| 1. |
- Björkqvist, Oskar, et al.
(författare)
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Additive manufactured dielectric Gutman lens
- 2019
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology. - 0013-5194 .- 1350-911X. ; 55:25, s. 1318-1320
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Tidskriftsartikel (refereegranskat)abstract
- In this Letter, the design of a 3D printed fully dielectric Gutman lens is presented. The authors demonstrate the feasibility of using highly accessible and cheap additive manufacturing technology to produce a compact and high performing antenna lens. The lens is designed to operate at Ku band and utilises a flat feed surface that approximates the focal sphere. The flat feed surface allows for beam steering that requires only translational movement of the feed. The lens has a measured realised gain of 20 dBi with 3 dB scan loss at +45°. The lens finds applications in systems that require high gain antennas, such as the new generation of satellite and 5G communications and radar technology.
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| 2. |
- Algaba-Brazalez, A., et al.
(författare)
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Compact Polarization Transformation in a Geodesic Luneburg Lens Antenna
- 2021
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Ingår i: 2021 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, APS/URSI 2021 - Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 1992-1993
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Konferensbidrag (refereegranskat)abstract
- This paper describes the design of a compact polarizer that rotates the linear polarization of a fully metallic geodesic Luneburg lens antenna for applications requiring polarization diversity. The polarization rotation is achieved by loading the radiating aperture of the antenna with two metallic screens. The integrated antenna operates in the Ka-band, from 25 to 31 GHz, showing around 20% bandwidth with S11 below -10 dB, and a scanning range of 100°.
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| 3. |
- Algaba-Brazalez, Astrid, et al.
(författare)
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Crossover level improvement between beams in a geodesic lens antenna based on a generalized Luneburg lens
- 2022
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Ingår i: 2022 16th European Conference on Antennas and Propagation (EuCAP). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a geodesic generalized Luneburg lens operating in the 60-GHz band, from 57 to 67 GHz, designed with the goal to improve the crossover level between beams with respect to previously reported fully metallic Luneburg lenses, while providing highly directive beams and wide scanning coverage. We have combined the use of a generalized Luneburg lens and the design of a compact feeding type based on ridge waveguide in order to achieve an optimum crossover level between beams keeping in mind manufacturing simplicity. The numerical evaluation of the final integrated lens design including 21 ridge waveguide feeding ports shows a vertical bar S-11 vertical bar parameter below -13.6 dB over the frequency band of interest, a scanning range of +/- 52 degrees, a realized gain higher than 19 dBi over the whole operating bandwidth, and a crossover level value between -3.5 dB and -4.2 dB from the lowest to the highest frequency of operation.
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| 4. |
- Ansari, Maral, et al.
(författare)
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A Lightweight Metalized-Insert Luneburg Lens
- 2023
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Ingår i: 2023 17TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, EUCAP. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In this paper, a lightweight spherical Luneburg lens with high performance is introduced for use in the frequency range 1 (FR1). The continuously varying refractive index profile of the lens is implemented using a quasi-isotropic partially metalized periodic structure. Much of the lens volume is made of foam, so the design is lightweight, making it applicable for low-band microwave frequency communication systems and, more specifically, 5G communications in FR1. The periodic structure allows a simple and low-cost layered construction with a quasi-isotropic response. This approach improves the scanning performance of the lens in all angular directions when compared to equivalent lens designs previously reported. Such a structure is an ideal candidate for high-gain multi-beam communication systems.
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| 5. |
- Börjesson Axén, Jenny, et al.
(författare)
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Short-Term Impact of AC Harmonics on Aging of NiMH Batteries for Grid Storage Applications
- 2021
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- Batteries in energy storage systems are exposed to electrical noise, such as alternating current (AC) harmonics. While there have been many studies investigating whether Lithium-ion batteries are affected by AC harmonics, such studies on Nickel Metal Hydride (NiMH) batteries are scarce. In this study a 10 Ah, 12 V NiMH battery was tested with three different harmonic current frequency overlays during a single charge/discharge cycle: 50 Hz, 100 Hz, and 1000 Hz. No effect on battery internal temperature or gas pressure was found, indicating that NiMH battery aging is not affected by the tested harmonic AC frequencies. This can reduce the cost of energy storage systems, as no extra filters are needed to safeguard the batteries. Instead, the capacitive properties of the batteries give the possibility to use the battery bank itself as a high pass filter, further reducing system complexity and cost.
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| 6. |
- Castillo Tapia, Pilar, et al.
(författare)
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Azimuth and Elevation Scanning with Stacked Modulated Geodesic Luneburg Lenses
- 2022
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Ingår i: 2022 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 5-6
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Konferensbidrag (refereegranskat)abstract
- Here, we propose a modulated geodesic lens antenna array in E-band (56-62 GHz), which has scanning abilities in both azimuth and elevation. The array consists of four lens antenna elements, and each lens antenna produces 13 independent beams that cover 110 degrees in the H-plane with scan losses below 1 dB. The array is fed with a 1:4 power divider comprising three phase shifters to scan in the E-plane. The distance between lenses in the E-plane is 0.7 wavelengths at 60 GHz. The E-plane coverage is 60 degrees with scan losses around -2.2 dB. The maximum realized gain varies from 20.8 to 24.1 dB across the frequency band.
