| 1. |
- Sudow, Mattias, 1980, et al.
(författare)
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A Single-Ended Resistive $X$-Band AlGaN/GaN HEMT MMIC Mixer
- 2008
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:10, s. 2201-2206
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Tidskriftsartikel (refereegranskat)abstract
- A broadband highly linear X-band mixer in AlGaN/GaN monolithic microwave integrated circuit technology has been designed, processed, and characterized. The design is based on a 4 times 100 mum AlGaN/GaN HEMT in a single-ended circuit topology. The mixer has an IF bandwidth of 2 GHz with a conversion loss (CL) of
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| 2. |
- Sudow, Mattias, 1980, et al.
(författare)
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An AlGaN/GaN HEMT-Based Microstrip MMIC Process for Advanced Transceiver Design
- 2008
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:8, s. 1827-1833
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
- Sudow, Mattias, 1980, et al.
(författare)
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SiC varactors for dynamic load modulation of high power amplifiers
- 2008
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 29:7, s. 728-730
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Tidskriftsartikel (refereegranskat)abstract
- SiC Schottky diode varactors with a high breakdown voltage, a high tuning ratio, and a low series resistance have been designed and fabricated. These characteristics are particularly necessary for the dynamic load modulation of high power amplifiers (PAs), which is an attractive alternative to other efficiency enhancement techniques. For a SiC Schottky diode varactor with a 50-µm radius fabricated by using a graded doping profile, a breakdown voltage of 40 V, a tuning range of 5.6, and a series resistance of 0.9 O were achieved. The results show the great potential of this type of varactors for the use in the dynamic load modulation of high power amplifiers. © 2008 IEEE.
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| 4. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Characterization of the temperature dependent access resistances in AlGaN/GaN HEMTs
- 2008
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Ingår i: Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits, 2008. INMMIC 2008.. - 9781424426454 ; , s. 17-20
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Konferensbidrag (refereegranskat)abstract
- The temperature dependence of the access resistances for AlGaN/GaN HEMTs is investigated. The self-heating is measured using infrared microscopy and the access resistances are extracted at different ambient temperatures. Their influence on the intrinsic small signal parameters is studied versus bias and ambient temperature.
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| 5. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Thermal characterization of the intrinsic noise parameters for AlGaN/GaN HEMTs
- 2008
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Ingår i: International Microwave Symposium Digest, 2008, Atlanta. - 0149-645X. - 9781424417810 ; , s. 463-466
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Konferensbidrag (refereegranskat)abstract
- The noise parameters of AlGaN/GaN-HEMTs are measured between 298 K and 423 K. The temperature dependent access resistances are de-embedded and the intrinsic noise parameters are studied as a function of temperature. It is shown that the parasitic access resistances are limiting the highfrequency noise performance of the AlGaN/GaN-HEMT.The intrinsic noise sources are extracted and a noise model is derived and verified for a MMIC amplifier.
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| 6. |
- Thorsell, Mattias, 1982, et al.
(författare)
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Thermal Study of the High-Frequency Noise in GaN HEMTs
- 2009
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:1, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- The high-frequency noise performance of the GaN HEMT is studied for temperatures between 297–398 K. The access resistances ${ R}_{ S}$ and ${ R}_{ D}$ have a limiting effect on the noise performance, and in this paper, their temperature dependence is studied in detail for a ${hbox{2}}times {hbox{100}} mu{hbox{m}}$ GaN HEMT. ${ R}_{ S}$ and ${ R}_{ D}$ show an increase of 0.71 and 0.86 %/K, respectively. The self-heating effect due to dissipated power is also studied to allow accurate intrinsic small-signal and noise parameter extraction. The thermal resistance is measured by infrared microscopy. Based on these results, a temperature dependent noise model including self-heating and temperature-dependent access resistances is derived and verified with measurements.
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| 7. |
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| 8. |
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| 9. |
- Suijker, Erwin M., et al.
(författare)
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GaN MMIC power amplifiers for S-band and X- band
- 2008
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Ingår i: 38th European Microwave Conference, EuMC 2008; Amsterdam; Netherlands; 27 October 2008 through 31 October 2008. - 9782874870064 ; , s. 297-300
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Konferensbidrag (refereegranskat)abstract
- The development of two GaN MMIC power amplifiers is reported. The amplifiers are processed in the AlGaN/GaN technology of Chalmers University of Technology using 0.25 ?m HEMTs. The S-band amplifier operates at frequencies from 3 to 4 GHz and has a maximum output power of 5.6 W with an associated efficiency of 28 %. The X-band amplifier has a maximum output power of 4.8 W.
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| 10. |
- Andersson, Kristoffer, 1976, et al.
