umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Topology Optimization of Antennas and Waveguide Transitions
Umeå University, Faculty of Science and Technology, Department of Computing Science. (Computational design optimization)
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis introduces a topology optimization approach to design, from scratch, efficient microwave devices, such as antennas and waveguide transitions. The design of these devices is formulated as a general optimization problem that aims to build the whole layout of the device in order to extremize a chosen objective function. The objective function quantifies some required performance and is evaluated using numerical solutions to the 3D~Maxwell's equations by the finite-difference time-domain (FDTD) method. The design variables are the local conductivity at each Yee~edge in a given design domain, and a gradient-based optimization method is used to solve the optimization problem. In all design problems, objective function gradients are computed based on solutions to adjoint-field problems, which are also FDTD discretization of Maxwell's equations but solved with different source excitations. For any number of design variables, the computation of the objective function gradient requires one solution to the original field problem and one solution to the associated adjoint-field problem. The optimization problem is solved iteratively using the globally convergent Method of Moving Asymptotes (GCMMA).

By the proposed approach, various design problems, including tens of thousands of design variables, are formulated and solved in a few hundred iterations. Examples of solved design problems are the design of wideband antennas, dual-band microstrip antennas, wideband directive antennas, and wideband coaxial-to-waveguide transitions. The fact that the proposed approach allows a fine-grained control over the whole layout of such devices results in novel devices with favourable performance. The optimization results are successfully verified with a commercial software package. Moreover, some devices are fabricated and their performance is successfully validated by experiments.

Place, publisher, year, edition, pages
Umeå University: Umeå University , 2015. , 29 p.
Keyword [en]
Maxwell's equations, topology optimization, antennas, waveguide transition, finite-difference time-domain, gradient-based optimization, adjoint-field problem, microwave devices.
National Category
Computer Science
Research subject
Computing Science
Identifiers
URN: urn:nbn:se:umu:diva-102505ISBN: 978-91-7601-255-0 (print)OAI: oai:DiVA.org:umu-102505DiVA: diva2:808378
Public defence
2015-05-26, Naturvetarhuset, N450, Umeå universitet, Umeå, 10:15 (English)
Opponent
Supervisors
Available from: 2015-05-05 Created: 2015-04-27 Last updated: 2017-04-11Bibliographically approved
List of papers
1. Topology optimization of UWB monopole antennas
Open this publication in new window or tab >>Topology optimization of UWB monopole antennas
2013 (English)In: 7th European Conference on Antennas and Propagation (EuCAP2013), New York: IEEE conference proceedings, 2013, 1488-1492 p.Conference paper, Published paper (Refereed)
Abstract [en]

A Topology optimization technique is used for complete layout optimization of the radiating element of a planar monopole antenna. The design objective is to find a conductivity distribution that maximizes the energy received by the planar monopole over the frequency band 1-10 GHz. The finite difference time domain method (FDTD) is used for the numerical calculations, and an adjoint problem is derived to calculate the corresponding sensitivities. Numerical results show a promising use of topology optimization techniques for the systematic design of ultrawideband monopoles.

Place, publisher, year, edition, pages
New York: IEEE conference proceedings, 2013
Series
Proceedings of the European Conference on Antennas and Propagation, ISSN 2164-3342
Keyword
adjoint equations, FDTD, Maxwell equations, topology optimization, ultrawideband (UWB)
National Category
Computer Science
Identifiers
urn:nbn:se:umu:diva-79479 (URN)000327126001092 ()978-889070183-2 (ISBN)978-1-4673-2187-7 (ISBN)
Conference
7th European Conference on Antennas and Propagation (EuCAP2013), Gothenburg, Sweden, 8-12 April 2013
Available from: 2013-08-20 Created: 2013-08-20 Last updated: 2017-04-11Bibliographically approved
2. Topology optimization of metallic antennas
Open this publication in new window or tab >>Topology optimization of metallic antennas
2014 (English)In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 62, no 5, 2488-2500 p.Article in journal (Refereed) Published
Abstract [en]

