| 1. |
- Andersson, Mattias, 1982, et al.
(författare)
-
Dielectric loss determination of fine residual waste electrical and electronic equipment for understanding of heat development during microwave pyrolysis
- 2013
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 0165-2370. ; 103, s. 142-148
-
Tidskriftsartikel (refereegranskat)abstract
- Waste electrical and electronic equipment (WEEE) contains rare and valuable metals which are important to recycle, but it also has high organic content. The conventional methods used today for treatment of WEEE cannot recycle 100%; they generate valuable fine residual fractions. For further processing of these residues, microwave pyrolysis has shown to be promising since it reduces the organic content and liberate enclosed metal pieces. However, to fully control the process, the dielectric properties of the materials need to be known but are difficult to determine due to the complex composition and structure of WEEE. This paper aims to describe a suitable procedure for determination of dielectric loss in six WEEE residual fine fractions and to correlate the results to heating behaviour during microwave pyrolysis. Three fractions are "dusts" (light, medium and heavy dust) and three fractions are called "particulate materials" and contain smaller particles (0-7 mm, 0-20 mm and 7-12 mm). The method chosen was Vector Network Analyzer (VNA) using waveguide WR430 equipped with polymer foam to contain the samples which consisted of 1 dl of WEEE fine fraction. The scattering parameters were measured and dielectric loss in the materials was calculated. The measurements were performed in frequency region 1.3-2.7 GHz to include the industrial frequency 2.45 GHz. Differences between dielectric losses for the materials were determined by ANOVA. It was shown that the scattering parameter measurements were rather stable for the dust materials and the losses could be determined. For the larger sized particulate materials a lot of reflection was observed during the measurements, due to fine metal wires in the material. The losses could be determined after removing these wires. The previously observed higher heating rate and shorter time for mass reduction of dusts could not be explained by differences in dielectric loss. However, since VNA measurements indicate that metal wires in the material disturb the field; presence of wires in the particulate materials might be one cause for slower heating rate and observed temperature drops during pyrolysis.
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| 2. |
- Lai, Szhau, 1985, et al.
(författare)
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Accurate Phase-Noise Prediction for a Balanced Colpitts GaN HEMT MMIC Oscillator
- 2013
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 61:11, s. 3916-3926
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an X-band balanced Colpitts oscillator in GaN HEMT technology and a method to calculate its phase noise accurately. The method employs a low-frequency (LF) noise measurement and the oscillator waveforms from a harmonic-balance simulator. These data are post-calculated by Hajimiri's phase-noise model, in which the LF noise can be activated with a cyclo-stationary effect in the calculation of phase noise. Compared to commercial phase-noise simulation using predefined stationary noise, the calculation gives significantly improved phase-noise prediction in the 30-dB/decade region near carrier. The prediction is within 3-dB accuracy at 10-kHz, 100-kHz, and 1-MHz offset frequencies. In addition to the method used for phase-noise prediction, the potential for wideband tuning of this oscillator topology is analytically investigated. The measured phase noise of the oscillator is -102 dBc/Hz at 100-kHz offset from a 8.6-GHz carrier frequency for drain voltage and current of Vd = 15 V amd Id = 40 mA.
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| 3. |
- Ringlander, Johan, et al.
(författare)
-
Hepatitis B virus particles in serum contain minus strand DNA and degraded pregenomic RNA of variable and inverse lengths
- 2024
-
Ingår i: LIVER INTERNATIONAL. - 1478-3223 .- 1478-3231.
-
Tidskriftsartikel (refereegranskat)abstract
- This study utilized digital PCR to quantify HBV RNA and HBV DNA within three regions of the HBV genome. Analysis of 75 serum samples from patients with chronic infection showed that HBV RNA levels were higher in core than in S and X regions (median 7.20 vs. 6.80 and 6.58 log copies/mL; p < .0001), whereas HBV DNA levels showed an inverse gradient (7.71 vs. 7.73 and 7.77 log copies/mL, p < .001). On average 80% of the nucleic acid was DNA by quantification in core. The core DNA/RNA ratio was associated with viral load and genotype. In individual patients, the relations between RNA levels in core, S and X were stable over time (n = 29; p = .006). The results suggest that pregenomic RNA is completely reverse transcribed to minus DNA in approximate to 75% of the virus particles, whereas the remaining 25% contain both RNA and DNA of lengths that reflect variable progress of the polymerase.
