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High Frequency Microwave and Antenna Devices based on Transformation Optics and Glide-Symmetric Metasurfaces
KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.ORCID iD: 0000-0002-8608-0640
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The new generation of wireless communication networks intends to support data rate of Gbit/s. One solution to make it possible is to move upwards in frequency range to employ the unused spectrum in mm-wave frequencies. This brings new challenges in the design of hardware for the communication networks, namely high free space path loss and expensive manufacturing. In this thesis, transformation optics and glide symmetry are employed to address these new challenges for the design of high frequency microwave components and lens antennas.

Transformation optics provides a systematic tool to manipulate electromagnetic waves in a desired way. In this thesis, this tool has been used to improve the radiation properties of conventional homogeneous three-dimensional lenses and compress the size of two-dimensional graded-index lenses.

Glide symmetry is a subset of higher-order symmetries and is described by a translation followed by a reflection with respect to a defined plane. Periodic structures possessing glide symmetry exhibit interesting properties. In this thesis, four of these properties are explored and possible applications are discussed.

First, it is demonstrated that the first mode in a glide-symmetric periodic structures is significantly less dispersive than the corresponding conventional non-glide structure. This property was employed to design fully metallic wideband metasurface-based antennas. The losses in this type of antennas are only ohmic which make them suitable for high frequency applications. Second, it is shown that anisotropic glide-symmetric periodic structures can provide higher levels of anisotropy compared to their conventional periodic counterparts. This property is employed to design compressed two-dimensional lenses. Third, it is demonstrated that glide symmetry can be used to match the impedance of two vastly different dielectric media in a parallel plate waveguide configuration by enhancing the magnetic properties. This property was used to match the profile of two-dimensional homogeneous lenses. Fourth it is shown that glide-symmetric holey metallic structures achieve a significantly wider stop-band compared to conventional non-glide periodic structures. This property is exploited to design cost-effective waveguiding structures and microwave components at mm-wave frequencies. Furthermore, using this property, a flange design that provides contact-less measurement at mm-wave frequencies is presented.

Abstract [sv]

Den nya generationen trådlösa kommunikationsnätverk avser stödja datahastigheter upp till Gbit per sekund. En lösning för att göra det möjligt är att kommunicera på högre frekvenser där det oanvända spektrumet för mm-vågor kan nyttjas. Kommunikation på höga frekvenser medför nya utmaningar i utformningen av hårdvara för kommunikationsnäten, nämligen hög förlust i frirymds-vågutbredningen och höga tillverkningskostnader. I denna avhandling används transformationsoptik och glidsymmetri för att möta dessa nya utmaningar i designen av högfrekventa mikrovågskomponenter och linsantenner.

Transformationsoptik tillhandahåller ett systematiskt verktyg för att manipulera elektromagnetiska vågor på önskat sätt. I denna avhandling har detta verktyg använts för att förbättra strålningsegenskaperna för konventionella homogena 3-dimensionella linser och komprimera storleken av 2-dimensionella inhomogena linser.

Glidsymmetri är en typ av högre symmetri och den beskrivs av en förskjutning följt av en reflektion med avseende på ett definierat plan. Periodiska strukturer med glidsymmetri uppvisar attraktiva egenskaper. I denna avhandling undersöks fyra av dessa egenskaper och möjliga tillämpningar diskuteras.

Först demonstreras att den första moden i en glidsymmetrisk periodisk struktur har betydligt lägre frekvensberoende än i motsvarande konventionellt periodiska struktur. Den här egenskapen har använts föratt designa helt metalliska bredbandiga metayt-baserade linsantenner. I denna antenntyp uppkommer enbart ohmiska förluster i metallen vilket gör den lämplig för högfrekvensapplikationer. För det andra visas det att anisotropa glidsymmetriska periodiska strukturer kan uppnå högre nivåer av anisotropi jämfört med deras konventionella periodiska motsvarighet. Den här egenskapen används för att designa komprimerade tvådimensionella linser. För det tredje demonstreras att glidsymmetri kan användas för att matcha impedansen för två olika dielektriska medier i parallellplåt-vågledarkonfiguration genom att utöka de magnetiska egenskaperna. I denna avhandling har detta använts för att impedansanpassa tvådimensionella homogena linser. För det fjärde visas att en glidsymmetrisk gropig metallisk struktur uppnår betydligt bredare stoppband jämfört med den gropiga periodiska strukturen utan glidsymmetri. Den här egenskapen har utnyttjats för att utforma kostnadseffektiva vågledare och mikrovågskomponenter för mm-vågfrekvenser. Slutligen används denna egenskap för att designa en fläns som som möjliggör kontaktlösa mätningar vid mm-vågfrekvenser.

