hig.sePublications
Change search
Refine search result
12345 1 - 50 of 208
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Abbasi, Mahdi
    University of Gävle, Department of Technology and Built Environment.
    Characterization of a 5GHz Modular Radio Frontend for WLAN Based on IEEE 802.11p2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The number of vehicles has increased significantly in recent years, which causeshigh density in traffic and further problems like accidents and road congestions.A solution regarding to this problem is vehicle-to-vehicle communication, wherevehicles are able to communicate with their neighboring vehicles even in the absenceof a central base station, to provide safer and more efficient roads and toincrease passenger safety.The goal of this thesis is to investigate basic physical layer parameters of ainter-vehicle communication system, like emission power, spectral emission, errorvector magnitude, guard interval, ramp-up/down time, and third order interceptpoint. I also studied the intelligent transportation system’s channel layout inEurope, how the interference of other systems are working in co-channel and adjacentchannels, and some proposals to use the allocated frequency bands. On theother hand, the fundamentals of OFDM transmission and definitions of OFDMkey parameters in IEEE 802.11p are investigated.The focus of this work is on the measurement of transmitter frontend parametersof a new testbed designed and fabricated in order to be used at inter-vehiclecommunication based on IEEE 802.11p.

  • 2.
    Abrego peris, Iñaki
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Antenna with medical applications for tumour cancer: hyperthermia function2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The idea is to improve or help the treatments that exist in the market in the medical field. Treatments such as mammography or radiotherapy make use of X-rays. X-rays are electromagnetic radiation in a high frequency band, this type of electromagnetic is dangerous to health because ionizing radiation is used, ionized atoms interact with matter. For this reason, in our work we give alternative solution to these treatments without any risk to health. This project consists in the use of non-harmful frequencies such as microwave. In this way, we will make an antenna with medical applications whose frequency range will be between 300 MHz and 30 GHz, specifically between 950MHz and 2.45GHz (medical range). The first step will be the detection of the tumour and classification of this, but our work is about another technique called hyperthermia. This technique consists in increase the temperature with a value of 40-43 degrees in the tumour area. Tumour resistance decreases when heat is applied to this. When combining a treatment with oncologic hyperthermia, the effect of radiotherapy is most effective (between 1.5-5 times). The most important part is study antenna in body tissues characteristics as SAR, depth penetration and antenna size; this theory part is essential to know the best parameters and what case use this. In work development we will choose and design antennas for the different parts of the body in some specific frequencies and choose circular antennas in frequencies of 915 MHz and 1.8 GHz. Finally, we will take measurements about temperature increase with meat and say some conclusions.

  • 3.
    Adis, Kurtalic
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Linkfire2011Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Planen var att konstruera en PCI-Express-till-PCI brygga för fyra MoCA radiokort. Problem uppstod då det visade sig att PLC8112 inte kunde hantera fyra PCI samtidigt som var utlovat från tillverkaren av bryggan. För att lösa problemet fick PCI6152 läggas till i designen. Det är en PCI-till-PCI brygga som också ska klara att hantera upp till fyra PCI enligt tillverkaren. Fyra MoCA radiokort förbrukar mycket ström. Två spänningsregulatorer lades till i designen för att kunna leverera de strömmar som krävs. För att säkerställa att radiokorten som ansluts till Linkfire inte blir för varma så placeras en temperatursensor under ett radiokort. Temperatursensorn har endast av/på lägen och till den ansluts två fläktar, därmed så betraktas dem som en fläkt då de inte är individuellt styrda.

  • 4.
    Afzal, Nauman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10nal@student.hig.se.
    Udata, Ramakrishna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10rua@student.hig.se.
    Designing and measurement of routing module for transceiver system at 3.125GHz2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This report intends to impart a good understanding of routing modules used in modern transceiver systems. The radar system at RadarBolaget AB needed to have a good routing module for its newly designed transceiver antenna. In this report, studies have been done related to two majorly used routing modules in modern electronics industry; Microwave Circulator and RF/Microwave Switch. First off, different characteristics of routing modules are discussed. After having discussed important design parameters, practical design considerations for two routing modules are presented in a profound way. Theoretical knowledge for both of these two devices is presented in the beginning, followed by their practical designs using standard simulation software like HFSS and ADS. The report concludes its findings in a way that at the end of this report, reader becomes acquainted with ample information to be able to choose the best option available among all of the discussed designs. An FET RF Switch is chosen at the end of this project to be used for transceiver system which should be able to satisfy specifications specified by RadarBolaget AB. This project was carried out by two students of Master Program in Electronics/Telecommunications at Högskolan i Gävle in collaboration with RadarBolaget AB, Gävle, Sweden.    

