| 1. |
- Behmanesh, Baktash, et al.
(author)
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An 88% fractional bandwidth reconfigurable power amplifier for NB-IoT and LTE-M in 22 nm CMOS FDSOI
- 2022
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In: 2022 IEEE Nordic Circuits and Systems Conference (NorCAS). - 9798350345513 - 9798350345506
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Conference paper (peer-reviewed)abstract
- A wideband power amplifier (PA), with 88% fractional bandwidth operating in the 700 MHz to 1.8 GHz range, which covers most of the standardized narrowband internet-of-things (NB-IoT) and LTE-M bands, is fully integrated in 22 nm CMOS FDSOI. A single-stage differential amplifier core, combined with an on-chip balun, realizes a single-ended output. A stacked circuit architecture, with 3.3 V LDMOS transistors as output devices and thin-oxide flipped-well transistors as the input common-source (CS) stage, enable a wide bandwidth and reliable operation at a supply voltage of 2.55 V. Capacitor banks with stacked thin-oxide transistor switches tune the PA frequency characteristics over the wide frequency range. The PA delivers a saturated output power (P sat ) of up to +24.4 dBm with up to 45% power-added efficiency, which is compliant with the current 3GPP standard for NB-IoT and LTE-M. The maximum power-gain varies between 30.7 dB and 29.2 dB over the whole frequency range. The PA core circuit occupies 0.32 mm 2 of silicon area, of which 0.2 mm 2 is occupied by the low loss balun.
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| 2. |
- Chen, Peng, et al.
(author)
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Analysis and design of an 1-20 GHz track and hold circuit
- 2021
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In: 2021 IEEE International Symposium on Circuits and Systems, ISCAS 2021 - Proceedings. - 0271-4310. - 9781728192017 ; 2021-May
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Conference paper (peer-reviewed)abstract
- This work analyzes the nonlinear effects in the track and hold circuit applied in high-speed ADCs or RF sampling receiver (RX) front-ends. Non-ideal effects inside the main sampling NMOS switch are studied. Parasitic varactor and sampling on-resistance modulation effects are analyzed through frequency domain Volterra series and the EKV MOS transistor model. Polynomial curve fitting is applied showing that the on-resistance modulation dominates. Finally, a novel bootstrap circuit is proposed with a fast settling time and high bootstrap voltage in a 22 nm FD-SOI CMOS technology, with its settling time analyzed using the Elmore delay model.
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| 3. |
- Gannedahl, Rikard, et al.
(author)
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Active and Passive Integrated Filters for Multi-GHz 6G Baseband Applications
- 2023
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In: 2023 Asia-Pacific Microwave Conference, APMC 2023. - 9781665494182 ; , s. 524-526
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Conference paper (peer-reviewed)abstract
- This paper presents the design and comparison of an active Gm-C and a passive baseband filter for 6G applications. Both presented circuits are 5th-order differential low-pass filters with 3-dB cut-off frequencies of 4.9 and 4.7 GHz, respectively, implemented in a 22 nm FD-SOI CMOS technology. The active filter uses back-gate tuning to optimize the transfer function, and achieves a measured in-band IIP3 between -1.0 and -9.1 dBVp, out-of-band IIP3 between 1.0 and 15 dBVp, and input-referred noise of 6.55 nV / √Hz, while consuming 19.9 mW from a 0.8 V supply and occupying 0.05 mm2 core chip area. By utilizing mutual inductance, the footprint of the passive filter is minimized, occupying only 0.07
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| 4. |
- Gannedahl, Rikard, et al.
(author)
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An LO phase shifter with frequency tripling and phase detection in 28 nm FD-SOI CMOS for mm-wave 5G transceivers
- 2023
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In: Analog Integrated Circuits and Signal Processing. - : Springer Science and Business Media LLC. - 0925-1030 .- 1573-1979. ; 114:1, s. 1-11
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Journal article (peer-reviewed)abstract
- This paper presents an LO phase shifter with frequency tripling for 28-GHz 5G transceivers. The phase shifting and frequency tripling are achieved using an injection-locked oscillator and injection-locked frequency tripler, respectively. A phase detector based on third harmonic mixing is also implemented and is used to detect the applied phase shift, supporting automatic calibration of the phase shifter. Additionally, an algorithm to automatically tune the oscillators to their respective locking frequency is presented. To test the phase shifter, a 24–30-GHz sliding-IF receiver is implemented. Simulations show that a > 360∘ tuning range over the full 24–30 GHz span is achieved, with a gain variation of 0.11 dB or less, and that the phase detector has an rms phase error of < 2.5∘. The circuit is implemented in a 28nm FD-SOI CMOS process and the entire chip measures 1080 μ m × 1080 μ m , including pads, and consumes 27–29 mW from a 1 V supply.
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| 5. |
- Ghanavati Nejad, Tayebeh, et al.
