Beam-switching antennas for millimeter-wave communications
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Journal Title
Journal ISSN
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School of Electrical Engineering |
Doctoral thesis (article-based)
| Defence date: 2021-10-22
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Author
Date
2021
Major/Subject
Mcode
Degree programme
Language
en
Pages
86 + app. 80
Series
Aalto University publication series DOCTORAL DISSERTATIONS, 137/2021
Abstract
Millimeter-wave frequencies, i.e. 30-300 GHz, are being widely adopted in commercial applications such as communication systems, radar, and imaging. At millimeter-wave frequencies, the antennas need to be directive to mitigate the higher free-space loss and atmospheric attenuation. In addition, the beam steering capability helps to extend the coverage to a wide angular range. The objective of the thesis is to develop high-gain and wide beam-steering antennas based on the beam-switching topology. The thesis contributes to the improvement of the integrated lens antenna (ILA) and the feed beam-switching network (BSN) performance. The ILAs are evaluated in terms of form-factor and scan-loss reduction and efficiency improvement. The study of BSN is aimed towards insertion loss reduction and enabling beam reconfigurability. An elliptical ILA with a focal length to diameter ratio, f/d, of 1.1 and a diameter of 160 mm is designed to meet the gain and beam-steering regulations for the point-to-point link antennas operating at 71-76 GHz. The f/d of an elliptical ILA is reduced to 0.88 by using the high permittivity material. An integrated metal-plate lens (IMLA), a combination of the dielectric and metal-plate lens, is proposed to reduce the focal length. The IMLA with 0.69 f/d is designed to achieve a total efficiency of 64% in comparison to 45% of the traditional ILA. The radiation pattern tilting of the offset feeds along the focal plane improved the scan loss of the IMLA by 3.5 dB compared to a traditional ILA. Furthermore, the reduction of scan loss and the extension of the beam steering range of the hemispherical ILA is achieved by positioning the feeds along the spherical surface. The second part of the thesis focuses on the BSN. The numerical study demonstrates that the ILA radiation properties are mostly affected by the radiation pattern distortion of the beam-switching feed array rather than the coupling between the feed ports. The BSN of the Rotman lens fed array is implemented with the 4-channel vector modulator (VM) instead of the RF-switch to minimize the insertion loss. The Rotman lens-based array uses the 1×4 SIW-fed microstrip patch antenna arrays as the radiating elements and a novel easy-to-implement admittance control mechanism is demonstrated for the SIW-fed series arrays. The beam-configurability of the Rotman lens-based array is attained by simultaneous excitation of the beam ports with the VM, which varies the half power beamwidth from 18° to 75°.Description
Supervising professor
Viikari, Ville, Assoc. Prof., Aalto University, Department of Electronics and Nanoengineering, FinlandThesis advisor
Ala-Laurinaho, Juha, Dr., Aalto University, FinlandKeywords
beam reconfigurable, beam-switching, integrated lens antenna, low-profile, millimeter-wave antennas, Rotman lens, scan loss
Other note
Parts
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[Publication 1]: S. K. Karki, J. Ala-Laurinaho, V. Viikari, and R. Valkonen, “Lens Antenna Design for E-band Point-to-point Radio Links,” in Proceedings of the 38th Progress In Electromagnetics Research Symposium - Spring (PIERS), St. Petersburg, Russia, 22-25 May 2017, pp. 1625-1631.
DOI: 10.1109/PIERS.2017.8262010 View at publisher
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[Publication 2]: S. K. Karki, J. Ala-Laurinaho, A. Karttunen, and V. Viikari, “Integrated Lens Antennas for E-band,” in Proceedings of the 48th European Microwave Conference (EuMC), Madrid, Spain, 23-27 Sept. 2018, pp. 1151-1154.
Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201901301406DOI: 10.23919/EuMC.2018.8541385 View at publisher
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[Publication 3]: A. E. I. Lamminen, S. K. Karki, A. Karttunen, M. Kaunisto, J. Säily, M. Lahdes, J. Ala-Laurinaho, and V. Viikari, “Beam-Switching Dual-Spherical Lens Antenna with Low Scan Loss at 71–76 GHz,” IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 10, pp. 1871-1875, October 2018.
DOI: 10.1109/LAWP.2018.2868543 View at publisher
- [Publication 4]: S. K. Karki, J. Ala-Laurinaho, and V. Viikari, “Integrated Metal-lens Antennas with Reduced Height at 71–76 GHz,” in Proceedings of the 13th European Conference on Antennas and Propagation (EuCAP), Krakow, Poland, 31 Mar.-5 Apr. 2019, pp. 1-5
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[Publication 5]: S. K. Karki, J. Ala-Laurinaho, and V. Viikari, “Low-profile Scanloss- Reduced Integrated Metal-Lens Antenna,” IEEE Transactions on Antennas and Propagation, 2021, 12 pages.
DOI: 10.1109/TAP.2021.3111192 View at publisher
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[Publication 6]: S. K. Karki, J. Ala-Laurinaho, V. Viikari, and R. Valkonen, “Effect of Mutual Coupling Between Feed Elements on Integrated Lens Antenna Performance,” IET Microwaves, Antennas & Propagation, vol. 12, no. 10, pp. 1649-1655, August 2018.
DOI: 10.1049/iet-map.2017.1082 View at publisher
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[Publication 7]: S. K. Karki, M. Varonen, M. Kaunisto, A. Rantala, M. Lahti, A. Lamminen, J. Holmberg, M. Kantanen, J. Ala-Laurinaho, and V. Viikari, “Beam- Reconfigurable Antenna Based on Vector Modulator and Rotman Lens on LTCC,” IEEE Access, vol. 9, pp. 52872-52882, March 2021.
DOI: 10.1109/ACCESS.2021.3070037 View at publisher
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[Publication 8]: S. K. Karki, J. Ala-Laurinaho, J. Zheng, M. Lahti, and V. Viikari, “Millimeter Wave Stepped Series Array with LTCC,” in Proceedings of the 49th European Microwave Conference (EuMC), Paris, France, 1-3 Oct. 2019, pp. 956-959.
DOI: 10.23919/EuMC.2019.8910765 View at publisher