(författare)
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Fabrication and characterization of field-plated buried-gate SiC MESFETs
- 2006
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 27:7, s. 573-575
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide (SiC) MESFETs were fabricated using a standard SiC MESFET structure with the application of the "buried-channel" and field-plate (FP) techniques in the process. FPs combined with a buried-gate are shown to be favorable concerning output power density and power-added efficiency (PAE), due to higher breakdown voltage and decreased output conductance. A very high power density of 7.8 W/mm was measured on-wafer at 3 GHz for a two-finger 400-/spl mu/m gate periphery SiC MESFET. The PAE for this device was 70% at class AB bias. Two-tone measurements at 3 GHz /spl plusmn/ 100 kHz indicate an optimum FP length for high linearity operation.
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| 11. |
- Angelov, Iltcho, 1943, et al.
(författare)
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Large-Signal Modelling and Comparison of AlGaN/GaN HEMTs and SiC MESFETs
- 2006
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Ingår i: IEEE Asia PAcific Microwave Conference, 2006, Yokohama, Japan. - 9784902339116 ; , s. 279-282
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Konferensbidrag (refereegranskat)abstract
- The Large Signal (LS) model for GaN and SiC FET devices was developed and evaluated with DC, S, and LS measurements. Special attention was paid to improve the management of harmonics and provide. a more physical treatment of the dispersion. The model was implemented in a commercial CAD tool and exhibit good overall accuracy.
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| 12. |
- Hjelmgren, Hans, 1960, et al.
(författare)
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Electro-thermal simulations of a microwave 4H-SiC MESFET on high purity semi-insulating substrate
- 2007
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101. ; 51:8, s. 1144-1152
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Tidskriftsartikel (refereegranskat)abstract
- DC and small-signal electro-thermal simulations of a 4H-SiC microwave power MESFET on a high purity semi-insulating substrate are compared to measurements. The focus is on the electron transport, substrate traps, and thermal heating. The doping concentrations are described by measured SIMS profiles, and the material parameters are in accordance with published results. Although the simulated MESFET has a p-buffer and a high purity substrate, the simulations show that the density of shallow traps affects the device characteristics.The very good agreement between simulated and measured DC and small-signal characteristics indicates that the models for electron mobility, substrate traps, and heating are the most important to achieve good agreement with measured data.
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| 13. |
- Malmros, Anna, 1977, et al.
(författare)
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TiN thin film resistors for monolithic microwave integrated circuits
- 2010
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Ingår i: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics. - : American Vacuum Society. - 2166-2746 .- 2166-2754. ; 28:5, s. 912-915
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Tidskriftsartikel (refereegranskat)abstract
- Titanium nitride (TiN) thin film resistors (TFRs) have been fabricated by reactive sputter deposition. The TFRs were characterized in terms of composition, thickness, and resistance. Furthermore, a first assessment of the resistor reliability was made by measurements of the resistivity (rho) versus temperature, electrical stress, long-term stability, and thermal infrared measurements. TiN layers with thicknesses up to 3560 angstrom, corresponding to a sheet resistance (R-s) of 10 Omega/square, were successfully deposited without any signs of stress in the films. The critical dissipated power (P-c) showed a correlation with the resistor footprint-area indicating that Joule-heating was the main cause of failure. This was partly substantiated by the thermal infrared measurements.
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| 14. |
- Nilsson, Per-Åke, 1964, et al.
(författare)
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Influence of Field Plates and Surface Traps on Microwave Silicon Carbide MESFETs
- 2008
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Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 55:8, s. 1875-1879
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Tidskriftsartikel (refereegranskat)abstract
- The influence of field plates and surface traps on silicon carbide MESFETs for microwave operation was investigated. By increasing the length of gate-connected field plates from 50 to 800 nm, it was possible to increase the gate–drain breakdown voltage of the devices from 125 to 170 V. At the same time, the current slump effect of traps in the passivation oxide was reduced. By using a combination of field plates and a passivation oxide with low interface trap density, it was possible to reach an output power density of 8 W/mm at 3 GHz.
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| 15. |
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| 16. |
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| 17. |
- Sudow, Mattias, 1980, et al.
(författare)
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A highly linear double balanced Schottky diode S-band mixer
- 2006
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 16:6, s. 336 - 8
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Tidskriftsartikel (refereegranskat)abstract
- A high-level double balanced SiC Schottky diode mixer in SiC monolithic microwave integrated circuit (MMIC) technology has been designed, processed and characterized. The mixer is a single ended in- and output circuit with coupled transformers as baluns to enable a compact design, resulting in a total area of 2.2×2.2mm2. The mixer has a maximum IIP3 of 38dBm and IIP2 of 58dBm at 3.3GHz, and a typical P1 dB of 23dBm in the S-band. The minimum conversion loss was 12dBm at 2.4GHz. The high power operation of the mixer shows that SiC MMIC can perform well in high microwave radiation environments
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| 18. |
- Sudow, Mattias, 1980, et al.