Place, publisher, year, edition, pages
Stockholm, Sweden: KTH Royal Institute of Technology, 2019. , p. 78
Series
TRITA-EECS-AVL ; 2019:84
Keywords [en]
Glide Symmetry, Transformation Optics, Lens Antennas, High Frequency, Microwave Devices
National Category
Communication Systems
Research subject
Electrical Engineering
Identifiers
URN: urn:nbn:se:kth:diva-263889ISBN: 978-91-7873-376-7 (print)OAI: oai:DiVA.org:kth-263889DiVA, id: diva2:1370996
Public defence
2019-12-11, Kollegiesalen, Brinellvägen 8, Stockholm, 13:30 (English)
Opponent
Supervisors
Note

QC20191119

Available from: 2019-11-19 Created: 2019-11-18 Last updated: 2019-11-19Bibliographically approved
List of papers
1. Bespoke Lenses Based on Quasi-Conformal Transformation Optics Technique
Open this publication in new window or tab >>Bespoke Lenses Based on Quasi-Conformal Transformation Optics Technique
2017 (English)In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 65, no 5, p. 2256-2264Article in journal (Refereed) Published
Abstract [en]

In this paper, a systematic method to design a quasioptimum lens profile based on quasi-conformal transformation optics technique for a given excitation is presented. This method is applied to a number of conventional antennas, such as an aperture and a log-spiral slot. In all these configurations, an increase of the directivity is observed. Furthermore, using this method, a quasi-optimum graded index lens for a broadband enhanced leaky slot excitation is designed and the results are compared with a hyperhemispherical lens with and without matching layers. Our proposed methodology demonstrates to be able to increase the directivity, to reduce the sidelobes and the cross polarization in a broad bandwidth from 20 to 70 GHz. Due to the continuously changed dielectric constant of the lens profile, reflections are also reduced considerably inside the lens.

Place, publisher, year, edition, pages
IEEE, 2017
Keywords
Graded index (GRIN) lenses, lens antennas, quasi-conformal transformation optics (QCTO)
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-207892 (URN)10.1109/TAP.2017.2679494 (DOI)000400922600014 ()2-s2.0-85018860865 (Scopus ID)
Note

QC 20170530

Available from: 2017-05-30 Created: 2017-05-30 Last updated: 2019-11-18Bibliographically approved
2. Experimental Validation of a Bespoke Lens for a Slot log-spiral Feed
Open this publication in new window or tab >>Experimental Validation of a Bespoke Lens for a Slot log-spiral Feed
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-263885 (URN)
Note

QCR 20191126

Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2019-11-26Bibliographically approved
3. Ultrawideband Metasurface Lenses Based on Off-Shifted Opposite Layers
Open this publication in new window or tab >>Ultrawideband Metasurface Lenses Based on Off-Shifted Opposite Layers
2016 (English)In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 15, p. 484-487Article in journal (Refereed) Published
Abstract [en]

Metasurfaces have demonstrated to be a low-cost solution for the development of directive antennas at high frequency. One of the opportunities of metasurfaces is the possibility to produce planar lenses. However, these lenses usually present a narrow band of operation. This limitation on bandwidth is more restrictive when the required range of refractive index is high. Here, we present a novel implementation of metasurfaces with low dispersion that can be employed for the design of ultrawide-band planar lenses. The implementation consists of two mirrored metasurfaces that are displaced exactly a half unit cell. This displacement produces two effects: It increases the equivalent refractive index of the fundamental mode and flattens its frequency dependence.