We introduce an approach to carry out layout optimization of metallic antenna parts. An optimization technique first developed for the optimization of load-bearing elastic structures is adapted for the purpose of metallic antenna design. The local conductivity values in a given region are used as design variables and are iteratively updated by a gradient-based optimization algorithm. Given a set of time-domain signals from exterior sources, the design objective is here to maximize the energy received by the antenna and transmitted to a coaxial cable. The optimization proceeds through a sequence of coarsely-defined lossy designs with successively increasing details and less losses as the iterations proceed. The objective function gradient is derived based on the FDTD discretization of Maxwell's equations and is expressed in terms of field solutions of the original antenna problem and an adjoint field problem. The same FDTD code, but with different wave sources, is used for both the original antenna problem and the adjoint problem. For any number of design variables, the gradient is evaluated on the basis of only two FDTD simulations, one for the original antenna problem and another for the adjoint field problem. We demonstrate the capability of the method by optimizing the radiating patch of both UWB monopole and microstrip antennas. The UWB monopole is designed to radiate over a wide frequency band 1-10 GHz, while the microstrip patch is designed for single and dual frequency band operation. In these examples, there are more than 20,000 design variables, and the algorithm typically converges in less than 150 iterations. The optimization results show a promising use of the proposed approach as a general method for conceptual design of near-resonance metallic antennas.

Place, publisher, year, edition, pages
IEEE Press, 2014
Keyword
Adjoint field problem, coaxial feed model, finite-difference time-domain (FDTD), microstrip antennas, topology optimization, ultrawideband antennas (UWB)
National Category
Computer Science
Identifiers
urn:nbn:se:umu:diva-79481 (URN)10.1109/TAP.2014.2309112 (DOI)000336667900018 ()
Available from: 2013-08-20 Created: 2013-08-20 Last updated: 2017-12-06Bibliographically approved
3. Patch and ground plane design of microstrip antennas by material distribution topologly optimization
Open this publication in new window or tab >>Patch and ground plane design of microstrip antennas by material distribution topologly optimization
2014 (English)In: Progress in Electromagnetics Research B, ISSN 1937-6472, E-ISSN 1937-6472, Vol. 59, 89-102 p.Article in journal (Refereed) Published
Abstract [en]

We use a gradient-based material distribution approach to design conductive parts of microstrip antennas in an efficient way. The approach is based on solutions of the 3D Maxwell's equation computed by the finite-difference time-domain (FDTD) method. Given a set of incoming waves, our objective is to maximize the received energy by determining the conductivity on each Yee-edge in the design domain. The objective function gradient is computed by the adjoint-field method. A microstrip antenna is designed to operate at 1.5 GHz with 0.3 GHz bandwidth. We present two design cases. In the first case, the radiating patch and the finite ground plane are designed in two separate phases, whereas in the second case, the radiating patch and the ground plane are simultaneously designed. We use more than 58,000 design variables and the algorithm converges in less than 150 iterations. The optimized designs have impedance bandwidths of 13% and 36% for the first and second design case, respectively.

Place, publisher, year, edition, pages
Electromagnetics Academy, 2014
National Category
Computer Science
Identifiers
urn:nbn:se:umu:diva-87769 (URN)10.2528/PIERB14030605 (DOI)
Available from: 2014-04-09 Created: 2014-04-09 Last updated: 2017-12-05Bibliographically approved
4. Topology Optimization of Planar Antennas for Wideband Near-Field Coupling
Open this publication in new window or tab >>Topology Optimization of Planar Antennas for Wideband Near-Field Coupling
Show others...
2015 (English)In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 63, no 9, 4208-4213 p.Article in journal (Refereed) Published
Abstract [en]

We present an approach to design from scratch planar microwave antennas for the purpose of ultra-wideband (UWB) near-field sensing. Up to about 120 000 design variables associated with square grids on planar substrates are subject to design, and a numerical optimization algorithm decides, after around 200 iterations, for each edge in the grid whether it should consist of metal or a dielectric. The antenna layouts produced with this approach show UWB impedance matching properties and near-field coupling coefficients that are flat over a much wider frequency range than a standard UWB antenna. The properties of the optimized antennas are successfully cross-verified with a commercial software and, for one of the designs, also validated experimentally. We demonstrate that an antenna optimized in this way shows a high sensitivity when used for near-field detection of a phantom with dielectric properties representative of muscle tissue.

Keyword
adjoint-field problem, ultra-wideband antennas (UWB), directivity, Vivaldi antenna, microwave sensing.
National Category
Computer Science
Identifiers
urn:nbn:se:umu:diva-102572 (URN)10.1109/TAP.2015.2449894 (DOI)
Note

Originally published in thesis in manuscript form.

