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Proceedings ArticleDOI

Metamaterial-inspired antennas for telecommunication applications

26 Mar 2012-pp 2739-2740
TL;DR: In this paper, the design of a new switched beam antenna based on metamaterial-inspired printed radiators is presented, which is placed vertically at the four corners of a grounded squared board and properly excited by the means of a dedicated switching network.
Abstract: In this contribution, we propose the design of a new switched beam antenna, based on metamaterial-inspired printed radiators The radiators (ie electrically short monopoles) are placed vertically at the four corners of a grounded squared board and properly excited by the means of a dedicated switching network The goal is to design an improved gain vertically polarized antenna for compact wireless modules in the 1600–2700 MHz frequency band, for use in areas with reduced signal coverage and/or high interference levels The numerical design of the antenna as well as its actual implementation (fabrication and testing) are presented and discussed
Citations
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Journal ArticleDOI
TL;DR: In this article , an extensive literature survey is accomplished to get conception about metamaterial-inspired patch antennas and the results of different metammaterial-inspired antennas such as bandwidth, gain, return loss, and resonant frequency have been also represented in this paper.
Abstract: Nowadays, the demand for low-cost, compact, and interference rejected antennas with ultrawideband capability has been increased. Metamaterial-inspired loaded structures have capability of providing exceptional solutions for narrow range wireless communication and low consuming power while transmitting and receiving the signal. It is a difficult task to construct ideal metamaterial-inspired antennas with a variety of features such as extremely large bandwidth, notching out undesirable bands, and frequency. Metamaterial-inspired structures such as SRR and CSRR, and triangle-shaped TCSRR are most commonly used structures to achieve optimized characteristics in ultrawideband antennas. In this paper, an extensive literature survey is accomplished to get conception about metamaterial-inspired patch antennas. This review paper elucidates variants of metamaterial-inspired structures/resonators utilized in order to acquire sundry applications such as WiMAX, WLAN, satellite communication, and radar. Various researchers have used different methodology to design, stimulate, and analyze the metamaterial-inspired structure loaded antennas. Also, the results of different metamaterial-inspired antennas such as bandwidth, gain, return loss, and resonant frequency have been also represented in this paper. This manuscript also gives brief introduction about the metamaterial, its types, and then its application in microstrip patch antenna over the last decade. This manuscript throws light over the various studies conducted in the field of metamaterial-inspired antenna in the past. It has been seen that with the inclusion of metamaterial in conventional antenna, various characteristics such as impedance bandwidth, reflection coefficient, gain, and directivity have been improved. Also, frequency rejection of narrow bands which exits in ultrawideband frequency range can be done by embedding metamaterial-inspired structures such as SRR and CSRR.

13 citations

Proceedings ArticleDOI
01 Oct 2013
TL;DR: In this article, the delay time is composed of the dwell time in the resonant tunneling region and the transit time in collector depletion region, and a fundamental oscillation up to 1.31 THz with the output power of 10 microwatts was obtained at room temperature.
Abstract: Our recent results of THz oscillators using GaInAs/AlAs resonant tunneling diodes (RTDs) were reported. For high frequency oscillation, the delay time of electrons was reduced. The delay time is composed of the dwell time in the resonant tunneling region and the transit time in the collector depletion region. The dwell time was reduced by a narrow quantum well, and a fundamental oscillation up to 1.31 THz with the output power of 10 microwatts was obtained at room temperature. The dependence of the oscillation frequency on thickness of collector spacer layer was investigated to obtain the optimum spacer thickness for short transit time and small capacitance, and a fundamental oscillation at 1.37 THz with 10 microwatts was achieved. A higher frequency is further possible with the structure optimization. For high output power, the offset slot antenna and coherent power combining were demonstrated, and 610 microwatts at 620 GHz was obtained with a two-element offset-antenna array. The spectral linewidth less than 10 MHz and a frequency change with bias voltage were also obtained. A preliminary experiment on wireless data transmission was demonstrated with the direct intensity modulation of RTD oscillator with bias voltage, and a transmission rate of 3 Gbps with the bit error rate of 3E-5 was obtained at 540 GHz. The bit rate is limited at present by the external capacitance around RTD.