(author)
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An ultra-low power high-precision logarithmic-curvature compensated all-CMOS voltage reference in 65 nm CMOS
- 2021
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In: Analog Integrated Circuits and Signal Processing. - : Springer Science and Business Media LLC. - 0925-1030 .- 1573-1979. ; 107:2, s. 319-330
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Journal article (peer-reviewed)abstract
- In this paper, a low-complexity resistorless high-precision sub-1 V MOSFET-only voltage reference is presented. To obtain an accurate output, a curvature-compensation technique is used, canceling its logarithmic temperature dependence regardless of the value of the mobility temperature exponent (γ). The circuit is realized in 65 nm CMOS technology and yields an output voltage of 574 mV, a temperature coefficient of 3.5 ppm∘C in the range of − 50 to 150 °C, a power supply rejection ratio (PSRR) of − 103 dB at 100 Hz, a line sensitivity of 6μVV in the supply voltage range of 1.3–3 V, a power dissipation of 650nW at 1.3 V supply, and an output noise of 1.7 μV/Hz at 100 Hz. The total active area of the design is 0.03 mm2. This voltage reference is suitable for low-power low-voltage applications which also require high precision.
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| 6. |
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| 7. |
- Solans, Virginie, et al.
(author)
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Evaluating Peak Area Uncertainties in Connection to Passive Gamma Measurements of Spent Nuclear Fuel
- 2021
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In: Proceedings. - 9789295064355
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Conference paper (peer-reviewed)abstract
- In many countries, spent nuclear fuel is planned to be stored in a geological repository. Before the final encapsulation, safety parameters such as decay heat, criticality, and dose rate need to be ensured. A gamma scan of the spent nuclear fuel assemblies in the pool can extract valuable information needed to verify or update the declared values before the encapsulation. Gamma scans can be used to esti mate values such as burnup, cooling time, or initial enrichment [1], but also decay heat [2]. This paper presents results from a fullenergy peak area evaluation study of experimental gammaray spectra acquired from measurements using a highpurity germanium detector on 47 spent nuclear fuel assemblies from Sweden in 2016 and 2019. The assemblies chosen are UO2 fuel and represent a large span in cooling time, burnup, and initial enrichment [3]. The gamma spectra were acquired in the spent fuel pool of the Clab facility. As part of the measurement analysis, one wishes to determine the fullenergy net peak areas associated with selected fission products. This work presents results obtained using different methods to evaluate the fullenergy peak areas, including the use of different background estimations.In the determination of important safety parameters using gamma spectroscopy, it is crucial to consider uncertainties originating in the peak area analysis. The un certainty from the fullenergy peak area without the background has been evaluated and compared between the different models.
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| 8. |
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| 9. |
- Solans, Virginie, et al.
(author)
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Spent Nuclear Fuel passive gamma analysis and reproducibility : Application to SKB-50 assemblies
- 2023
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In: Annals of Nuclear Energy. - : Elsevier. - 0306-4549 .- 1873-2100. ; 192
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Journal article (peer-reviewed)abstract
- This work studies the reproducibility of passive gamma spectroscopy measurements for spent nuclear fuels (SNFs). The fifty assemblies used for this study span over a variety of initial enrichments, burnups, and cooling times. These SNFs have been measured in two different gamma axial measurement campaigns. The net peak counts are determined for Cs-137, Eu-154 and Cs-134. Furthermore, a sensitivity analysis of the relative position of the SNF and the detector is performed. Most importantly, this work describes a methodology using an intrinsic self-calibration procedure that can be used to compare the relative activities of the radionuclides without the need for detailed knowledge about the measurement set-up and its properties. The reproducibility of the Cs-137 net peak count rate ranges between 2% and 4%. Systematic reproducibility of the ratio of Eu-154 and Cs-134 to Cs-137 is between 0,4% - 5 % using the intrinsic self-calibration method.
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| 10. |
- Tataria, Harsh, et al.
(author)
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6G Wireless Systems: Vision, Requirements, Challenges, Insights, and Opportunities
- 2021
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In: Proceedings of the IEEE. - 0018-9219. ; 109:7, s. 1166-1199
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Journal article (peer-reviewed)abstract
- Mobile communications have been undergoing a generational change every ten years or so. However, the time difference between the so-called "G's" is also decreasing. While fifth-generation (5G) systems are becoming a commercial reality, there is already significant interest in systems beyond 5G, which we refer to as the sixth-generation (6G) of wireless systems. In contrast to the already published papers on the topic, we take a top-down approach to 6G. More precisely, we present a holistic discussion of 6G systems beginning with lifestyle and societal changes driving the need for next generation networks. This is followed by a discussion into the technical requirements needed to enable 6G applications, based on which we dissect key challenges, as well as possibilities for practically realizable system solutions across all layers of the Open Systems Interconnection stack (i.e., from applications to the physical layer). Since many of the 6G applications will need access to an order-of-magnitude more spectrum, utilization of frequencies between 100 GHz and 1 THz becomes of paramount importance. As such, the 6G eco-system will feature a diverse range of frequency bands, ranging from below 6 GHz up to 1 THz. We comprehensively characterize the limitations that must be overcome to realize working systems in these bands; and provide a unique perspective on the physical, as well as higher layer challenges relating to the design of next generation core networks, new modulation and coding methods, novel multiple access techniques, antenna arrays, wave propagation, radio-frequency transceiver design, as well as real-time signal processing. We rigorously discuss the fundamental changes required in the core networks of the future, such as the redesign or significant reduction of the transport architecture that serves as a major source of latency for time-sensitive applications. This is in sharp contrast to the present hierarchical network architectures, which are not suitable to realize many of the anticipated 6G services. While evaluating the strengths and weaknesses of key candidate 6G technologies, we differentiate what may be practically achievable over the next decade, relative to what is possible in theory. Keeping this in mind, we present concrete research challenges for each of the discussed system aspects, providing inspiration for what follows.
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