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| 4. |
- ÖZEN, MUSTAFA, 1984, et al.
(författare)
-
High efficiency RF pulse width modulation with tunable load network class-E PA
- 2011
-
Ingår i: 2011 IEEE 12th Annual Wireless and Microwave Technology Conference, WAMICON 2011. - 9781612840819
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a 10 W peak power 2 GHz highly efficient RF pulse width modulation (RF-PWM) based transmitter is presented. RF-PWM signals are generated with a dedicated 65 nm CMOS modulator and subsequently amplified with a GaN Class-E power amplifier (PA). The modulator use extended drain MOS (EDMOS) high voltage transistors to provide the required voltage swing to drive the GaN used as a switch. The imaginary load impedance of the Class-E is electronically tunable and is implemented with in-house high breakdown voltage SiC varactors. The tunable imaginary load impedance enables optimization of the Class-E versus the duty cycle (pulse width). The peak efficiency is therefore preserved over a wide range of output power levels. The measured drain efficiency of the Class-E output stage is above 70% over a 6.5 dB output power dynamic range. The overall transmitter efficiency is above 60% for the same dynamic range.
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| 5. |
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| 6. |
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| 7. |
- Andersson, Kristoffer, 1976, et al.
(författare)
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Fabrication and characterization of field-plated buried-gate SiC MESFETs
- 2006
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 27:7, s. 573-575
-
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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| 8. |
- Andersson, Kristoffer, 1976, et al.
(författare)
-
Large-signal waveform acquisition of pulsed signals
- 2011
-
Ingår i: European Microwave Week 2011: "Wave to the Future", EuMW 2011, Conference Proceedings - 41st European Microwave Conference, EuMC 2011. - 9782874870224 ; , s. 9010-913
-
Konferensbidrag (refereegranskat)abstract
- Techniques for measuring large-signal waveforms of pulsed signals are fairly well described in the literature. However, most techniques are developed for very specific setups and typically require modification of the hardware. In this paper we describe an approach were no modification is necessary to the existing (Large-Signal Network Analyzer) LSNA hardware and software. Furthermore our method is very well suited for integration with other pulsed stimuli e.g. pulsed IV.
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| 9. |
- Andersson, Kristoffer, 1976
(författare)
-
Microwave power device characterization
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The first part of the thesis covers work done on device characterizationmethods. A statistical method for estimating small-signal model parametersin FET-models was proposed. A maximum likelihood estimator wasderived and the new method was compared to a standard direct extractiontechnique. The comparison showed that the proposed method gaveparameter estimates that were less uncertain than the direct method.A method for extracting the thermal impedance of microwave transistorswas developed. The method was derived from a thorough theoreticalanalysis of the self-heating feedback problem. The method usessmall-signal measurements at low-frequency and a temperature controlledfixture.A technique for improving dynamic range in oscilloscope based RFmeasurements was also presented. The technique uses repeated measurementssynchronized at baseband and an extended Kalman filter for estimatingthe unknown RF-phase, which allowed for averaging and thusreduction of measurement noise. The technique was then used in anerror-corrected source-pull setup. The error-correction takes in to accountgroup-delay variations over the measurement bandwidth.The second part of the thesis contains experimental results on mixercircuits fabricated using wide bandgap semiconductor devices. Hybrid resistiveFET mixers were fabricated for S- and C-band operation. BothSiC-MESFETs and AlGaN/GaN-HEMTs were evaluated as mixing elements.The best performance was achieved with an AlGaN/GaN-HEMT,with a minimum conversion loss of 7 dB and a maximum third-order interceptpoint of 36 dBm. A monolithic integrated double balanced Schottkydiode ring mixer was also designed. The mixer was fabricated in Chalmersin-house SiC-MMIC process. The mixer had a minimum conversion lossof 12 dB and a maximum third order intercept of 38 dBm.
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| 10. |
- Andersson, Kristoffer, 1976, et al.
(författare)
-
Oscilloscope based two-port measurement system using error-corrected modulated signals
- 2012
-
Ingår i: 2012 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits, INMMIC 2012. - 9781467329491
-
Konferensbidrag (refereegranskat)abstract
- A technique to accurately measure modulated wideband signals in a two-port context is presented. The technique uses a four channel high frequency digital sampling oscilloscope to perform in-situ correction of both amplitude and phase of the modulated stimulus signal. An advantage of the proposed technique is that no assumption about the group delay has to be made. The technique is demonstrated in a source-pull system. The results clearly demonstrate the necessity of using error-correction in tuner based setups due to the large variations in group-delay over the measurement bandwidth. © 2012 IEEE.