12 citations

Journal ArticleDOI
TL;DR: In this article, the design of innovative radiating systems based on the metamaterial technology for GNSS (Global Navigation Satellite System) applications in radio frequency (RF) interference conditions is proposed.
Abstract: The design of innovative radiating systems based on the metamaterial technology for GNSS (Global Navigation Satellite System) applications in radio frequency (RF) interference conditions is proposed. To this aim, firstly two typical adaptive array techniques (i.e., nulling and beam-forming) are discussed and tradeed off. Secondly, FRPA (Fixed Radiation Pattern Antenna) and CRPA (Controlled Radiation Pattern Antenna) phased array configurations of miniaturized patch antennas are studied by means of electromagnetic commercial tools and phased array optimization algorithms. This process leads to the identification of a phased array design. Benefits and drawbacks for GNSS applications are highlighted. Finally, the design of the phased array is applied to a GNSS user receiver in a navigation realistic environment. Simulation results are obtained in a realistic scenario for railway applications, comprising of a GNSS satellite constellation, a GNSS user receiver (i.e., on-board train equipment) running along a track in Western Australia, and a constellation of interfering satellites. Navigation service performances (i.e., user location accuracy and service availability) are computed taking into account the adaptive array radiation pattern in two different modes (i.e., FRPA or CRPA) and band-limited white noise interference.

3 citations


Cites background from "Metamaterial-inspired antennas for ..."

  • ..., the array) can be drastically reduced [13, 14]....

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Dissertation
01 Jan 2019
TL;DR: This paper aims to provide a chronology of the events leading up to and including the publication of this work and some of the key events that led to its publication.
Abstract: ..................................................................................................................................... 2 Acknowledgements .................................................................................................................... 3 Table of

2 citations


Cites background from "Metamaterial-inspired antennas for ..."

  • ...There are quite a numbers of academic journals wrote on the subject of using phased array for pattern reconfigurable antennas, which are fed by equal amplitude and proper phase signals [35][36][37]....

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  • ...7 The arrangement of frequency and radiation pattern reconfigurable antenna (a)circular array antenna and (b)the whole antenna system[35]....

