| 1. |
- Bagheri, Alireza, et al.
(author)
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TX Beamforming EVM Performance of a 65 dBm-EIRP Slant-Polarized Gapwaveguide Phased Array at 28 GHz
- 2023
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In: 17th European Conference on Antennas and Propagation, EuCAP 2023.
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Conference paper (peer-reviewed)abstract
- The transmit error vector magnitude (EVM) performance measurements of a slant-polarized 28 GHz gapwaveguide-based phased array is analyzed in this paper. The performance is studied by using a large range of signals, with varied powers, symbol rates, and quadrature amplitude modulation (QAM) orders. The measurements have been conducted for four different scanning angles. A non-standardized over-the-air (OTA) link between the phased array and the receiver in a laboratory environment is used. The results show that the phased array antenna supports a 31 dB effective isotropic radiated power (EIRP) dynamic range at a maximum 2% EVM when transmitting a 64QAM modulated signal with 250 MS/s symbol rate at all scanning directions.
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| 2. |
- Fager, Hanna, 1983-
(author)
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Growth and Characterization of Amorphous Multicomponent Nitride Thin Films
- 2014
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Doctoral thesis (other academic/artistic)abstract
- This thesis explores deposition of amorphous thin films based on the two transition metal nitride systems, TiN and HfN. Additions of Si, Al and B have been investigated using three different deposition techniques: dc magnetron sputtering, cathodic arc evaporation, and high power impulse magnetron sputtering (HIPIMS). The effect of elemental composition, bonding structure, growth temperature, and low-energy ion bombardment during growth has been investigated and correlated to the resulting microstructure and mechanical properties of the films. The thermal stability has been investigated by annealing experiments.Deposition by cathodic arc evaporation yields dense and homogeneous coatings with essentially fully electron-diffraction amorphous structures with additions of either Al+Si, B+Si or B+Al+Si to TiN. The B-containing coatings have unusually few macroparticles. Annealing experiments show that Ti-Al-Si-N coatings have an age hardening behavior, which is not as clear for B-containing coatings. Compositional layering, due to rotation of the sample fixture during deposition, is present but not always visible in the as-deposited state. The layering acts as a template for renucleation during annealing. The coatings recrystallize by growth of TiN-rich domains.Amorphous growth by conventional dc magnetron sputtering is possible over a wide range of compositions for Ti-B-Si-N thin films. The Ti content in the films is reduced compared to the content in the sputtering target. Without Si, the films consist of a BN onion-like structure surrounding TiN nanograins. With additions of Si the films eventually grows fully amorphous. The growth temperature has only minor effect on the microstructure, due to the limited surface diffusion at the investigated temperature range (100-600 °C). Ion assisted growth leads to nanoscale densification of the films and improved mechanical properties.Ti-B-Si-N thin films are also deposited by a hybrid technique where dc magnetron sputtering is combined with HIPIMS. Here, the Ti:B ratio remains equal to the target composition. Films with low Si content are porous with TiN nanograins separated by BN-rich amorphous channels and have low hardness. Increasing Si contents yield fully electron-amorphous films with higher hardness.Finally, Hf-Al-Si-N single-layer and multilayer films are grown by dc magnetron sputtering from a single Hf-Al-Si target. Amorphous growth is achieved when the growth temperature was kept at its minimum. Low-energy substrate bias modulation is used to grow nanocomposite/nanocolumnar multilayers from the single Hf-Al-Si target, where the layers has essentially the same composition but different Si bonding structure, and different degree of crystallinity.