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| 11. |
- Andersson, Kristoffer, 1976, et al.
(författare)
-
Resistive SiC-MESFET mixer
- 2002
-
Ingår i: IEEE Microwave and Wireless Components Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1531-1309 .- 1558-1764. ; 12:4, s. 119-121
-
Tidskriftsartikel (refereegranskat)abstract
- A single-ended silicon carbide resisitve MESFET mixer with minimum conversion loss (CL) of 10.2 dB and an input third order intercept point of 35.7 dB at 3.3 GHz was designed and characterized. A lumped-element, large-signal model was used for modeling the device. The drain-source resistance was measured by taking the real part of the output port impedence. Analysis suggested that the optimum gate bias for minimum CL was -6.7 V.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Angelov, Iltcho, 1943, et al.
(författare)
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Large-Signal Modelling and Comparison of AlGaN/GaN HEMTs and SiC MESFETs
- 2006
-
Ingår i: IEEE Asia PAcific Microwave Conference, 2006, Yokohama, Japan. - 9784902339116 ; , s. 279-282
-
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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| 18. |
- Angelov, Iltcho, 1943, et al.
(författare)
-
On the Compact Equivalent Circuit Modeling
- 2010
-
Ingår i: APMC 2010 invited workshop. ; APMC 2010 invited workshop:APMC 2010 invited workshop
-
Konferensbidrag (refereegranskat)
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| 19. |
- Angelov, Iltcho, 1943, et al.
(författare)
-
On the Large Signal Evaluation and Modeling of GaN FET
- 2010
-
Ingår i: IEICE Transactions on Electronics. - 0916-8524. ; E93C:8, s. 1225-1233
-
Tidskriftsartikel (refereegranskat)abstract
- The large signal performance and model for GaN FET devices was evaluated with DC, S-parameters, and large signal measurements. The large signal model was extended with bias and temperature dependence of access resistances, modified capacitance and charge equations, as well as breakdown models. The model was implemented in a commercial CAD tool and exhibits good overall accuracy.
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| 20. |
- Angelov, Iltcho, 1943, et al.
(författare)
-
On the large-signal modeling of High Power AlGaN/GaN HEMTs
- 2012
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
-
Konferensbidrag (refereegranskat)abstract
- In this paper are given some recent results on modeling of High Power GaN HEMT devices. The GaN HEMT is very promising for high power application, but we push device to the limits, so many issues are becoming critical. For example, access resistances Rs, Rd in high power GAN HEMT are bias and temperature dependent-their extraction from cold FET measurements can lead to over optimistic prediction for output power. Thermal management, self-heating modeling are another very important issue-they influence reliability, power and PAE. Models without dynamic self-heating are not practical for GaN. The models without breakdown can easily predict world records for PAE, output power/mm etc. Some examples are given using vectorial Large Signal Measurements (LSNA/NVNA) to provide useful, global info about device behavior, influence of traps, knee voltage walkout etc.
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| 21. |
- Axelsson, Olle, 1986, et al.
(författare)
-
Highly linear gallium nitride MMIC LNAs
- 2012
-
Ingår i: 2012 IEEE Compound Semiconductor Integrated Circuit Symposium, CSICS 2012, La Jolla, CA, 14 - 17 October 2012. - 1550-8781. - 9781467309295
-
Konferensbidrag (refereegranskat)abstract
- In this paper, two Low Noise Amplifiers designed in Gallium Nitride HEMT MMIC technology are presented. The focus of the designs is to achieve good linearity at low power consumption and acceptable noise figure. The first design achieves an OIP3/PDC of 12 using traditional LNA design techniques. In a second design, the OIP3 is improved by 2 dB, raising OIP3/PDC to 19, among the highest figures reported for GaN LNAs. This is achieved by using both inductive source feedback and drain-gate RC feedback.
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| 22. |
- Axelsson, Olle, 1986, et al.