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Proceedings ArticleDOI
01 Oct 2013
TL;DR: Concern about GPS (Global Positioning System) vulnerability has received a great deal of attention recently and signal interference threatens all the GNSS receivers, military and civilian.
Abstract: Concern about GPS (Global Positioning System) vulnerability has received a great deal of attention recently [1,3]. GNSS receivers are highly susceptible to interference caused by jamming and spoofing. Historically, signal jamming and the design against have been primarily considered as a military problem. Now, signal interference threatens all the GNSS receivers, military and civilian.
References
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BookDOI
11 Nov 2005
TL;DR: In this paper, the authors define Metamaterials (MTMs) and Left-Handed (LH) MTMs as a class of two-dimensional MTMs.
Abstract: Preface. Acknowledgments. Acronyms. 1 Introduction. 1.1 Definition of Metamaterials (MTMs) and Left-Handed (LH) MTMs. 1.2 Theoretical Speculation by Viktor Veselago. 1.3 Experimental Demonstration of Left-Handedness. 1.4 Further Numerical and Experimental Confirmations. 1.5 "Conventional" Backward Waves and Novelty of LH MTMs. 1.6 Terminology. 1.7 Transmission Line (TL) Approach. 1.8 Composite Right/Left-Handed (CRLH) MTMs. 1.9 MTMs and Photonic Band-Gap (PBG) Structures. 1.10 Historical "Germs" of MTMs. References. 2 Fundamentals of LH MTMs. 2.1 Left-Handedness from Maxwell's Equations. 2.2 Entropy Conditions in Dispersive Media. 2.3 Boundary Conditions. 2.4 Reversal of Doppler Effect. 2.5 Reversal of Vavilov- Cerenkov Radiation. 2.6 Reversal of Snell's Law: Negative Refraction. 2.7 Focusing by a "Flat LH Lens". 2.8 Fresnel Coefficients. 2.9 Reversal of Goos-H anchen Effect. 2.10 Reversal of Convergence and Divergence in Convex and Concave Lenses. 2.11 Subwavelength Diffraction. References. 3 TLTheoryofMTMs. 3.1 Ideal Homogeneous CRLH TLs. 3.1.1 Fundamental TL Characteristics. 3.1.2 Equivalent MTM Constitutive Parameters. 3.1.3 Balanced and Unbalanced Resonances. 3.1.4 Lossy Case. 3.2 LC Network Implementation. 3.2.1 Principle. 3.2.2 Difference with Conventional Filters. 3.2.3 Transmission Matrix Analysis. 3.2.4 Input Impedance. 3.2.5 Cutoff Frequencies. 3.2.6 Analytical Dispersion Relation. 3.2.7 Bloch Impedance. 3.2.8 Effect of Finite Size in the Presence of Imperfect Matching. 3.3 Real Distributed 1D CRLH Structures. 3.3.1 General Design Guidelines. 3.3.2 Microstrip Implementation. 3.3.3 Parameters Extraction. 3.4 Experimental Transmission Characteristics. 3.5 Conversion from Transmission Line to Constitutive Parameters. References. 4 Two-Dimensional MTMs. 4.1 Eigenvalue Problem. 4.1.1 General Matrix System. 4.1.2 CRLH Particularization. 4.1.3 Lattice Choice, Symmetry Points, Brillouin Zone, and 2D Dispersion Representations. 4.2 Driven Problem by the Transmission Matrix Method (TMM). 4.2.1 Principle of the TMM. 4.2.2 Scattering Parameters. 4.2.3 Voltage and Current Distributions. 4.2.4 Interest and Limitations of the TMM. 4.3 Transmission Line Matrix (TLM) Modeling Method. 4.3.1 TLM Modeling of the Unloaded TL Host Network. 4.3.2 TLM Modeling of the Loaded TL Host Network (CRLH). 