| 1. |
- Meyer, E., et al.
(författare)
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The state of the art in beyond 5G distributed massive multiple-input multiple-output communication system solutions
- 2022
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Ingår i: Open Research Europe. - : F1000 Research Ltd. - 2732-5121. ; 2
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Forskningsöversikt (refereegranskat)abstract
- Beyond fifth generation (5G) communication systems aim towards data rates in the tera bits per second range, with improved and flexible coverage options, introducing many new technological challenges in the fields of network architecture, signal pro- cessing, and radio frequency front-ends. One option is to move towards cell-free, or distributed massive Multiple-Input Multiple-Output (MIMO) network architectures and highly integrated front-end solutions. This paper presents an outlook on be- yond 5G distributed massive MIMO communication systems, the signal processing, characterisation and simulation challenges, and an overview of the state of the art in millimetre wave antennas and electronics.
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| 3. |
- ÖZEN, MUSTAFA, 1984, et al.
(författare)
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Wideband and efficient watt-level SiGe BiCMOS switching mode power amplifier using continuous class-E modes theory
- 2014
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Ingår i: Digest of Papers - IEEE Radio Frequency Integrated Circuits Symposium. - 1529-2517. - 9781479938629 ; , s. 243-246
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Konferensbidrag (refereegranskat)abstract
- In this paper, a generic, wide-band switch mode power amplifier (SMPA) design approach is developed based on the continuous class-E modes theory. A watt level, 1.3-2.2 GHz SiGe BiCMOS class-E SMPA is realized for experimental verification. The prototype provides collector efficiencies higher than 70% and output power levels higher than 29 dBm across 1.3-2.2 GHz band, fully confirming the validity of the proposed design approach.
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| 7. |
- Fager, Hanna, et al.
(författare)
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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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Annan publikation (övrigt vetenskapligt/konstnärligt)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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| 9. |
- Wieckowski, A., et al.
(författare)
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Efficiency optimization for phase controlled multi-source microwave oven
- 2014
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Ingår i: International Journal of Applied Electromagnetics and Mechanics. - : IOS Press. - 1383-5416 .- 1875-8800. ; 44:2, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- A solid-state microwave generators system is considered as an alternative to the magnetron, in order to inject electromagnetic energy into the cavity of a microwave oven for domestic use. Over current devices, the use of solid state technology allows one to control the frequency and phase of the electromagnetic field generated. Considering a simplified cavity with 2 solid state sources, the influence of the electrical parameters on maximum efficiency obtainable in the process of microwave heating is investigated. By varying the frequency, different values of optimal phases and different values of maximum efficiency are detected. Moreover, the procedure is repeated with varying the position of one source port and the influence of geometry on the system performance is evaluated. Our results demonstrate that the ability to control the electrical quantities of a microwave heating process makes it possible to obtain better results in terms of energy efficiency over the current poorly controllable systems.
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| 10. |
- ÖZEN, MUSTAFA, 1984, et al.
(författare)
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A Generalized Combiner Synthesis Technique for Class-E Outphasing Transmitters
- 2017
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Ingår i: IEEE Transactions on Circuits and Systems I: Regular Papers. - : Institute of Electrical and Electronics Engineers (IEEE). - 1549-8328 .- 1558-0806. ; 64:5, s. 1126-1139
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a generic combiner design technique is developed for class-E outphasing transmitters. The design procedure starts with calculation of the combiner network parameters that guarantee high efficiency switch mode operation of the PAs in each branch. Recently developed continuous class-E modes theory is then utilized to create an additional degree of freedom for calculation of the combiner network parameters. This additional degree of freedom along with duty cycle control provides an important possibility for achieving high average efficiency over a large bandwidth. A CMOS-GaN outphasing transmitter prototype is realized for experimental verification. The prototype provides drain efficiencies higher than 60% at 6 dB back-off across 750-1050 MHz band. Further, the peak output power remains nearly flat versus frequency, where the variation across the band is +/- 0.18 dB around 44 dBm.
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