(författare)
-
Noise temperature of an electronic tuner for noise parameter measurement systems
- 2012
-
Ingår i: 79th ARFTG Microwave Measurement Conference: Non-Linear Measurement Systems, ARFTG 2012. ; , s. Article number 6291197-
-
Konferensbidrag (refereegranskat)abstract
- In this paper, the noise temperature of an electronic tuner is determined and its significance for the suitability of such tuners in noise parameter measurement systems discussed. The noise temperature of the tuner was found to be higher than the ambient room temperature in the laboratory and vary significantly between tuner states. For impedance states with small input reflections coefficients, the excess noise temperature is around 25 K. For some of the states with higher reflection coefficients, this figure increases, reaching around 45 K at |Γ| = 0.75. Unless accounted for, this leads to errors in noise parameter extraction when using an electronic tuner in noise parameter measurements.
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| 23. |
- Bremer, Johan, 1991, et al.
(författare)
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Electric-Based Thermal Characterization of GaN Technologies Affected by Trapping Effects
- 2020
-
Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 67:5, s. 1952-1958
-
Tidskriftsartikel (refereegranskat)abstract
- This article presents an electric-based methodology for thermal characterization of semiconductor technologies. It is shown that for technologies such as gallium nitride (GaN) high electron mobility transistors, which exhibit several field induced electron trapping effects, the thermal characterization has to be performed under specific conditions. The electric field is limited to low levels to avoid activation of trap states. At the same time, the dissipated power needs to be high enough to change the operating temperature of the device. The method is demonstrated on a test structure implemented as a GaN resistor with large contact separation. It is used to evaluate the thermal properties of samples with different silicon carbide suppliers and buffer thickness.
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| 24. |
- Chehrenegar, Pirooz, 1964, et al.
(författare)
-
Design and characterization of a highly linear 3 GHz GaN HEMT amplifier
- 2011
-
Ingår i: 2011 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits, INMMiC 2011. Vienna, 18-19 April 2011. - 9781457706493
-
Konferensbidrag (refereegranskat)abstract
- In this paper a highly linear amplifier using an in-house gallium nitride (GaN) high electron mobility transistor (HEMT) technology is presented. A 3 dB bandwidth of 2.7-3.6 GHz with a maximum gain of 18 dB was measured. The output third-order intercept point (OIP3) was measured to 39 dBm with a maximum power consumption of 2.1 W. With a reduction of power consumption to 1 W the noise figure was improved by 0.6 dB while the OIP3 was degraded 3 dB.
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| 25. |
- Chehrenegar, Pirooz, 1964, et al.
(författare)
-
Highly linear 1-3 GHz GaN HEMT low-noise amplifier
- 2012
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
-
Konferensbidrag (refereegranskat)abstract
- A highly linear low-noise amplifier (LNA) based on a commercial Gallium Nitride (GaN) high electron mobility transistor (HEMT) technology is presented. The amplifier can be operated at three frequency bands of 1, 2 and 3 GHz. The maximum measured gain is 31 dB at 1GHz and the output referred third-order intercept point (OIP3) is constant for all three frequency bands and equal to 41±1 dBm at a power consumption of L.2 W. A minimum noise figure (NF) of 0.5 dB is measured for the amplifier at the same bias point demonstrating the simultaneous linearity and low noise performance. The presented performance together with the reasonably low power consumption is outstanding in comparison with recently published amplifiers in GaN technology and available commercial GaAs LNAs.
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| 26. |
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| 27. |
- Fager, Christian, 1974, et al.
(författare)
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Improvement of Oscilloscope Based RF Measurements by Statistical Averaging Techniques
- 2006
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; , s. 1460-1463
-
Konferensbidrag (refereegranskat)abstract
- This paper demonstrates a method for accurate characterization of modulated microwave signals using a digital storage oscilloscope (DSO). Repeated measurements of the modulated signal are used with statistical averaging techniques to significantly improve the dynamic range. The performance of the method is evaluated by residual EVM and RF spectrum measurements. AM/AM measurements using two DSO channels are used to demonstrate the ability to perform synchronous input/output PA characterization.
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| 28. |
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| 29. |
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| 30. |
- Ferndahl, Mattias, 1973, et al.
(författare)
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A General Statistical Equivalent-Circuit-Based De-Embedding Procedure for High-Frequency Measurements
- 2008
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:12, s. 2692-2700
-
Tidskriftsartikel (refereegranskat)abstract
- A general equivalent-circuit-based method for the de-embedding of scattering parameters is presented. An equivalent circuit representation is used to model the embedding package. The parameters in the models are estimated with a statistical method using measured data from all de-embedding standards jointly together. Hence, it is possible to assess parameter estimates and their variance and covariance due to measurement uncertainties. A general de-embedding equation, which is valid for any five-port with a defined nodal admittance matrix, is derived and used in the subsequent de-embedding of measured device data. Different equivalent circuit models for the embedding network are then studied, and tradeoffs between model complexity and uncertainty are evaluated. Furthermore, the influence of varying number and combinations of de-embedding standards on the parameter estimates is investigated. The method is verified, using both measured and synthetic data, and compared against previously published work. It is found to be more general while keeping or improving accuracy.