Keywords
Luneburg lens, metasurfaces, parallel-plate waveguide, ultrawideband lens
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Telecommunications
Identifiers
urn:nbn:se:kth:diva-185389 (URN)10.1109/LAWP.2015.2492678 (DOI)000372419900010 ()2-s2.0-84964325564 (Scopus ID)
Note

QC 20160418

Available from: 2016-04-18 Created: 2016-04-18 Last updated: 2019-11-18Bibliographically approved
4. Broadband Planar Leaky Wave Antenna Using Glide-symmetric Meandered Transmission Line
Open this publication in new window or tab >>Broadband Planar Leaky Wave Antenna Using Glide-symmetric Meandered Transmission Line
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-263887 (URN)
Note

QC 20191126

Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2019-11-26Bibliographically approved
5. Ultrawideband Anisotropic Glide-Symmetric Metasurfaces
Open this publication in new window or tab >>Ultrawideband Anisotropic Glide-Symmetric Metasurfaces
2019 (English)In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 18, no 8, p. 1547-1551Article in journal (Refereed) Published
Abstract [en]

This letter presents a method to realize anisotropic two-dimensional designs with wideband operation. Glide symmetry has been proven to increase the bandwidth and equivalent refractive index of periodic structures. Here, two anisotropic glide-symmetric unit cells are proposed and characterized. Our simulated results prove that these unit cells follow the general behavior of periodic structures possessing glide symmetry. Moreover, we demonstrate that higher level of anisotropy can also be achieved by glide symmetry. Combining our proposed anisotropic glide-symmetric unit cell and transformation optics, a 30% compressed Luneburg lens is designed. The lens operates from 1 to 13 GHz.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Anisotropy, glide symmetry, Luneburg lens, metasurfaces, transformation optics
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-257559 (URN)10.1109/LAWP.2019.2922238 (DOI)000480310900003 ()2-s2.0-85070460292 (Scopus ID)
Note

QC 20190924

Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-11-18Bibliographically approved
6. Wide Angle Impedance Matching Using Glide-symmetric Metasurfaces
Open this publication in new window or tab >>Wide Angle Impedance Matching Using Glide-symmetric Metasurfaces
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
Abstract [en]

This letter demonstrates that glide symmetry can be used to match the impedance of highly dense dielectric profiles in wide angle and broad bandwidth. Using glidesymmetric metasurfaces permits tuning the magnetic properties of materials, so high values of permittivity can be matched to free space in wide band. This matching is achieved without disturbing the performance of the device since the refractive index remains fixed. The performance of the proposed matching method is validated through measurements for normal incidence. For oblique incidence, a hyperbolic dielectric lens is matched with glide-symmetric structures in simulations. These simulations demonstrate a smooth transmission of the fields manifesting a well-matched profile of the lens.

National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-263888 (URN)
Note

QC 20191126

Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2019-11-26Bibliographically approved
7. Design Guidelines for Gap Waveguide Technology Based on Glide-Symmetric Holey Structures
Open this publication in new window or tab >>Design Guidelines for Gap Waveguide Technology Based on Glide-Symmetric Holey Structures
2017 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 27, no 6, p. 542-544Article in journal (Refereed) Published
Abstract [en]

The behavior of a glide-symmetric holey periodic structure as electromagnetic bandgap is studied in this letter. A number of numerical simulations have been carried out in order to define the importance of each constituent parameter of the unit cell. Our proposed structure finds potential application in antennas and circuits based on gap waveguide technology for the millimeter band. The experimental verifications confirm the effects previously analyzed with the numerical studies.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
Gap waveguide, glide symmetry, holey electromagnetic bandgap (EBG), metasurfaces, parallel plate mode
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-210426 (URN)10.1109/LMWC.2017.2701308 (DOI)000403292100004 ()2-s2.0-85019952743 (Scopus ID)
Note

QC 20170703

Available from: 2017-07-03 Created: 2017-07-03 Last updated: 2019-11-18Bibliographically approved
8. Wideband glide-symmetric holey structures for gap-waveguide technology
Open this publication in new window or tab >>Wideband glide-symmetric holey structures for gap-waveguide technology
2017 (English)In: 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1658-1660, article id 7928356Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, the stop-band of two different holey glide-symmetric EBG lattices is studied. The results show that glide-symmetric EBG structures have potential to achieve wide stop-bands by polygonal lattices. Potential application of the proposed EBG structure in gap-waveguide technology is discussed in the second part of the paper.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
gap-waveguide technology, gliide symmetry, holey EBG, integrated waveguide circuits
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-209639 (URN)10.23919/EuCAP.2017.7928356 (DOI)000403827301151 ()2-s2.0-85020204767 (Scopus ID)9788890701870 (ISBN)
Conference
11th European Conference on Antennas and Propagation, EUCAP 2017, Paris, France, 19 March 2017 through 24 March 2017
Note

