| 1. |
- Axelsson, Olle, 1986, et al.
(author)
-
Impact of Trapping Effects on the Recovery Time of GaN Based Low Noise
- 2016
-
In: IEEE Microwave and Wireless Components Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-1764 .- 1531-1309. ; 26:1, s. 31-33
-
Journal article (peer-reviewed)abstract
- This study investigates recovery time of the gain of AlGaN/GaN HEMT based low noise amplifiers (LNA) after an input overdrive pulse. Three LNAs, fabricated in two commercial MMIC processes and a Chalmers in-house process, are evaluated. The Chalmers process has an unintentionally doped buffer instead of the intentional Fe doping of the buffer which is standard in commercial GaN HEMT technologies. It is shown that the LNAs from the two commercial processes experience a severe drop in gain after input overdrive pulses higher than 28 dBm, recovering over a duration of around 20 ms. In contrast the LNA fabricated in-house at Chalmers experienced no visible effects up to an input power of 33 dBm. These results have impact for radar and electronic warfare receivers, which need to be operational immediately after an overdrive pulse. The long time constants suggest that these effects are due to trapping in the transistors with the Fe doped buffer playing an important role.
|
|
| 2. |
- Billström, Niklas, et al.
(author)
-
High performance GaN front-end MMICs
- 2011
-
In: 14th European Microwave Week 2011: "Wave to the Future", EuMW 2011 - 6th European Microwave Integrated Circuit Conference, EuMIC 2011, Manchester, 10 October through 11 October 2011. - 9782874870231 ; , s. 348-351
-
Conference paper (peer-reviewed)
|
|
| 3. |
- Divinyi, Andreas, et al.
(author)
-
Transition Time of GaN HEMT Switches and its Dependence on Device Geometry
- 2023
-
In: 2023 18th European Microwave Integrated Circuits Conference, EuMIC 2023. ; , s. 46-49
-
Conference paper (peer-reviewed)abstract
- This paper presents the impact on the slow transition time of GaN HEMT switch transistor due to size and geometry. Measurements in the time domain are used to characterize the transition time of the switch from off to on. This is done for several switch transistors with variations on total gate width and number of fingers. In order to enable the comparison of transition times a figure of merit is established. This is achieved by using a commonly used model for trapping effects to quantify the amplitude of the slow transient with respect to the gate voltage. The resulting analysis indicates that transition time is sensitive to transistor size and dependent on the geometry of the device as increasing the width of the gate fingers is more advantageous compared to increasing the number of fingers.
|
|
| 4. |
- Nilsson, Joakim, et al.
(author)
-
S-band discrete and MMIC GaN power amplifiers
- 2009
-
In: European Microwave Week 2009, EuMW 2009: Science, Progress and Quality at Radiofrequencies, Conference Proceedings - 39th European Microwave Conference, EuMC 2009. - 9782874870125 ; , s. 495-498
-
Conference paper (peer-reviewed)abstract
- The use of GaN devices for microwave power amplifiers begins to be a reality in Europe. This paper describes two S-band (2.7-3.3 GHz) high power amplifier (HPA) designs; one discrete 100 W output stage and one 10 W MMIC power amplifier. The discrete power amplifier is designed using two GaN power bars with a total gate width of 19.2 mm. The GaN power bars have been developed by Selex-SI, within the european co-project Korrigan. The MMIC power amplifier was designed using a 0.25 ?m GaN HEMT process supplied and processed by Chalmers.
|
|
| 5. |
- Sudow, Mattias, 1980, et al.
(author)
-
An AlGaN/GaN HEMT-Based Microstrip MMIC Process for Advanced Transceiver Design
- 2008
-
In: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:8, s. 1827-1833
-
Journal article (peer-reviewed)abstract
- A MMIC process in AlGaN/GaN technology for advanced transceiver design has been developed. The process is based on microstrip technology with a complete model library of passive elements and AlGaN/GaN HEMTs. The transistor technology in this process is suitable for both power and low noise design, demonstrated with a power density of 5 W/mm, and an ${rm NF}_{min}$ of 1.4 dB at $X$ -band. Process stability of subcircuits, complementary to power amplifiers and LNAs, in a transceiver system have been investigated. The results indicate that an all AlGaN/GaN MMIC transceiver is realizable using this technology.
|
|
| 6. |
- Sudow, Mattias, 1980, et al.
(author)
-
An SiC MESFET-based MMIC process
- 2006
-
In: IEEE Transactions on Microwave Theory and Techniques. ; 54:12, Part 1, s. 4072-4078
-
Journal article (peer-reviewed)abstract
- A monolithic microwave integrated circuit (MMIC)process based on an in-house SiC MESFET technology has been developed. The process uses microstrip technology, and a complete set of passive components, including MIMcapacitors, spiral inductors,thin-film resistors, and via-holes, has been developed. The potential of the process is demonstrated by an 8-W power amplifierat 3 GHz, a high-linearity -band mixer showing a third-order intercept point of 38 dBm, and a high-power limiter.
|
|
| 7. |
- Sudow, Mattias, 1980, et al.