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| 31. |
- Ferndahl, Mattias, 1973, et al.
(författare)
-
Multi-line TRL calibration compared to a general de-embedding method
- 2009
-
Ingår i: ARFTG 73rd Microwave Measurement Conference. ; 1
-
Konferensbidrag (refereegranskat)abstract
- A direct comparison between a newly proposedgeneral equivalent-circuit-based de-embedding method and amulti-line TRL calibration is presented.It is shown that the de-embedding method yields corrected/intrinsic S-parameters with good accuracy when comparedto the calibration, even up to 100 GHz hence, validating the deembeddingmethod. Furthermore, in the de-embedding, differentequivalent-circuit models with varying complexity for the embeddingnetwork are compared and evaluated.
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| 32. |
- Gudjonsson, Gudjon, 1973, et al.
(författare)
-
Design and Fabrication of 4H-SiC RF MOSFETs
- 2007
-
Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 54:12, s. 3138-3145
-
Tidskriftsartikel (refereegranskat)abstract
- We present simulations, fabrication and analysis of 4H-SiC RF power MOSFETs. We obtain an extrinsic transition frequency of 11.2 GHz and an f max = 11.9 GHz, a breakdown voltage above 200 V and an output power of 1.9 W/mm at 3 GHz. The measured devices are double fingered, source-gate-draingate-source with 2 × 0.4 mm total gate width and the nominal channel length of the devices is 0.5 μm. To the authors knowledge, this is the highest transition frequency and output power density ever reported for SiC RF MOSFETs. The antipunchthrough is introduced as a way to take advantage of the SiC's material properties. A detailed description of the device processing is also given. © 2007 IEEE.
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| 33. |
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| 34. |
- Gudjonsson, Gudjon, 1973, et al.
(författare)
-
High Power Density 4H-SiC RF MOSFETs
- 2006
-
Ingår i: IEEE Electron Device Letters. ; 527-529, s. 1277-1280
-
Tidskriftsartikel (refereegranskat)
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| 35. |
- Hjelmgren, Hans, 1960, et al.
(författare)
-
Electro-thermal simulations of a microwave 4H-SiC MESFET on high purity semi-insulating substrate
- 2007
-
Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101. ; 51:8, s. 1144-1152
-
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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| 36. |
- Hjelmgren, Hans, 1960, et al.
(författare)
-
Extraction of an Electrothermal Mobility Model for AlGaN/GaN Heterostructures
- 2012
-
Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 59:12, s. 3344-3349
-
Tidskriftsartikel (refereegranskat)abstract
- An electron mobility model for AlGaN/GaN heterostructures taking both the lattice temperature and electric field into account is proposed. Numerical device simulation of an ungated Al0.25Ga0.75N/GaN HEMT structure on 4H-SiC substrate is compared to measured electrical characteristics. Mobility model parameters are extracted by comparing iso-thermal numerical simulations with microwave (6 GHz) large signal measurements. The extracted model was used in static simulations, showing good agreement with measurements.
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| 37. |
- Hjelmgren, Hans, 1960, et al.
(författare)
-
Transient Simulation of Microwave SiC MESFETs With Improved Trap Models
- 2010
-
Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 57:3, s. 729-732
-
Tidskriftsartikel (refereegranskat)abstract
- Measured and simulated transient characteristics ofa SiC metal–semiconductor field-effect transistor are compared. Self-heating, gate tunneling, substrate, and surface traps are taken into account in the simulations. By explicitly filling surface traps at the vicinity of the gate during pinchoff, close correspondence between simulated and measured gate lags is achieved.
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| 38. |
- Landin, Per N., et al.