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| 3. |
- Fager, Hanna
(author)
-
Growth and Characterization of Amorphous TiAlSiN and HfAlSiN Thin Films
- 2012
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Licentiate thesis (other academic/artistic)abstract
- This Thesis explores amorphous transition metal nitrides for cutting tool applications. The aim is to extend the knowledge on amorphous nitride thin lms, to describe the growth process, and to explore ways of characterizing these novel complex materials.Thin lms of Ti-Al-Si-N and Hf-Al-Si-N were fabricated using industrial cathodic arc evaporation and magnetically-unbalanced reactive magnetron sputtering, respectively. The microstructure of the lms was studied using x-ray diraction (XRD) and transmission electron microscopy (TEM), while compositional analysis of the lms was performed by spectroscopic techniques (EDS, SIMS, and RBS). The mechanical properties were investigated by nanoindentation.The Ti-Al-Si-N lms were grown on cemented carbide substrates using Ti-Al-Si compound cathodes in an N2 atmosphere. High Al and Si concentrations in the lms (i.e., 12 at% Si and 18 at% Al) promote renucleation and result in x-ray amorphous lms. High resolution TEM (HRTEM) reveals isolated grains, ~2 nm in size, embedded in an amorphous matrix. Annealing experiments show that the lms are thermally stable up to 900 oC. They exhibit age hardening, with an increase in hardness from 21.9 GPa for as-deposited lms to 31.6 GPa at 1000 oC. At 1100 oC severe out-diusion of Co and W from the substrate occurs, and the lms recrystallize into c-TiN and w-AlN.The single layer Hf-Al-Si-N and multilayer Hf-Al-Si-N/HfN lms were grown on Si(001) substrates from a single Hf0:60Al0:20Si0:20 alloy target in an N2/Ar atmosphere. The composition and nanostructure of the lms was controlled during growth by independently varying the ion energy (Ei) and the ion-to-metal flux ratio (Ji=JMe). With Ji/JMe=8, the nanostructure and composition of the lms changes from x-ray amorphous with a Hf content of 0.6, to an amorphous matrix with encapsulated nanocrystals with 0.66≤Hf≤0.84, to nanocrystalline with 0.96≤Hf≤1.00, when increasing Ei from 15 to 65 eV. Varying Ji=JMe with Ei=13 eV yields electron-diraction amorphous lms at substrate temperatures of 100 oC. Hf-Al-Si-N/HfN multilayers with periods Λ=2-20 nm exhibit enhanced fracture toughness compared to polycrystalline VN, TiN, and Ti0:5Al0:5N reference samples; multilayer hardness values increase from 20 GPa with Λ=20 nm to 27 GPa with Λ=2 nm.̴
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| 4. |
- Fager, Hanna, et al.
(author)
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Growth and Properties of Amorphous Hf1−x−yAlxSiyN (0≤x≤0.2; 0≤y≤0.2) and a-Hf0.6Al0.2Si0.2N/nc-HfN Multilayers by DC Reactive Magnetron Sputtering from a Single Hf0.60Al0.20Si0.20 Target
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Other publication (other academic/artistic)abstract
- Amorphous (a) and nanocrystalline (nc) Hf1−x−yAlxSiyN and multilayer a-Hf0.6Al0.2Si0.2N/nc-HfN films are grown on Si(001) at temperatures Ts = 100-450 ◦C using ultrahigh vacuum magnetically-unbalanced reactive magnetron sputtering from a single Hf0.60Al0.20Si0.20 target in a 5%-N2/Ar atmosphere at a total pressure of 20 mTorr (2.67 Pa). The composition and nanostructure of Hf1−x−yAlxSiyN is controlled during growth by independently varying the ion energy (Ei) and the ion-to-metal flux ratio (Ji/JMe) incident at the film surface. With Ji/JMe = 8, the composition and nanostructure of the films ranges from x-ray amorphous with 1-x-y = 0.60 at Ei = 15 eV, to an amorphous matrix with encapsulated nanocrystals with 1-x-y = 0.66-0.84 at Ei = 25-35 eV, to nanocrystalline with 1-x-y = 0.96-1.00 at Ei = 45-65 eV. Varying Ji/JMe with Ei = 13 eV yields amorphous alloy films at Ts = 100 ◦C. a-Hf0.6Al0.6Si0.6N/nc-HfN multilayers with periods Λ = 2-20 nm exhibit enhanced fracture toughness compared to polycrystalline VN, TiN, and Ti0.5Al0.5N reference samples; multilayer hardness values increase monotonically from 20 GPa with Λ = 20 nm to 27 GPa with Λ = 2 nm.
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| 5. |
- Fager, Hanna, et al.
(author)
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Growth and properties of amorphous Ti-B-Si-N thin films deposited by hybrid HIPIMS/DC-magnetron co-sputtering from TiB2 and Si targets
- 2014
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In: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 259, s. 442-447
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Journal article (peer-reviewed)abstract
- Amorphous nitrides are explored for their homogenous structure and potential use as wear-resistant coatings, beyond their much studied nano-and microcrystalline counterparts. (TiB2)1−xSixNy thin films were deposited on Si(001) substrates by a hybrid technique of high power impulse magnetron sputtering (HIPIMS) combined with dc magnetron sputtering (DCMS) using TiB2 and Si targets in a N2/Ar atmosphere. By varying the sputtering dc power to the Si target from 200 to 2000 W while keeping the average power to the TiB2-target, operated in HIPIMS mode, constant at 4000 W, the Si content in the films increased gradually from x=0.01 to x=0.43. The influence of the Si content on the microstructure, phase constituents, and mechanical properties were systematically investigated. The results show that the microstructure of as-deposited (TiB2)1−xSixNy films changes from nanocrystalline with 2-4 nm TiN grains for x=0.01 to fully electron diffraction amorphous for x=0.22. With increasing Si content, the hardness of the films increases from 8.5 GPa with x=0.01 to 17.2 GPa with x=0.43.