(författare)
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An SiC MESFET-based MMIC process
- 2006
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. ; 54:12, Part 1, s. 4072-4078
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Tidskriftsartikel (refereegranskat)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.
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| 19. |
- Sudow, Mattias, 1980
(författare)
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Development of SiC MESFET Based MMIC Technology
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A SiC MESFET based MMIC process has been successfully developed. This technology has its main potential in high power microwave circuits. It will offer the benefits of the high integration seen in GaAs MMIC at the same time as it will offer the benefits of the high voltage operation seen in Si LDMOS and Si BJTs.Within the framework of this project, passive circuit elements in the form of MIM capacitors, spiral inductors and thin film resistors, based on the inhouse InP MMIC process have been developed with respect to the high power and high voltage requirements of SiC MMIC. This was complemented witha via-hole process to enable microstrip technology and low inductive ground connections for large periphery devices.The high power potential of SiC MMICs are demonstrated by an 8 W amplifier at 3 GHz, a high linearity S-band mixer with an IIP3 of 38 dBm and two high power limiter circuits.
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| 20. |
- Sudow, Mattias, 1980, et al.
(författare)
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Planar Schottky Microwave Diodes on 4H-SiC
- 2005
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Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 483-485, s. 937-940
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Konferensbidrag (refereegranskat)abstract
- Planar microwave Schottky diodes on 4H-SiC have been designed, processed and measured. Different Schottky metals were tested to study the influence on the microwave performance. A maximum extrinsic cut-off frequency of 30.8 GHz was achieved for a tungsten/SiC-Schottky diode. The diode geometry dependence on both the cut-off frequency and the breakdown voltage was investigated. The breakdown voltage was found to be linearly dependent on the anode-cathode distance
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| 21. |
- Sudow, Mattias, 1980, et al.
(författare)
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Planar SiC Schottky Diodes for MMIC Applications
- 2004
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Ingår i: Conference Proceedings. 34th European Microwave Conference (IEEE Cat. No.04EX963). ; 1, s. 153-156
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Tidskriftsartikel (refereegranskat)abstract
- Planar Schottky diodes intended for SiC MMIC applications have been designed, processed and characterised. To our knowledge, this is the first article published on this type of device. The planar design is beneficial since semi-insulating substrates are used in microwave designs to minimise parasitics. The component geometry was studied and a simple distributed model was formulated. Extrinsic cut-off frequencies up to 30.8 GHz were calculated from LCR-measurements.
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| 22. |
- Sudow, Mattias, 1980, et al.
(författare)
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The Chalmers microstrip SiC MMIC Process
- 2005
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Ingår i: Conference Proceedings Gighahertz 2005.
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Konferensbidrag (refereegranskat)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.
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| 23. |
- Sudow, Mattias, 1980
(författare)
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Wide Bandgap MMIC Technology
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wide bandgap technology for microwave electronics has been an intense area of research during the last decade. With reas of application ranging from base station amplifiers to radar transceivers, this technology has the resources to be the basis for the next generation of high power microwave electronics. The unique properties of these transistors have enabled the fabrication of high power, broadband, high efficiency and linear microwave electronics better thanthat possible in either Si or GaAs technology.This work has focused on MMIC (microwave monolithic integrated circuit) technology through development of a process and design technology, and evaluation of typical components for transceiver applications.The MMIC technology is based on SiC MESFETs and AlGaN/GaN HEMTs, and is designed for high power operation with high voltage MIM capacitors (breakdown voltage >200V), low resistance spiral inductors, TaN thin film resistors, and through substrate via-holes. The SiC MESFETs show power densities of 8W/mm at 3GHz, fT /fmax figures of 8/30GHz and a DC transconductance, gm, of 25mS/mm. The AlGaN/GaN HEMTs show power densities of 5W/mm at 10GHz, NFmin of 1.2dB at 10GHz, fT /fmax figures of 23/52GHz and a gm of 300mS/mm.Transceiver circuitry for 3 and 10GHz operation is demonstrated with power amplifiers delivering more than 5W of output power at 3GHz at power added efficiencies (PAE) up to 32%, and 5W at 10GHz at a PAE just below 10%. A 2-18GHz transmit/receive switch with an insertion loss of less than 2dB up to 10GHz is demonstrated for implementation in TDD (time division duplex) systems. Robust small signal amplifiers able to withstand overdrive levels of 5W are demonstrated, as well as highly linear mixers at 3 and 10GHz. An 11.6GHz mixer with an integrated RF preamplifier illustrates the possibility to realize multifunction MMICs in AlGaN/GaN technology, and the capability to use SiC MMIC for power control is demonstrated through a DC/DC converterdemonstrating an 80% conversion efficiency.
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