QC 20170622

Available from: 2017-06-22 Created: 2017-06-22 Last updated: 2019-11-18Bibliographically approved
9. Cost-Effective Gap Waveguide Technology Based on Glide-Symmetric Holey EBG Structures
Open this publication in new window or tab >>Cost-Effective Gap Waveguide Technology Based on Glide-Symmetric Holey EBG Structures
2018 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 66, no 2, p. 927-934Article in journal (Refereed) Published
Abstract [en]

We present a novel electromagnetic bandgap (EBG) structure, which can be used to manufacture low-cost waveguiding structures at high frequencies. The unit cell of the proposed EBG consists of glide-symmetric holes in parallel plate waveguide. Using this unit cell in groove gap waveguide technology has a number of advantages over pin-type EBG at high frequencies, such as acquiring higher accuracy because of larger periodicity as well as an easier and cheaper manufacturing process. The performance of the proposed waveguiding structure is demonstrated using both a straight and a double 90 degrees bent lines through simulation and measurement.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Gap waveguide technology, glide symmetry, higher symmetries
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-223516 (URN)10.1109/TMTT.2017.2764091 (DOI)000424464900032 ()
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), PT2014-5813
Note

QC 20180222

Available from: 2018-02-22 Created: 2018-02-22 Last updated: 2019-11-18Bibliographically approved
10. Wideband Phase Shifter in Groove Gap Waveguide Technology Implemented With Glide-Symmetric Holey EBG
Open this publication in new window or tab >>Wideband Phase Shifter in Groove Gap Waveguide Technology Implemented With Glide-Symmetric Holey EBG
2018 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 6, p. 476-478Article in journal (Refereed) Published
Abstract [en]

A wideband phase shifter in U-band realized in groove gap waveguide (GGWG) technology is presented as a good solution to be integrated in antenna feed structures. The GGWG is implemented by glide-symmetric holes to reduce manufacturing complexity. The design is also proposed to be mechanically variable by changing the height of the dielectric slab used to change the phase. Experimental results evidence the potential of this solution.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Glide symmetry, groove gap waveguide (GGWG), phase shifter
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-231203 (URN)10.1109/LMWC.2018.2832013 (DOI)000434448900008 ()2-s2.0-85047021548 (Scopus ID)
Note

QC 20180629

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2019-11-18Bibliographically approved
11. Design of microwave components in groove gap waveguide technology implemented by holey EBG
Open this publication in new window or tab >>Design of microwave components in groove gap waveguide technology implemented by holey EBG
2017 (English)In: 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 746-748, article id 7928587Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, the feasibility of the implementation of microwave components in groove gap waveguide technology by glide-symmetry holey EBG is discussed. Using this technology, microwave components and antennas which were previously designed for hollow metallic waveguides can be manufactured in a cost-effective way at high frequencies. To show the viability of the proposed solution a phase shifter and a mode converter are designed as examples of typical components for antenna systems.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
Gap-waveguide technology, Glide symmetry, holey EBG, Integrated waveguide circuits, microwave components
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-209641 (URN)10.23919/EuCAP.2017.7928587 (DOI)000403827300156 ()2-s2.0-85020218510 (Scopus ID)9788890701870 (ISBN)
Conference
11th European Conference on Antennas and Propagation, EUCAP 2017, Paris, France, 19 March 2017 through 24 March 2017
Note

QC 20170622

Available from: 2017-06-22 Created: 2017-06-22 Last updated: 2019-11-18Bibliographically approved
12. Using Glide-Symmetric Holes to Reduce Leakage Between Waveguide Flanges
Open this publication in new window or tab >>Using Glide-Symmetric Holes to Reduce Leakage Between Waveguide Flanges
2018 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 6, p. 473-475Article in journal (Refereed) Published
Abstract [en]

In this letter, a novel cost-effective flange is proposed to prevent the leakage created by undesired air gaps between flanges of two mating waveguides. The cause of an undesired gap can be surface curvature, dirt, human mistakes, or misalignment. Our proposal consists of machining glide-symmetric holes around the waveguide aperture on the flanges. Due to the glide symmetry properties, an identical pattern of the holes is possible at both sides, thus becoming glide-symmetric when they are mated together.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Contact-less measurement, electromagnetic bandgap (EBG), glide symmetry, waveguide flange
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-231202 (URN)10.1109/LMWC.2018.2824563 (DOI)000434448900007 ()2-s2.0-85045974264 (Scopus ID)
Note

QC 20180629

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2019-11-18Bibliographically approved

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