Available from: 2015-04-28 Created: 2015-04-28 Last updated: 2017-12-04Bibliographically approved
5. Time-Domain Sensitivity Analysis for Conductivity Distribution in Maxwell's Equations
Open this publication in new window or tab >>Time-Domain Sensitivity Analysis for Conductivity Distribution in Maxwell's Equations
2015 (English)Report (Other academic)
Abstract [en]

We present expressions for the derivatives of the outgoing signal in coaxial cables with respect to the conductivity distribution in a specific domain. The derived expressions can be used with gradient-based optimization methods to design metallic electromagnetic devices, such as antennas and waveguides. We use the adjoint-field method to derive the expressions and the derivation is based on the 3D time-domain Maxwell's equations. We present two derivative expressions; one expression is derived in the continuous case and the second is derived based on the FDTD discretization of Maxwell's equations, including the uniaxial perfectly match layer (UPML) to simulate the radiation boundary condition. The derivatives are validated through a numerical example, where derivatives computed by the adjoint-field method are compared against derivatives computed with finite differences. Up to 7 digits precision matching is obtained.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2015. 20 p.
Series
UMINF 15.06
Keyword
Maxwell's equations, antennas, waveguide, finite-difference time-domain (FDTD), gradient-based optimization, adjoint-field problem, sensitivity analysis.
National Category
Computer Science
Research subject
Computer Science
Identifiers
urn:nbn:se:umu:diva-79483 (URN)
Note

Originally published in licentiate thesis "Metallic Antenna Design Based on Topology Optimization Techniques",  under the title

"Sensitivity Analysis for Conductive Material Distribution Using the Time-Domain Maxwell’s Equations"

Available from: 2013-08-20 Created: 2013-08-20 Last updated: 2017-04-11Bibliographically approved
6. Topology Optimisation of Wideband Coaxial-to-Waveguide Transitions
Open this publication in new window or tab >>Topology Optimisation of Wideband Coaxial-to-Waveguide Transitions
2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, 45110Article in journal (Refereed) Published
Abstract [en]

To maximize the matching between a coaxial cable and rectangular waveguides, we present a computational topology optimisation approach that decides for each point in a given domain whether to hold a good conductor or a good dielectric. The conductivity is determined by a gradient-based optimisation method that relies on finite-difference time-domain solutions to the 3D Maxwell’s equations. Unlike previously reported results in the literature for this kind of problems, our design algorithm can efficiently handle tens of thousands of design variables that can allow novel conceptual waveguide designs. We demonstrate the effectiveness of the approach by presenting optimised transitions with reflection coefficients lower than −15dB over more than a 60% bandwidth, both for right-angle and end-launcher configurations. The performance of the proposed transitions is crossverified with a commercial software, and one design case is validated experimentally.

Keyword
topology optimization, finite-difference time- domain (FDTD), adjoint-field problem, waveguides, coaxial cable, transitions design, end-launcher.
National Category
Computer Science
Identifiers
urn:nbn:se:umu:diva-102577 (URN)10.1038/srep45110 (DOI)000397137700001 ()
Funder
Swedish Research Council, 621-2013-3706
Available from: 2015-04-28 Created: 2015-04-28 Last updated: 2017-05-12Bibliographically approved

Open Access in DiVA

Topology Optimization of Antennas and Waveguide Transitions(3357 kB)823 downloads
File information
File name FULLTEXT01.pdfFile size 3357 kBChecksum SHA-512
1f84336e66c5da548fba26d88e2c936744de3ee4352dd932c84c47b4028f186dfefa78e0eba1c8f586a52c419abf7937c1d8343bd795ae1613b4fecc33f3434f
Type fulltextMimetype application/pdf
Spikblad(91 kB)15 downloads
File information
File name SPIKBLAD01.pdfFile size 91 kBChecksum SHA-512
a49cc5109d6db17d3b3fdc460c09bd628b6b72abc6cda69cc3508d13979eceee39f53d3d9affed961fb7c3164825add5358aea7ed18ef4e9b832a040a4e484a0
Type spikbladMimetype application/pdf

Search in DiVA

By author/editor
Hassan, Emadeldeen
By organisation
Department of Computing Science
Computer Science

Search outside of DiVA

GoogleGoogle Scholar
Total: 823 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 5937 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf