mtm resonant antennas

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR) Special Edition on Adv anced Tec hnique of Estimation Applic ations in Electr ical Engine ering, June 2013 e-ISSN: 2321-1814 ISBN (Print): 978-1-62776-478 -0 MTM Resonant Antennas Mohammad Alibakhshi Kenari [email protected] Abstract I n this paper, two novel ultra wideband (UWB) minimized anten- nas based on the composite right/left-handed transmission line (CRLH-TL) structures are designed. Keywords Ultra wide band (UWB) antennas , Minimized ant ennas, Metamater ial (MTM) . Introduction Transmission lines (TLs) are fundamental ingredients in modern communication syste ms, b eing applied to connec t antennas to trans ceivers. When the electrica l wavelengths are shorter than or comparable to the physical dimensions of a network, the length becomes important and transmission line theory should be applied instead of standard circuit analysis. Therefore high frequency TLs can be specied as TLs which are modelled for transport electromagnetic waves whose wavelengths are shorter than or comparable to the length of the line. The general TL approach furnishes insight into the physical phenomena of LH mater ials and provides an ecie nt design tool for LH applications. The LH/TL structures with lower loss and broader bandwidth have led to the development of recent microwave devices. Electrical Engineering Department of Shahid Bahonar University of Kerman, Iran Mohammad Alibakhshi Kenari MTM Resonant Antennas. Page 1 of  9

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Page 1: MTM Resonant Antennas

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

MTM Resonant AntennasMohammad Alibakhshi Kenari ∗

[email protected]

Abstract

In this paper, two novel ultra wideband (UWB) minimized anten-nas based on the composite right/left-handed transmission line(CRLH-TL) structures are designed.

Keywords

Ultra wide band (UWB) antennas, Minimized antennas, Metamaterial (MTM).

Introduction

Transmission lines (TLs) are fundamental ingredients in modern communicationsystems, being applied to connect antennas to transceivers. When the electricalwavelengths are shorter than or comparable to the physical dimensions of anetwork, the length becomes important and transmission line theory should beapplied instead of standard circuit analysis. Therefore high frequency TLs canbe specified as TLs which are modelled for transport electromagnetic waveswhose wavelengths are shorter than or comparable to the length of the line.

The general TL approach furnishes insight into the physical phenomena of LH

materials and provides an efficient design tool for LH applications. The LH/TLstructures with lower loss and broader bandwidth have led to the developmentof recent microwave devices.

∗Electrical Engineering Department of Shahid Bahonar University of Kerman, Iran

Mohammad Alibakhshi KenariMTM Resonant Antennas.

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

Metamaterials are artificially made materials which have electromagnetic specifi-cations not found in nature. The concept of MTMs with simultaneously negativepermittivity and permeability, more commonly referred to as left/handed ma-terials. In fact, a purely left/handed TL is not physical and can never berealized because of the parasitic effects. MTMs with left/handed propertieshave inevasible right/handed properties, known as composite right/left handMTMs. During the past years, composite right/left/handed materials madeby inserting periodic inclusions [1] with dimensions smaller than the guidedwavelength, p << λg, have attracted considerable attention in view of min-

imizing antenna size [2], which may lead to the development of new applications.

In this paper, we proposed UWB minimized antennas based on CRLH MTM/TLsfor communication units, radars and location tracing. In design proposed an-tennas structures recommending and utilizing of the novel methodologies forantennas size reduction based on MTMTLs and printed planar and for antennasbandwidth and radiation properties enhancement based on select and optimizeof the inductive and capacitive elements, as presented approaches detailed atnext section.

The paper is categorized as follows. We will propose and designing two MTM

antennas which have smaller size, broader bandwidth and superior radiationproperties in comparison to conventional and UWB antennas, in Section II, andfinally discussion and conclusion are raised.