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| 7. |
- Castillo Tapia, Pilar, et al.
(författare)
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Two-Dimensional Beam Steering Using a Stacked Modulated Geodesic Luneburg Lens Array Antenna for 5G and Beyond
- 2023
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Ingår i: IEEE Transactions on Antennas and Propagation. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-926X .- 1558-2221. ; 71:1, s. 487-496
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Tidskriftsartikel (refereegranskat)abstract
- Antennas for future communication systems are required to be highly directive and steerable to compensate for the high path loss in the millimeter-wave band. In this work, we propose a linear array of modulated geodesic Luneburg lens (the so-called water drop lens) antennas operating at 56-62 GHz. The lens array antenna features 2-D beam scanning with low structural complexity. The lenses are fully metallic and implemented in parallel plate waveguides (PPWs), meaning that they are highly efficient. Each lens is fed with 13 rectangular waveguides surrounded by glide-symmetric holes to suppress leakage. The lenses provide 110? beam coverage in the H-plane with scan losses below 1 dB. In order to scan in the E-plane, we use a feeding network based on a 1:4 power divider and three phase shifters. In this configuration, the array can scan 60? in the E-plane, albeit with higher scanning losses than in the H-plane. The lens array is manufactured and a good agreement between simulated and experimental results is obtained.
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| 8. |
- Chen, Qiao, et al.
(författare)
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Glide-Symmetric Holey Leaky-Wave Antenna With Low Dispersion for 60 GHz Point-to-Point Communications
- 2020
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Ingår i: IEEE Transactions on Antennas and Propagation. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-926X .- 1558-2221. ; 68:3, s. 1925-1936
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Tidskriftsartikel (refereegranskat)abstract
- In this article, two novel efficient leaky-wave antennas (LWAs) with stable radiation patterns operating in the 60 GHz band are proposed. The LWAs are implemented in groove-gap waveguide (GGW) technology. To mitigate the beam squint due to the dispersive nature of LWAs, complementary-dispersive prisms are coupled to the LWA radiation aperture. The antennas are implemented in fully metallic purely holey periodic structures, resulting in a more cost-effective and robust manufacturing process compared to previously reported pin-based structures. Two prisms are proposed, one with mirror symmetry and one with glide symmetry. When the prism possesses a glide symmetry, much fewer holes are required while maintaining a similar performance, which even further decreases the fabrication costs. The complex propagation constant is optimized for low sidelobe levels (SLLs) with tailored hole diameters and waveguide dimensions, thus for the first time demonstrating the capability of using glide-symmetric holes to control the leakage rate. Two prototypes with mirror- and glide-symmetric prisms are theoretically synthesized and validated by the simulated and experimental results. A frequency bandwidth of 11% is achieved for both prototypes with the beam squint within +/- 0.9 degrees (mirror) and +/- 1.7 degrees (glide), SLLs below -15 dB (mirror) and -13 dB (glide), total efficiency almost 90%, and realized gain of 17 +/- 0.5 dB at a fixed observing angle. The developed antennas are intended for mm-wave point-to-point communications.
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| 9. |
- Chen, Qiao, et al.
(författare)
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Prism-based Leaky-Lens Antennas at 60 GHz for 5G Point-to-Point Communication Links
- 2020
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Ingår i: 2020 14TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP 2020). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- Two cost-effective implementations of a leaky-lens antenna at 60 GHz are proposed for high-throughput 5G communication links. The leaky-wave feed is realized in gap-waveguide technology, where the radiation from the slit is controlled with glide-symmetric holes. The beam-squint of the leaky-wave radiation is mitigated, owing to the coupling of a complementary dispersive prism. Here, two prisms are implemented, one with glide-symmetric holes, and another with substrate-integrated holes (SIHs), both integrated in parallel plates with the leaky wave feeding. Thanks to glide symmetry, better control of the leakage rate, lower costs, and better tolerance to manufacturing are achieved in comparison with the non-glide holey counterpart. In addition, the SIH-based design exhibits a substantially enhanced bandwidth with even better robustness. In the analysis of the leaky-wave feed, more accuracy and reduced computational time is achieved by using a multi-mode method. Both antennas show stable radiation patterns, featuring high efficiency, high gain, and low side lobe levels.
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| 10. |
- Clendinning, Sarah, et al.
(författare)
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Ray Tracing Model for Non-Rotationally Symmetric Geodesic Lens Antennas with Full Beam Scanning Range in the Azimuthal Plane
- 2023
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Ingår i: The 13th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2023. - : META Conference. ; , s. 1050-1051
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Konferensbidrag (refereegranskat)abstract
- This presentation discusses a ray tracing model developed to determine the radiation pattern of geodesic lens antennas with non-rotationally symmetric footprints, where the geometry of the lens is defined using spline functions. The shape of this footprint and lens height profile can be modified by changing parameters in the defined functions. The code features a significant modification to work previously published by the authors to account for the non-rotationally symmetric design. The model runs significantly faster than commercially available software.
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