines.
Abstract: In this paper, a new approach for the development of planar metamaterial structures is developed. For this purpose, split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) coupled to planar transmission lines are investigated. The electromagnetic behavior of these elements, as well as their coupling to the host transmission line, are studied, and analytical equivalent-circuit models are proposed for the isolated and coupled SRRs/CSRRs. From these models, the stopband/passband characteristics of the analyzed SRR/CSRR loaded transmission lines are derived. It is shown that, in the long wavelength limit, these stopbands/passbands can be interpreted as due to the presence of negative/positive values for the effective /spl epsiv/ and /spl mu/ of the line. The proposed analysis is of interest in the design of compact microwave devices based on the metamaterial concept.

1,405 citations

Journal ArticleDOI
TL;DR: In this article, the basic physics and applications of planar metamaterials, often called metasurfaces, which are composed of optically thin and densely packed planar arrays of resonant or nearly resonant subwavelength elements, are reviewed.

1,047 citations

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate frequency-agile terahertz metamaterials operating in the far-infrared by incorporating semiconductors in critical regions of metallic split-ring resonators.
Abstract: Metamaterials exhibit numerous novel effects1,2,3,4,5 and operate over a large portion of the electromagnetic spectrum6,7,8,9,10. Metamaterial devices based on these effects include gradient-index lenses11,12, modulators for terahertz radiation13,14,15 and compact waveguides16. The resonant nature of metamaterials results in frequency dispersion and narrow bandwidth operation where the centre frequency is fixed by the geometry and dimensions of the elements comprising the metamaterial composite. The creation of frequency-agile metamaterials would extend the spectral range over which devices function and, further, enable the manufacture of new devices such as dynamically tunable notch filters. Here, we demonstrate such frequency-agile metamaterials operating in the far-infrared by incorporating semiconductors in critical regions of metallic split-ring resonators. For this first-generation device, external optical control results in tuning of the metamaterial resonance frequency by ∼20%. Our approach is integrable with current semiconductor technologies and can be implemented in other regions of the electromagnetic spectrum. Metamaterials that possess frequency tunability enable new device functions. By external optical control through the incorporation of semiconductors in metallic split-ring resonators, the researchers provide an elegant solution to frequency-agile terahertz metamaterials.

787 citations

Journal ArticleDOI
27 Feb 2010-Science
TL;DR: In this paper, the authors demonstrate a form of memory capacitance which interfaces metamaterials with a class of devices known collectively as memory devices, and demonstrate electrically-controlled persistent frequency tuning of a metammaterial, allowing lasting modification of its response using a transient stimulus.
Abstract: The resonant elements that grant metamaterials their unique properties have the fundamental limitation of restricting their useable frequency bandwidth The development of frequency-agile metamaterials has helped to alleviate these bandwidth restrictions by allowing real-time tuning of the metamaterial frequency response We demonstrate electrically-controlled persistent frequency tuning of a metamaterial, allowing lasting modification of its response using a transient stimulus This work demonstrates a form of memory capacitance which interfaces metamaterials with a class of devices known collectively as memory devices

739 citations