Design Procedures of Recommended Antenna

Prototype

The proposed antennas are based on the CRLH MTM/TL unit cells. Theseplanar antennas are designed on a Rogers RT Duroid5880 substrate with di-electric constant of 2.2 and 1.6 mm thickness. These antennas are based on

simplified planar mushroom structure unit cells. The unit cells are consists of host TLs with ψ/shaped gaps printed into radiation patches and rectangularand spiral inductors connected to ground plane through metallic via holes asset ups series capacitances C L and shunt inductances LL. Even if we provideonly C L and LL, parasitic series inductance LR and shunt capacitance C Reffects will unavoidably befall owing to currents flowing in the metallization andvoltage gradients expanding between the metal patterns of the trace and theground, that infers that the LR and C R cannot be relinquished, hence a purely

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

left/handed transmission line cannot be physically. Thus, the CRLH modelrepresents the most general MTM structure possible. Antenna structures areexcited by external port (i.e.; port 1) and their port 2 are matched to 50Ω loadimpedance. CRLH propagation along a given direction can be modelled by the8-parameter unit cell lumped element circuit shown in figures [?] and [?]. Thesemodels essentially exhibits a series capacitance C L and a shunt inductanceLL [left/handed (LH)], corresponding to negative permeability and negativepermittivity, respectively, but also includes a series inductance LR and a shuntcapacitance C R [right/handed (RH)] associated with the magnetic and electricfluxes, respectively, intrinsic to any TL structures, and corresponding to positive

permeability and permittivity, respectively. In addition to these four reactiveparameters, one has the conventional lossy parameters RR and GR (RH), andthe lossy parameters GL and RL (LH), which account for the dielectric lossassociated with C L and the ohmic loss associated with LL, respectively, andwhich mostly represent radiation in antenna applications.

In these designs, we presented a new theory based on employing printed planermethodology and CRLH MTM/TL for downsizing of proposed antennas andalso we utilizing approaches based on designing useful capacitive and inductiveelements for antenna bandwidth enhancement and maximizing of the radiationproperties of the proposed antennas.

Design Procedure of the UWB Minimized MTM Antenna Based onFour ψ-Shaped Unit Cells

Presented antenna is formed of the four simplified planar mushroom structure psi/shaped unit cells, each of which occupies only 6.2 mm x 9.5 mm or 0.1λ0

x 0.158λ0 in terms of the free space wavelength at the operation frequency f = 5 GHz. The physical length, width and height of the antenna are 24.8 mm,9.5 mm, 1.6 mm, respectively, or, 0.41λ0 x 0.158λ0 x 0.02λ0. The equivalentcircuit model of the antenna for one unit cell and whole layout structure basedon the CRLH/TL are shown in figure 1 and 2, respectively.

Beside the small size, we utilizing approaches based on designing usefulcapacitive and inductive elements for antenna bandwidth enhancement andmaximizing of the radiation properties of the antennas to good satisfy the severeneeds of modern commercial applications. These approaches as following; asmaller value of the loaded series capacitance may be increase bandwidth and

this smaller value will be realized by implementation of the ψ/shaped gaps withclosely space edges printed into radiation patches. This way result to increase

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

Figure 1: Circuit model for one unit cell of a CRLH TL metamaterial structure with RH parameters ( LR; RR; C R; GR) and LH parameters ( C L; GL; LL; RL).

the bandwidth of the antenna as providing a ultra wideband (UWB) antennawith 9 GHz bandwidth, from 2.8/11.8 GHz, for V S W R < 2, which correspond-ing to 123.28% bandwidth and also with employing rectangular inductor with

one turn that through a via hole with suitable dimension connected to groundplane, the aperture efficiency of the antenna can extend, thus, the antennagain and radiation efficiency are increased. The antenna gain and radiationefficiency at resonance frequency 8 GHz are 5.29 dBi and 30.83%, respectively.

The simulated reflection coefficient (S 11 < /10dB) and radiation gain patternat 8 GHz are plotted in figure 3 and 4, respectively.

Figure 2: Geometry of the antenna structure composed of four unit cells.

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

Figure 3: Simulated reflection coefficient (S11 parameter).

Figure 4: Simulated gain pattern in elevation plane ( φ = 0o) at f r = 8 GHz.

Extended Bandwidth Design for CRLH-TL Based Small Antenna

In this section, we present the printed ψ/shaped antenna structure that con-structed of three unit cells with extended bandwidth in comparison to proposedantenna in previous section. The design procedures of both proposed antennasare completely similar together, but number of unit cells contribution in anten-nas structures, circuit models and layout structures of two antennas are differentwith together. These proposed difference caused which later proposed antennaproviding enhancement bandwidth than designed first antenna. Equivalentcircuit model for the unit cell and entire structure of this antenna are shown in

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

figure 5 and 6, respectively.

As obviously in design of later antenna for extend the bandwidth, arrangement

Figure 5: Circuit model for one unit cell of a CRLH TL metamaterial structure.

Figure 6: Configuration of the antenna structure composed of three unit cells.

and number unit cells accompanying inductive elements are changed than firstantenna, which result to increasing overall size of this antenna than first antenna.This antenna covers frequency bandwidth from 2.1/ 11.7 GHz and consist of 9.6 GHz bandwidth which corresponding to 139.13% operational bandwidth.

Overall size of antenna is 37.2 x 9.25 x 1.6 mm3

or, 0.62λ0 x 0.154λ0 x 0.02λ0 interms of the free space wavelength at the operation frequency f = 5 GHz. The

antenna gain and radiation efficiency at f r = 5 GHz are 5.55 dBi and 35.22%,respectively. The simulated reflection coefficient (S11 < -10dB) and radiationgain pattern at 5 GHz are plotted in figure 7 and 8, respectively.

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0

Figure 7: Simulated S11 parameter.

Figure 8: Simulated radiation gain pattern in ( φ = 0o) and at f r = 5 GHz.

Conclusion

In this paper, we have introduced a new concept of antenna size reductionbased on MTM design technology and printed planar methodology and also anovel idea of antenna bandwidth enhancement accompanying superior radiationproperties based on employing appropriate capacitive and inductive elementsattending their optimize values. All results demonstrated that the proposedCRLH/based antennas have wider bandwidth, smaller size and superior radiationproperties in comparison to other conventional and UWB antennas. Theseantennas have the advantages of small size, UWB, lightweight, high gain andefficiency, unidirectional radiation patterns, simple implementation and low cost.The simulated results exhibit that the proposed antennas should be potentialcandidates to use in the modern wireless communication systems, radars andlocation tracing.

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0 References

Acknowledgement

The author would like to express his sincere thanks to Research Institute forICT of Iran (Contract number 6987/500/T).

References

[1] A. Lai, C. Caloz, and T. Itoh, Composite Right/Left/Handed

Transmission Line Metamaterials, IEEE Microwave Magazine, Sep.2004.

[2] Jofre, L., Cetiner, B.A., and F. De Flaviis, Miniature Multi/Element

Antenna for Wireless Communications, IEEE Trans. AntennasPropag., vol. 50, pp. 658/669, May, 2002.

[3] Mohammad Alibakhshi Kenari, A New UWB Small Dimension MTM

Antennas Based on CRLH Transmission Lines for Modern Wireless

Communication Systems and Portable Devices, HCTL Open Interna-tional Journal of Technology Innovations and Research, Volume 2, March2013, Pages 25-55, ISSN: 2321-1814, ISBN: 978-1-62776-111-6.

[4] Mohammad Alibakhshi Kenari, Squeeze Broad-Band Patch

Antenna Based on Metamaterial Transmission Line for PortableApparatus, HCTL Open International Journal of Technology Innovationsand Research, Volume 2, March 2013, Pages 56-66, ISSN: 2321-1814, ISBN:978-1-62776-111-6.

[5] Mohammad Alibakhshi Kenari, A Novel Compact Ultra Wide Band

Planar Antenna Based on the Composite Right/Left-Handed

Transmission Line Accompanying Improvement Gain, HCTL Open

International Journal of Technology Innovations and Research, Volume 2,March 2013, Pages 67-77, ISSN: 2321-1814, ISBN: 978-1-62776-111-6.

[6] Ali. Rostami, Seyed Yousef. Shafiei, Farid. Alidoust Aghdam,

Optimization of Microstrip Antenna Characteristics Using

Photonic Band Gap Structure, HCTL Open International Journalof Technology Innovations and Research, Volume 3, May 2013, ISSN:2321-1814, ISBN: 978-1-62776-443-8.

[7] Arpit Nagar, Aditya Singh Mandloi and Vishnu Narayan Saxena,Electro-magnetic Bandgap of Microstrip Antennas, HCTL Open In-

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HCTL Open Int. J. of Technology Innovations and Research (IJTIR)Special Edition on Advanced Technique of Estimation Applications inElectrical Engineering, June 2013e-ISSN: 2321-1814ISBN (Print): 978-1-62776-478-0 References

ternational Journal of Technology Innovations and Research, Volume 3,May 2013, ISSN: 2321-1814, ISBN: 978-1-62776-443-8.

This article is an open access article distributed under the terms and con-ditions of the Creative Commons Attribution 3.0 Unported License (http:

//creativecommons.org/licenses/by/3.0/ ).

c2013 by the Authors. Licensed and Sponsored by HCTL Open, India.

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