(författare)
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Power Amplifier Behavioral Modeling Performance Comparison of the LSNA and the Modulation-Domain System
- 2008
-
Ingår i: 72ND ARFTG MICROWAVE MEASUREMENT SYMPOSIUM - TIME DOMAIN AND FREQUENCY DOMAIN MEASUREMENT. - New York : IEEE. - 9781424422999 ; , s. 73-78, s. 73-78
-
Konferensbidrag (refereegranskat)abstract
- The performance of power amplifier behavioral models depends strongly on the performance of the system used to measure the amplifiers. In this study two different systems with nonlinear measurement capability are used to model a commercially available PA. One system is a large-signal network analyzer (LSNA) and the second system is a modulation-domain system (MDS) consisting of a vector signal generator and a vector signal analyzer. The PA was tested with multitone and WCDMA signals and behavioral models were extracted from the measured data. The evaluation criteria normalized mean square error and weighted error spectral power ratio or adjacent channel error power ratio were then computed to compare the performance of the models from the two systems. Cross-validation between the systems, using data from one system to obtain the model and validating its performance with data from the other system, shows that the model performance is mainly affected by the used validation data. Validating the performance of models from the LSNA with data from the MDS indicates that the identified models have almost the same performance as the MDS-identified models, i.e. it does not matter which system is used to identify the models. Cross-validation using a WCDMA-signal and multitone signal from the different systems shows that the normalized mean square error is mainly affected by modeling imperfections introduced by using another signal type. WESPR and ACEPR show a certain difference in performance with somewhat lower values for the MDS. The behavior of the two systems can be explained by different noise levels.
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| 39. |
- Malmqvist, Robert, et al.
(författare)
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A W-Band Single-Chip Receiver in a 60 nm GaN-on-Silicon Foundry Process
- 2021
-
Ingår i: EuMIC 2021 - 2021 16th European Microwave Integrated Circuits Conference. ; , s. 51-54
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a compact W-band heterodyne receiver MMIC realised in a 60 nm GaN-on-Si foundry process. The single-chip receiver consists of an LNA with a measured NF of 4.4-5.5 dB at 90-95 GHz and a resistive down-conversion mixer with a frequency doubler for the multiplication of the LO signal. The measured receiver conversion gain is 0-7.4 dB/0-6.4 dB at 75-91 GHz when the LO/2 power is 20.5 dBm (IF=5 GHz/2 GHz). The measured receiver 1 dB compression point is found to occur at an input power level of -12 dBm and -9 dBm at 80 GHz and 91 GHz, respectively (IF=2GHz). To the best of our knowledge, this single-chip receiver achieves the smallest size (4 mm2), widest RF and IF bandwidths and highest linearity among reported GaN single-chip receivers in this frequency range. The receiver noise figure can be reduced by using an alternative GaN-on-Si LNA design with a measured average NF of 3.6-4.0 dB at 75-95 GHz and a measured maximum input 1 dB compression point of -3 dBm at 95 GHz.
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| 40. |
- Malmqvist, Robert, et al.
(författare)
-
E/W-Band CPW-based Amplifier MMICs Fabricated in a 60 nm GaN-on-Silicon Foundry Process
- 2021
-
Ingår i: EuMIC 2020 - 2020 15th European Microwave Integrated Circuits Conference. ; , s. 137-140
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an experimental evaluation of two co-planar waveguide (CPW) based E/W-band amplifier MMICs realised in a 60 nm GaN-on-Si foundry process. A one-stage amplifier and a two-stage amplifier realised in this process have a measured maximum gain of 8 dB and 16 dB at 73-74 GHz, respectively. The two amplifiers have a measured gain of 3 dB and 7 dB at 93 GHz when the drain voltage (Vd) is 10 V and the drain current (Id) is 15 mA per stage. The two-stage amplifier has a measured noise figure (NF) of 2.7-3.8 dB and 2.9-4.1 dB at 90-95 GHz when the Id is 10 mA and Vd is 5 V and 10 V, respectively. The measured NF of this amplifier is equal to 4-6 dB at 92-95 GHz when an Id of 10-20 mA is used in each stage with same drain bias.
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| 41. |
- Malmros, Anna, 1977, et al.