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| 6. |
- Fager, Hanna, et al.
(author)
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Growth of Hard Amorphous Ti-Al-Si-N Thin Films by Cathodic Arc Evaporation
- 2013
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 235:25, s. 376-385
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Journal article (peer-reviewed)abstract
- Ti(1−x−y)AlxSiyNz (0.02≤x≤0.46, 0.02≤y≤0.28, and 1.08≤z≤1.29) thin films were grown on cemented carbide substrates in an industrial scale cathodic arc evaporation system using Ti-Al-Si compound cathodes in a N2 atmosphere. The microstructure of the as-deposited films changes from nanocrystalline to amorphous by addition of Al and Si to TiN. Upon incorporation of 12 at% Si and 18 at% Al, the films assume an x-ray amorphous state. Post-deposition anneals show that the films are thermally stable up to 900 ◦C. The films exhibit age hardening up to 1000 ◦C with an increase in hardness from 21.9 GPa for as-deposited films to 31.6 GPa at 1000 ◦C. At 1100 ◦C severe out-diffusion of Co and W from the substrate occur, and the films recrystallize into c-TiN and w-AlN.
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| 7. |
- Fager, Hanna, et al.
(author)
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Hf-Al-Si-N multilayers deposited by reactive magnetron sputtering from a single Hf0.6Al0.2Si0.2 target using high-flux, low-energy modulated substrate bias : film growth and properties
- 2014
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Other publication (other academic/artistic)abstract
- Hf1−x−yAlxSiyN (0≤x≤0.14, 0≤y≤0.13) single layers and multilayer films are grown on Si(001) at a substrate temperature Ts=250 °C using ultrahigh vacuum magnetically-unbalanced reactive magnetron sputtering from a single Hf0.6Al0.2Si0.2 target in a 5%-N2/Ar atmosphere at a total pressure of 20 mTorr (2.67 Pa). The composition and nanostructure of Hf1−x−yAlxSiyN is controlled during growth by varying the ion energy (Ei) of the ions incident at the film surface, keeping the ion-to-metal flux ratio (Ji/JMe) constant at 8. By sequentially switching Ei between 10 and 40 eV, Hf0.77Al0.10Si0.13N/Hf0.78Al0.14Si0.08N multilayers with bilayer periods Λ = 2-20 nm are grown, in which the Si2p bonding state changes from predominantly Si-Si bonds for films grown at Ei = 10 eV, to mainly Si-N bonds at Ei = 40 eV. Multilayer hardness values increase monotonically from 20 GPa with Λ = 20 nm to 27 GPa with Λ = 2 nm, while multilayer fracture toughness increases with increasing Λ. Multilayers with Λ = 10 nm have the optimized property combination of being bothrelatively hard, H∼24 GPa, and fracture tough.
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| 8. |
- Fager, Hanna, 1983-, et al.
(author)
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Kvalitetskontroll av vägmarkering i Norden : Förutsättningar för ett gemensamt regelverk
- 2023
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Reports (other academic/artistic)abstract
- De statliga väghållarna i Danmark, Finland, Island, Norge och Sverige har under en längre tid diskuterat om det skulle vara möjligt att införa ett gemensamt kontrollsystem för leverans-, garanti och tillståndskontroll hos vägmarkeringar.I dagsläget utförs kontrollen med stora variationer både mellan länder och mellan olika regioner i samma land, vilket kan leda till regionala kvalitetsskillnader och snedvriden konkurrens. Utöver detta finns ett flertal svårigheter i hur mätning och kontroll ska genomföras på ett likvärdigt sätt av olika utförare.Syftet med detta projekt har varit att undersöka förutsättningarna för ett gemensamt system för kvalitetskontroll för vägmarkeringar i Norden. Projektet har genomförts som en förstudie där uppdraget har varit att sammanställa och jämföra de nationella regelverken samt föra dialog med respektive väghållare och representanter för branschen för att kunna identifiera vad som fungerar bra och vad som behöver utvecklas i nuvarande kontrollsystem.Informationen i rapporten baserar sig på den dokumentation kring krav i kontrakt och regelverk som vi fått från väghållarna i Danmark, Finland, Island, Sverige och Norge.Projektet har visat på stora svårigheter att sammanfatta detaljerna i regelverken i de nordiska länderna eftersom det är många olika typer av dokument inblandade och många detaljer står i kontraktshandlingarna för varje enskild upphandling och varierar från år till år.Slutsatsen är att det trots stora utmaningar bedöms vara fullt möjligt att införa ett gemensamt system. Detta kräver dock en stor insats från väghållarsidan och att det finns förankring hos respektive organisation för ett sådant arbete.