4.3.3 Relationship between Material Properties and the TLM Model Parameters. 4.3.4 Suitability of the TLM Approach for MTMs. 4.4 Negative Refractive Index (NRI) Effects. 4.4.1 Negative Phase Velocity. 4.4.2 Negative Refraction. 4.4.3 Negative Focusing. 4.4.4 RH-LH Interface Surface Plasmons. 4.4.5 Reflectors with Unusual Properties. 4.5 Distributed 2D Structures. 4.5.1 Description of Possible Structures. 4.5.2 Dispersion and Propagation Characteristics. 4.5.3 Parameter Extraction. 4.5.4 Distributed Implementation of the NRI Slab. References. 5 Guided-Wave Applications. 5.1 Dual-Band Components. 5.1.1 Dual-Band Property of CRLH TLs. 5.1.2 Quarter-Wavelength TL and Stubs. 5.1.3 Passive Component Examples: Quadrature Hybrid and Wilkinson Power Divider. 5.1.3.1 Quadrature Hybrid. 5.1.3.2 Wilkinson Power Divider. 5.1.4 Nonlinear Component Example: Quadrature Subharmonically Pumped Mixer. 5.2 Enhanced-Bandwidth Components. 5.2.1 Principle of Bandwidth Enhancement. 5.2.2 Rat-Race Coupler Example. 5.3 Super-compact Multilayer "Vertical" TL. 5.3.1 "Vertical" TL Architecture. 5.3.2 TL Performances. 5.3.3 Diplexer Example. 5.4 Tight Edge-Coupled Coupled-Line Couplers (CLCs). 5.4.1 Generalities on Coupled-Line Couplers. 5.4.1.1 TEM and Quasi-TEM Symmetric Coupled-Line Structures with Small Interspacing: Impedance Coupling (IC). 5.4.1.2 Non-TEM Symmetric Coupled-Line Structures with Relatively Large Spacing: Phase Coupling (PC). 5.4.1.3 Summary on Symmetric Coupled-Line Structures. 5.4.1.4 Asymmetric Coupled-Line Structures. 5.4.1.5 Advantages of MTM Couplers. 5.4.2 Symmetric Impedance Coupler. 5.4.3 Asymmetric Phase Coupler. 5.5 Negative and Zeroth-Order Resonator. 5.5.1 Principle. 5.5.2 LC Network Implementation. 5.5.3 Zeroth-Order Resonator Characteristics. 5.5.4 Circuit Theory Verification. 5.5.5 Microstrip Realization. References. 6 Radiated-Wave Applications. 6.1 Fundamental Aspects of Leaky-Wave Structures. 6.1.1 Principle of Leakage Radiation. 6.1.2 Uniform and Periodic Leaky-Wave Structures. 6.1.2.1 Uniform LW Structures. 6.1.2.2 Periodic LW Structures. 6.1.3 Metamaterial Leaky-Wave Structures. 6.2 Backfire-to-Endfire (BE) Leaky-Wave (LW) Antenna. 6.3 Electronically Scanned BE LW Antenna. 6.3.1 Electronic Scanning Principle. 6.3.2 Electronic Beamwidth Control Principle. 6.3.3 Analysis of the Structure and Results. 6.4 Reflecto-Directive Systems. 6.4.1 Passive Retro-Directive Reflector. 6.4.2 Arbitrary-Angle Frequency Tuned Reflector. 6.4.3 Arbitrary-Angle Electronically Tuned Reflector. 6.5 Two-Dimensional Structures. 6.5.1 Two-Dimensional LW Radiation. 6.5.2 Conical-Beam Antenna. 6.5.3 Full-Space Scanning Antenna. 6.6 Zeroth Order Resonating Antenna. 6.7 Dual-Band CRLH-TL Resonating Ring Antenna. 6.8 Focusing Radiative "Meta-Interfaces". 6.8.1 Heterodyne Phased Array. 6.8.2 Nonuniform Leaky-Wave Radiator. References. 7 The Future of MTMs. 7.1 "Real-Artificial" Materials: the Challenge of Homogenization. 7.2 Quasi-Optical NRI Lenses and Devices. 7.3 Three-Dimensional Isotropic LH MTMs. 7.4 Optical MTMs. 7.5 "Magnetless" Magnetic MTMs. 7.6 Terahertz Magnetic MTMs. 7.7 Surface Plasmonic MTMs. 7.8 Antenna Radomes and Frequency Selective Surfaces. 7.9 Nonlinear MTMs. 7.10 Active MTMs. 7.11 Other Topics of Interest. References. Index.