(author)
-
The Chalmers microstrip SiC MMIC Process
- 2005
-
In: Conference Proceedings Gighahertz 2005.
-
Conference paper (peer-reviewed)abstract
- A generic microstrip MMIC process targeted for SiC and GaN technology has beendeveloped. Passive components for high power operation were developed and verified. Circuit modelsfor both passive and active components have been formulated. Using the developed MMIC process anamplifier and a limiter have been manufactured.
|
|
| 8. |
- Thorsell, Mattias, 1982, et al.
(author)
-
An X-Band AlGaN/GaN MMIC Receiver Front-End
- 2010
-
In: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 20:1, s. 55-57
-
Journal article (peer-reviewed)abstract
- This letter presents an integrated AlGaN/GaN X-band receiver front-end. This is to the authors knowledge the first published results of an integrated AlGaN/GaN MMIC receiver front-end. The receiver uses an integrated SPDT switch to reduce size, weight and cost compared to circulator based transceiver front-ends. The integrated front-end has more than 13 dB of gain and a noise figure of 3.5 dB at 11 GHz.
|
|
| 9. |
|
|
| 10. |
- Billström, Niklas, et al.
(author)
-
Can we improve acoustic environments by adding sound
- 2012
-
In: Proceedings of the 41st International Congress and Exposition on Noise Control Engineering. - 9781627485609
-
Conference paper (other academic/artistic)abstract
- Sound is central to the identity of a place, but is nonetheless a frequently neglected component in the design process. We believe that urban soundscape planning and product sound design has much to gain by collaborating with the artistic and humanistic fields of knowledge. Applying acoustics and perception psychology as well, the sound laboratory at Konstfack University College of Arts, Crafts and Design examined the domain of acoustic design in the research project ISHT – The Interior Sound Design of High-Speed Trains – in collaboration with, among others, train manufacturer Bombardier. Empirical data in this study is focused on train travel, but can easily be transposed to other contexts, such as public spaces. Methods for improving sonic experience in relation to criteria such as identity and specific needs were explored. Our thesis question was: How to create a comfortable and appealing environment by adding sounds (distributed via speakers)? The interdisciplinary research methods included field observations, listening tests, and quantitative data, as well as public exhibitions and collaborations with composers.
|
|
| 11. |
- Hanning, Lowisa, 1993, et al.
(author)
-
Optimizing the Signal-To-Noise and Distortion Ratio of a GaN LNA using Dynamic Bias
- 2018
-
In: 2018 91st ARFTG Microwave Measurement Conference: Wideband Modulated Test Signals for Network Analysis of Wireless Infrastructure Building Blocks, ARFTG 2018. - 9781538654491 ; 1
-
Conference paper (peer-reviewed)abstract
- This paper shows how the signal-to-noise and distortion ratio (SNDR) for low noise amplifiers (LNA) can be derived from the commonly specified parameters noise figure, gain, third order output intercept point and 1 dB compression point. The parameters dependency of the biasing of the amplifier are also incorporated which enables the possibility to study how SNDR can be optimized for different operating conditions by dynamically change the gate- and drain voltage. An experimental verification shows that improvements in SNDR can be achieved by selecting gate- and drain voltage of the LNA according to the level of the input signal power.
|
|
| 12. |
- Landberg, Niklas, et al.
(author)
-
Primary cells in BCR/FGFR1-positive 8p11 myeloproliferative syndrome are sensitive to dovitinib, ponatinib, and dasatinib
- 2017
-
In: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 99:5, s. 442-448
-
Journal article (peer-reviewed)abstract
- Objectives: Translocations involving the fibroblast growth factor receptor 1 (FGFR1) gene are associated with the 8p11 myeloproliferative syndrome (EMS), a rare neoplasm that following a usually short chronic phase progresses into acute myeloid or lymphoid leukemia. The treatment commonly involves chemotherapy and, if possible, allogeneic stem cell transplantation which is the only therapeutic option for long-term survival. Given the aggressive course of EMS, we here evaluated tyrosine kinase inhibitors as treatment options to delay disease progression. Methods: We described a new case of EMS and used chromosome analyses, PCR, and sequencing to investigate the underlying genetic aberrations. The sensitivity to several tyrosine kinase inhibitors was tested in vitro on the EMS cell line KG1 and on primary cells from the newly diagnosed EMS patient. Results: A translocation involving chromosomes 8 and 22 was detected, and a BCR/FGFR1 fusion gene was confirmed and characterized by sequencing. KG1 cells and primary EMS cells displayed distinct sensitivity to dovitinib, ponatinib, and dasatinib as compared to normal bone marrow control cells. Conclusions: These results suggest that treatment with tyrosine kinase inhibitors may be beneficial for patients with EMS during the search for a suitable stem cell donor and for those not eligible for transplantation.
|
|
| 13. |
|
|
