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Millimetre wave lens and transmitarray antennas for scan loss mitigation

Hill, Timothy A. (2020) Millimetre wave lens and transmitarray antennas for scan loss mitigation Doctoral thesis, University of Surrey.

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Text (The final revised thesis)
thesis.pdf - Accepted version Manuscript
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Video (Chapter 3: 8-element uniform phased array, surface current density (absolute value))
8_element_array_28GHz_corporate_feed_with_patches_uniform_surface_current_abs.gif - Supplemental Material
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Video (Chapter 3: K = 0.25 unequal power divider, surface current density (absolute value))
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Video (Chapter 4: Taylor beta=0 PCB with lenses and matching layers, Hx field cross-section)
array_28GHz_lens7_PCB_boresight_new_mesh_Hx_field_cross_section_0.4_A_m.gif - Supplemental Material
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Video (Chapter 4: Special beta=72 PCB with lenses and matching layers, Hx field cross-section, showing beam steering between lenses)
array_28GHz_lens7_PCB_beta=72_special_new_mesh_v2_Hx_field_cross_section_0.4_A_m.gif - Supplemental Material
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Video (Chapter 4: Taylor beta=144 PCB with lenses and matching layers, Hx field cross-section)
array_28GHz_lens7_PCB_beta=144_new_mesh_correct_PCB_tand=0.04_Hx_cross_section_2.gif
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Video (Chapter 4: Repositioned cascaded Fresnel lenses, H field (absolute value), showing focusing effect)
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Video (Chapter 6: Crossed slot unit cell Ey field and cross-section)
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Video (Chapter 6: Jerusalem cross slot unit cell Ey field and cross-section)
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Video (Chapter 6: Transmitarray beta=0 Ey cross-section)
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Video (Chapter 6: Transmitarray beta=144 Ey cross-section)
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Video (Chapter 6: Transmitarray beta=144 Ey cross-section and whole structure)
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Video (Chapter 4: Taylor beta=144 PCB with lenses and matching layers, Hx field cross-section)
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Abstract

Beam steering impairments adversely affect antenna performance at wider steering angles. Scan loss degrades the antenna gain, and hence the link budget. To address this problem, antennas designs based on phased arrays, lenses, and transmitarrays are proposed. Millimetre wave beamforming within 5G cell sectors is considered as an application scenario. Feed networks for an 8-element phased array, operating at 28 GHz, were designed using unequal power dividers. A Taylor amplitude distribution was applied to reduce the sidelobe level to -15.2 dB at boresight. Prototypes were fabricated in microstrip, using meanders to steer the beam. Cascaded Fresnel lenses were placed around the array, to enhance the gain. By tilting the lenses to align with the steered beam, the lenses increased the gain by 3.19 dB at ±52°, and by a further 1.5 dB when repositioned in simulation. Asymmetric amplitude distributions were applied to the array to prevent the main lobe from splitting. Diffraction theory was used to analyse the focusing properties of the lens arrangement. The fabricated prototype exhibited a bandwidth of 1.75 GHz. Antennas were designed and simulated for line-of-sight MIMO scenarios. An envelope correlation coefficient below 0.0356 was maintained for both designs. 2D SISO beam steering was also simulated. Achievable data rates were estimated from the antenna parameters, and the effect of interference was evaluated. Scan loss was mitigated for the two antenna rows within the focal region. A conformal transmitarray was designed, using 1-bit unit cells based on crossed-slots. A unit cell placement rule was proposed to reduce the number of electronically reconfigurable cells by 59%. A measured gain of 12.5 dBi and a simulated total efficiency of 75% were obtained at boresight and the maximum steering angle of 53°. By combining reconfigurable lenses with phased arrays, the focusing directivity is able to mitigate scan loss.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors :
NameEmailORCID
Hill, Timothy A.https://orcid.org/0000-0001-9925-8498
Date : 28 February 2020
Funders : EPSRC, 5G Innovation Centre (5GIC) HEFEC
DOI : 10.15126/thesis.00853272
Grant Title : Millimeter-wave Antennas and Components for Future Mobile Broadband Networks (MILLIBAN)
Copyright Disclaimer : In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of the University of Surrey's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink.
Contributors :
ContributionNameEmailORCID
http://www.loc.gov/loc.terms/relators/THSBrown, Tim W. C.t.brown@surrey.ac.uk
http://www.loc.gov/loc.terms/relators/THSKhalily, Mohsenm.khalily@surrey.ac.ukhttps://orcid.org/0000-0003-1861-5428
http://www.loc.gov/loc.terms/relators/THSKelly, Jamesj.kelly@qmul.ac.uk
Uncontrolled Keywords : 5G, 6G, mmWave, Phased Arrays, Beam Steerable Antennas, Wide Scan, Base Station, Beamforming, Focusing Directivity
Related URLs :
Additional Information : Animation videos, produced in CST Microwave Studio, are attached as supplementary material to show the electromagnetic fields and current density for some of the antennas presented in the thesis. The following publications are associated with this work: T. A. Hill and J. R. Kelly, “28 GHz Taylor Feed Network for Sidelobe Level Reduction in 5G Phased Array Antennas," Microw. Opt. Tech. Lett., vol. 61, no. 1, pp. 37-43, Jan. 2019. T. A. Hill, J. R. Kelly, M. Khalily and T. W. C. Brown, “Cascaded Fresnel Lenses for Scan Loss Mitigation in Millimeter Wave Access Points”, IEEE Trans. Antennas Propag., 2020. (under review) T. A. Hill, J. R. Kelly, M. Khalily and T. W. C. Brown, “Conformal Transmitarray for Scan Loss Mitigation with Thinned Reconfiguration”, in 2019 13th European Conference on Antennas and Propagation (EuCAP), Krakow, Poland, April 2019. M. Khalily, S. Taheri, P. Xiao, F. Entezami, T. A. Hill, R. Tafazolli, “26 GHz Indoor Wideband Directional Channel Measurement and Analysis in LoS and NLoS Scenarios," in 2018 12th European Conference on Antennas and Propagation (EuCAP), London, April 2018.
Depositing User : Tim Hill
Date Deposited : 06 Mar 2020 16:18
Last Modified : 06 Mar 2020 16:19
URI: http://epubs.surrey.ac.uk/id/eprint/853272

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