2,750 citations

Book
01 Jan 2006
TL;DR: In this paper, the authors present a three-dimensional VOLUMEETRIC DNG METAMATERIALs, which are used to generate wave parameters in DNG Media.
Abstract: Preface. Contributors. PART I: DOUBLE-NEGATIVE (DNG) METAMATERIALS. SECTION I: THREE-DIMENSIONAL VOLUMETRIC DNG METAMATERIALS. CHAPTER 1: INTRODUCTION, HISTORY, AND SELECTED TOPICS IN FUNDAMENTAL THEORIES OF METAMATERIALS (Richard W. Ziolkowski and Nader Engheta). 1.1 Introduction. 1.2 Wave Parameters in DNG Media. 1.3 FDTD Simulations of DNG Media. 1.4 Causality in DNG Media. 1.5 Scattering from a DNG Slab. 1.6 Backward Waves. 1.7 Negative Refraction. 1.8 Phase Compensation with a DNG Medium. 1.9 Dispersion Compensation in a Transmission Line Using a DNG Medium. 1.10 Subwavelength Focusing with a DNG Medium. 1.11 Metamaterials with a Zero Index of Refraction. 1.12 Summary. References. CHAPTER 2: FUNDAMENTALS OF WAVEGUIDE AND ANTENNA APPLICATIONS INVOLVING DNG AND SNG METAMATERIALS (Nader Engheta, Andrea Alu, Richard W. Ziolkowski, and Aycan Erentok). 2.1 Introduction. 2.2 Subwavelength Cavities and Waveguides. 2.3 Subwavelength Cylindrical and Spherical Core-Shell Systems. 2.4 ENG-MNG and DPS-DNG Matched Metamaterial Pairs for Resonant Enhancements of Source-Generated Fields. 2.5 Efficient, Electrically Small Dipole Antennas: DNG Nested Shells. 2.6 Efficient, Electrically Small Dipole Antennas: ENG Nested Shells-Analysis. 2.7 Efficient, Electrically Small Dipole Antennas: HFSS Simulations of Dipole-ENG Shell Systems. 2.8 Metamaterial Realization of an Artificial Magnetic Conductor for Antenna Applications. 2.9 Zero-Index Metamaterials for Antenna Applications. 2.10 Summary. References. CHAPTER 3: WAVEGUIDE EXPERIMENTS TO CHARACTERIZE PROPERTIES OF SNG AND DNG METAMATERIALS (Silvio Hrabar). 3.1 Introduction. 3.2 Basic Types of Bulk Metamaterials with Inclusions. 3.3 Theoretical Analysis of Rectangular Waveguide Filled with General Metamaterial. 3.4 Investigation of Rectangular Waveguide Filled with 2D Isotropic ENG Metamaterial. 3.5 Investigation of Rectangular Waveguide Filled with 2D Isotropic MNG Metamaterial. 3.6 Investigation of Rectangular Waveguide Filled with 2D Uniaxial MNG Metamaterial. 3.7 Investigation of Rectangular Waveguide Filled with 2D Isotropic DNG Metamaterial. 3.8 Investigation of Subwavelength Resonator. 3.9 Conclusions. References. CHAPTER 4: REFRACTION EXPERIMENTS IN WAVEGUIDE ENVIRONMENTS (Tomasz M. Grzegorczyk, Jin Au Kong, and Ran Lixin). 4.1 Introduction. 4.2 Microscopic and Macroscopic Views of Metamaterials. 4.3 Measurement Techniques. 4.4 Conclusion. Acknowledgments. References. SECTION II: TWO-DIMENSIONAL PLANAR NEGATIVE-INDEX STRUCTURES. CHAPTER 5: ANTENNA APPLICATIONS AND SUBWAVELENGTH FOCUSING USING NEGATIVE-REFRACTIVE-INDEX TRANSMISSION LINE STRUCTURES (George V. Eleftheriades). 5.1 Introduction. 5.2 Planar Transmission Line Media with Negative Refractive Index. 5.3 Zero-Degree Phase-Shifting Lines and Applications. 5.4 Backward Leaky-Wave Antenna Radiating in Its Fundamental Spatial Harmonic. 5.5 Superresolving NRI Transmission Line Lens. 5.6 Detailed Dispersion of Planar NRI-TL Media. Acknowledgments. References. CHAPTER 6: RESONANCE CONE ANTENNAS (Keith G. Balmain and Andrea A. E. Luttgen). 6.1 Introduction. 6.2 Planar Metamaterial, Corner-Fed, Anisotropic Grid Antenna. 6.3 Resonance Cone Refraction Effects in a Low-Profile Antenna. 6.4 Conclusions. Acknowledgments. References. CHAPTER 7: MICROWAVE COUPLER AND RESONATOR APPLICATIONS OF NRI PLANAR STRUCTURES (Christophe Caloz and Tatsuo Itoh). 7.1 Introduction. 7.2 Composite Right/Left-Handed Transmission Line Metamaterials. 7.3 Metamaterial Couplers. 7.4 Metamaterial Resonators. 7.5 Conclusions. References. PART II: ELECTROMAGNETIC BANDGAP (EBG) METAMATERIALS. SECTION I: THREE-DIMENSIONAL VOLUMETRIC EBG MEDIA. CHAPTER 8: HISTORICAL PERSPECTIVE AND REVIEW OF FUNDAMENTAL PRINCIPLES IN MODELING THREE-DIMENSIONAL PERIODIC STRUCTURES WITH EMPHASIS ON VOLUMETRIC EBGs (Maria Kafesaki and Costas M. Soukoulis). 8.1 Introduction. 8.2 Theoretical and Numerical Methods. 8.3 Comparison of Different Numerical Techniques. 8.4 Conclusions. Acknowledgments. References. CHAPTER 9: FABRICATION, EXPERIMENTATION, AND APPLICATIONS OF EBG STRUCTURES (Peter de Maagt and Peter Huggard). 9.1 Introduction. 9.2 Manufacturing. 9.3 Experimental Characterization of EBG Crystals. 9.4 Current and Future Applications of EBG Systems. 9.5 Conclusions. References. CHAPTER 10: SUPERPRISM EFFECTS AND EBG ANTENNA APPLICATIONS (Boris Gralak, Stefan Enoch, and G-erard Tayeb). 10.1 Introduction. 10.2 Refractive Properties of a Piece of Photonic Crystal. 10.3 Superprism Effect. 10.4 Antenna Applications. 10.5 Conclusion. References. SECTION II: TWO-DIMENSIONAL PLANAR EBG STRUCTURES. CHAPTER 11: REVIEW OF THEORY, FABRICATION, AND APPLICATIONS OF HIGH-IMPEDANCE GROUND PLANES (Dan Sievenpiper). 11.1 Introduction. 11.2 Surface Waves. 11.3 High-Impedance Surfaces. 11.4 Surface Wave Bands. 11.5 Reflection Phase. 11.6 Bandwidth. 11.7 Design Procedure. 11.8 Antenna Applications. 11.9 Tunable Impedance Surfaces. 11.10 Reflective-Beam Steering. 11.11 Leaky-Wave Beam Steering. 11.12 Backward Bands. 11.13 Summary. References. CHAPTER 12: DEVELOPMENT OF COMPLEX ARTIFICIAL GROUND PLANES IN ANTENNA ENGINEERING (Yahya Rahmat-Samii and Fan Yang). 12.1 Introduction. 12.2 FDTD Analysis of Complex Artificial Ground Planes. 12.3 Various Complex Artificial Ground-Plane Designs. 12.4 Applications of Artificial Ground Planes in Antenna Engineering. 12.5 Summary. References. CHAPTER 13: FSS-BASED EBG SURFACES (Stefano Maci and Alessio Cucini). 13.1 Introduction. 13.2 MoM Solution. 13.3 Accessible Mode Admittance Network. 13.4 Pole-Zero Matching Method for Dispersion Analysis. 13.5 Conclusions. Acknowledgments. References. CHAPTER 14: SPACE-FILLING CURVE HIGH-IMPEDANCE GROUND PLANES (John McVay, Nader Engheta, and Ahmad Hoorfar). 14.1 Resonances of Space-Filling Curve Elements. 14.2 High-Impedance Surfaces Made of Space-Filling Curve Inclusions. 14.3 Use of Space-Filling Curve High-Impedance Surfaces in Antenna Applications. 14.4 Space-Filling Curve Elements as Inclusions in DNG Bulk Media. 14.5 Conclusions. References. Index.

1,458 citations


"Metamaterial-inspired antennas for ..." refers background in this paper

  • ...Broadband operation and reduced space occupancy are obtained by adopting metamaterial concepts, which have been recently applied to a variety of antennas and radiating systems [1]-[9]....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the effect of surrounding an electrically small dipole antenna with a shell of double negative (DNG) material has been investigated both analytically and numerically, and it is shown that a properly designed dipole-DNG shell combination increases the real power radiated by more than an order of magnitude over the corresponding free space case.
Abstract: The effect of surrounding an electrically small dipole antenna with a shell of double negative (DNG) material (/spl epsiv//sub r/<0 and /spl mu//sub r/<0) has been investigated both analytically and numerically. The problem of an infinitesimal electric dipole embedded in a homogeneous DNG medium is treated; its analytical solution shows that this electrically small antenna acts inductively rather than capacitively as it would in free space. It is then shown that a properly designed dipole-DNG shell combination increases the real power radiated by more than an order of magnitude over the corresponding free space case. The reactance of the antenna is shown to have a corresponding decrease. Analysis of the reactive power within this dipole-DNG shell system indicates that the DNG shell acts as a natural matching network for the dipole. An equivalent circuit model is introduced that confirms this explanation. Several cases are presented to illustrate these results. The difficult problem of interpreting the energy stored in this dipole-DNG shell system when the DNG medium is frequency independent and, hence, of calculating the radiation Q is discussed from several points of view.

431 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a sub-wavelength radiating antenna with magnetic inclusions that can operate even when the fabricated MNG sample is not isotropic, due to the specific polarization of the magnetic field in the MNG region.
Abstract: Recent theoretical studies have shown that circular patch antennas loaded by an inhomogeneous substrate partially filled with a mu-negative (MNG) metamaterial may in principle support a resonant radiating mode, even if the total size of the radiator is significantly smaller than the wavelength of operation. In those theoretical analyses, MNG metamaterials have been assumed as continuous, isotropic and readily available materials, characterized by a proper dispersion in frequency and by inherent ohmic losses. The fabrication of such compact antennas, however, would require the major effort of designing proper subwavelength inclusions that realize the MNG behavior of the substrate, and consequently a careful design of their geometry, location and orientation. The fabrication of a fully isotropic MNG sample to reside underneath the sub-wavelength patch, moreover, may be challenging with the current technological limitations. In this paper, we first show that the proposed sub-wavelength radiator may operate even when the fabricated MNG sample is not isotropic, due to the specific polarization of the magnetic field in the MNG region. Then, we propose a complete design of the magnetic inclusions, presenting full-wave numerical simulations of the structure, which effectively supports the expected resonant mode, despite the small size of the antenna. The comparisons among analytical results of the patch loaded by: (a) the ideal MNG sample applying a simple cavity model; (b) full-wave numerical simulations of the same antenna considering the presence of the feed; and (c) full-wave numerical simulations of the antenna loaded by the proposed magnetic inclusions, show how our design effectively simulate the presence of an MNG sample, allowing the realistic design of a sub-wavelength metamaterial patch antenna with satisfactory matching and radiating features. This may open up new venues in the realization of efficient metamaterial radiating components for practical purposes.

235 citations

Journal ArticleDOI
TL;DR: In this article, an improved model for analyzing electrically small NRI-TL antennas is proposed, that highlights the methods that enable these antennas to offer a good impedance match and a high radiation efficiency compared to previously reported designs.
Abstract: An improved model for analyzing electrically small NRI-TL antennas is proposed, that highlights the methods that enable these antennas to offer a good impedance match and a high radiation efficiency compared to previously reported designs. An even-odd mode analysis reveals that the antenna supports a predominately even-mode current on the vertical vias, allowing the antenna to be modeled using a multiple folded monopole topology, which provides a substantial increase in the radiation resistance of the antenna. This, together with the top-loading effect of the microstrip line on the vias, enables the antenna to be matched to 50 Omega without the use of an external matching network, while maintaining a high radiation efficiency. The validity of the proposed model is confirmed with a fabricated prototype, that consists of four microstrip zero-degree NRI-TL unit cells with dimensions of lambda0/10 times lambda0/10 times lambda/20 over a 0.45lambda0 times 0.45lambda0 ground plane. The antenna's performance is verified by full-wave simulations and experimental data obtained at 3.1 GHz, which yield a vertical linear electric field polarization, a measured -10dB return-loss bandwidth of 53 MHz and a measured efficiency of 70%.

147 citations