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| 9. |
- Fager, Hanna, et al.
(author)
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Low-temperature growth of dense and hard Ti0.41Al0.51Ta0.08N films via hybrid HIPIMS/DC magnetron co-sputtering with synchronized metal-ion irradiation
- 2017
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In: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 121:17
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Journal article (peer-reviewed)abstract
- Hard Ti1-xAlxN thin films are of importance for metal-cutting applications. The hardness, thermal stability, and oxidation resistance of these coatings can be further enhanced by alloying with TaN. We use a hybrid high-power pulsed and dc magnetron co-sputtering (HIPIMS/DCMS) technique to grow dense and hard Ti0.41Al0.51Ta0.08N alloys without external heating (T-s amp;lt; 150 degrees C). Separate Ti and Al targets operating in the DCMS mode maintain a deposition rate of similar to 50 nm/min, while irradiation of the growing film by heavy Ta+/Ta2+ ions from the HIPIMS-powered Ta target, using dc bias synchronized to the metal-ion-rich part of each HIPIMS pulse, provides effective near-surface atomic mixing resulting in densification. The substrate is maintained at floating potential between the short bias pulses to minimize Ar+ bombardment, which typically leads to high compressive stress. Transmission and scanning electron microscopy analyses reveal dramatic differences in the microstructure of the co-sputtered HIPIMS/DCMS films (Ta-HIPIMS) compared to films with the same composition grown at floating potential with all targets in the DCMS mode (Ta-DCMS). The Ta-DCMS alloy films are only similar to 70% dense due to both inter-and intra-columnar porosity. In contrast, the Ta-HIPIMS layers exhibit no inter-columnar porosity and are essentially fully dense. The mechanical properties of Ta-HIPIMS films are significantly improved with hardness and elastic modulus values of 28.0 and 328 GPa compared to 15.3 and 289 GPa for reference Ta-DCMS films. Published by AIP Publishing.
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| 10. |
- Fager, Hanna, et al.
(author)
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Novel hard, tough HfAlSiN multilayers, defined by alternating Si bond structure, deposited using modulated high-flux, low-energy ion irradiation of the growing film
- 2015
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In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : A V S AMER INST PHYSICS. - 0734-2101 .- 1520-8559. ; 33:5, s. 05E103-1-05E103-9
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Journal article (peer-reviewed)abstract
- Hf1-x-yAlxSiyN (0 less than= x less than= 0.14, 0 less than= y less than= 0.12) single layer and multilayer films are grown on Si(001) at 250 degrees C using ultrahigh vacuum magnetically unbalanced reactive magnetron sputtering from a single Hf0.6Al0.2Si0.2 target in mixed 5%-N-2/Ar atmospheres at a total pressure of 20 mTorr (2.67 Pa). The composition and nanostructure of Hf1-x-yAlxSiyN films are controlled by varying the energy Ei of the ions incident at the film growth surface while maintaining the ion-to-metal flux ratio constant at eight. Switching E-i between 10 and 40 eV allows the growth of Hf0.78Al0.10Si0.12N/Hf0.78Al0.14Si0.08N multilayers with similar layer compositions, but in which the Si bonding state changes from predominantly Si-Si/Si-Hf for films grown with E-i = 10 eV, to primarily Si-N with E-i = 40 eV. Multilayer hardness values, which vary inversely with bilayer period Lambda, range from 20 GPa with Lambda = 20 nm to 27 GPa with Lambda = 2 nm, while fracture toughness increases directly with Lambda. Multilayers with Lambda = 10nm combine relatively high hardness, H similar to 24GPa, with good fracture toughness. (C) 2015 American Vacuum Society.
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