(författare)
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Combined TiN- and TaN temperature compensated thin film resistors
- 2012
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 520:6, s. 2162-2165
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Tidskriftsartikel (refereegranskat)abstract
- The opposite signs of the temperature coefficient of resistance (TCR) of two thin film materials, titanium nitride (TiN) and tantalum nitride (TaN), were used to form temperature compensated thin film resistors (TFRs). The principle of designing temperature compensated TFRs by connecting TFRs of each compound in series or in parallel was demonstrated. TiN, TaN, and combined TiN and TaN TFRs for monolithic microwave integrated circuits (MMICs) were fabricated by reactive sputtering. DC characterization was performed over the temperature range of 30-200 degrees C. The TiN TFRs exhibited an increase in resistivity with temperature with TCRs of 540 and 750 ppm/degrees C. The TaN TFR on the other hand exhibited a negative TCR of -470 ppm/degrees C. The shunted TFRs were fabricated by serial deposition of TiN and TaN to form a bilayer component. The TCRs of the series- and shunt configurations were experimentally reduced to -60 and 100 ppm/degrees C, respectively. The concept of temperature compensation was used to build a Wheatstone bridge with an application in on-chip temperature sensing.
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| 42. |
- 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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| 43. |
- Mashad Nemati, Hossein, 1980, et al.
(författare)
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High-Efficiency Power Amplifier
- 2011
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Ingår i: IEEE Microwave Magazine. - 1527-3342 .- 1557-9581. ; 12:1, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- P As are usually the most powerconsuming circuit blocks in wireless communication systems. The overall power efficiency of the system is therefore highly dependent on the PA efficiency. The maximum achievable PA efficiency is determined by the RF power transistor technology as well as the external circuitry, which makes the transistor operate in a certain class of operation. Various high-efficiency classes, including switched-mode and harmonically tuned classes, have been proposed in the literature to achieve theoretical efficiencies of up to 100%. © 2011 IEEE.
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| 44. |
- 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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| 45. |
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| 46. |
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| 47. |
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| 48. |
- Otsuka, Hiroshi, et al.
(författare)
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Semi-physical nonlinear circuit model with device/physical parameters for HEMTs
- 2011
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Ingår i: International Journal of Microwave and Wireless Technologies. - 1759-0787 .- 1759-0795. ; 3:1, s. 25-33
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Tidskriftsartikel (refereegranskat)abstract
- A nonlinear circuit model (NCM) with physical parameters is proposed for direct simulation of the RF characteristics of GaN high-electron-mobility transistors (GaN HEMTs) on the basis of device structure. The physical equations are used for the construction of the model in order to connect strongly the model parameters with the device/physical parameters. Hyperbolic tangent functions are used as the model equations to ensure good model convergence and rapid simulation (short simulation time). The usefulness of these equations is confirmed by technology computer aided design (TCAD) simulation. The number of model parameters for the nonlinear components (Ids, Cgs, Cgd) is reduced to 17 by using common physical parameters for modeling the drain current and capacitance. The accuracy of this model is verified by applying to GaN HEMTs. The modeled I–V and capacitance characteristics agree well with the measurement data over a wide voltage range. Furthermore, this model can be used for the accurate evaluation of S-parameters and large-signal RF characteristics.
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| 49. |
- Piazzon, L., et al.
(författare)
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Branch-Line Coupler Design Operating in Four Arbitrary Frequencies
- 2012
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 22:2, s. 67-69
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents a successful design approach for a branch-line coupler operating in four arbitrary frequencies. An optimized compensation technique is adopted to fulfill satisfactory matching, transmission and isolation properties within each operating band. Based on the simple planar microstrip technology, the proposed quad-band coupler has been realized and tested. A return loss better than 16 dB, together with an amplitude imbalance limited to 0.3 dB and an isolation higher than 17.5 dB, have been experimentally measured on each operating band, validating the proposed design methodology.
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| 50. |
- Piazzon, L., et al.
(författare)
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Design Method for Quasi-Optimal Multiband Branch-Line Couplers
- 2014
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Ingår i: International Journal of RF and Microwave Computer-Aided Engineering. - : Hindawi Limited. - 1096-4290 .- 1099-047X. ; 24:1, s. 117-129
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the design approach, the implementation, and experimental results of multiband branch-line couplers operating at arbitrary frequencies are presented. The conventional branch-line coupler structure is adapted to multiband operation by shunting its four ports with multiband reactive networks. The performance of the proposed multiband couplers is theoretically analyzed and optimized through the even-odd mode circuit analysis. Dual-band (2.4-3.5 GHz), triple-band (1.5-2.4-4.2 GHz), and quad-band (1.5-2.4-3.5 GHz) microstrip branch-line couplers have been realized and tested to verify the design method. The good experimental results (input return loss greater than 15 dB and amplitude imbalance lower than 0.7 dB) show excellent agreement with theoretical and simulated ones, thus validating the proposed approach.
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