  • 5.
    Ahmed Mohamed Ahmed, Mazz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Traffic Model Based Energy Efficient Radio Access Network2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As the concerns about global energy consumption increased the matter of energy consumption in Radio Access Networks (RANs) became an important issue especially with the exponential growth in demanded traffic. This interest of developing innovative technologies to reduce the expected energy consumption by the mobile communication sector was driven by environmental concerns and cost reduction.

    The aim of this thesis is to introduce a new methodology to make the Radio Access Network (RAN) more energy efficient based on jointly the demanded throughput and a realistic traffic profile. Furthermore, to find a metric that quantifies the relation between the Energy Efficiency (EE), Spectrum Efficiency (SE) and demanded throughput.

    The proposed methodology for reducing the energy consumption in the RAN characterizes the offered throughput in order to determine the sufficient energy needed. The manner for reducing the energy consumed by the RAN is simply by switching (OFF/ON) Base Stations (BSs) based on the demanded throughput which introduces an energy efficient RAN.

    The results show a significant reduction in the energy consumption with regard to the demanded traffic. Moreover, it gives a measure of the EE with consideration to the SE which enhances the performance evaluation from an EE point of view during the RAN planning phase.

  • 6.
    Al Tanany, Ahmed
    University of Gävle, Department of Technology and Built Environment.
    A Study of Switched Mode Power Amplifiers using LDMOS2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    This work focuses on different kinds of Switch Mode Power Amplifiers (SMPAs) using LDMOS technologies. It involves a literature study of different SMPA concepts. Choosing the suitable class that achieves the high efficiency was the base stone of this

    work. A push-pull class J power amplifier (PA) was designed with an integrated LC resonator inside the package using the bondwires and die capacitances. Analysis and motivation of the chosen class is included. Designing the suitable Input/Output printed circuit board (PCB) external circuits (i.e.; BALUN circuit, Matching network and DC

    bias network) was part of the work. This work is done by ADS simulation and showed a simulated result of about 70% drain efficiency for 34 W output power and 16 dB gain at 2.14 GHz. Study of the losses in each part of the design elements is also included.

    Another design at lower frequency (i.e.; at 0.94 GHz) was also simulated and compared to the previous design. The drain efficiency was 83% for 32 W output power and 15.4 dB Gain.

  • 7.
    Almgren, Björn
    University of Gävle, Department of Technology and Built Environment.
    Dynamic load modulation2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The purpose of this master thesis was to study if the drain efficiency of power amplifiers can be maintained at power back off using a technique called load modulation.

    The amplifier classes studied are E, F and D-1. The target figure was to obtain a 10 to 12 dB dynamic range of amplitude with reasonable efficiency. Studies of power amplifiers have been made to understand how power is generated. Several different load modulation networks have been evaluated. Attempts to derive design equations for the modulation networks have also been done.

    The thesis work was carried out with simulations in ADS 2006. As active devices commercially available bare-die transistor models have been used. The power rating of the dies are 15 W.

    A dynamic range of amplitude of over 15 dB has been achieved with drain efficiency greater than 60 percent. The peak output power is in the 40 – 45 dBm range.

  • 8.
    Almingol, Oscar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Construction of a C-PV prototype2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The following Master Thesis will talk about a C-PV prototype using bifacial PV technology, based on the Solarus Collector. The Solarus Collector consists in two PV cells built on a metallic receiver, where there are some water channels flowing through it, allowing to cool down the PV cells, thus increasing their efficiency. The collector also presents a reflector to provide irradiance to the back part of the receiver, where the other PV cells are located. The new prototype will present bifacial PV cells but not a metallic receiver. This construction aims to reduce the price of the receiver, but will not have a system to cool down the solar cells. This Master Thesis will be developed in the Solarus facilities, in collaboration with the Solarus members.

    In order to grasp an idea of this prototype, two main procedures will be done. Regarding the bifacial technology, a bifacial PV module will be measured under different conditions, depending on which sides can be illuminated or shaded. On the other hand, a thermodynamic simulation will be carried out on different geometries of the reflector and receiver, in order to figure out the evolution of the temperatures on the new prototype. This simulation will be done with a finite element method, widely known in this applications.

    The results will show several problems concerning this prototype. Although the measurements of the bifacial PV module will result beneficial and informative, the problem with the temperature will tend to back down this prototype. The lack of some system to cool down the bifacial cells will imply that the receiver could reach unacceptable temperatures. This hypothesis will be drawn under some specific conditions, so they will not be completely devastating to the idea of using bifacial cells, but perhaps a different approach should be used in case it is desired to continue this work. 

  • 9.
    AMIN, AHMED
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Implementation and Investigation of VDSL2 Signal Modulation/Demodulation Functions for FDM Solution via POF Channel2011Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    For higher data rate and attractive price level internet service Very High Data rate Subscriber Line 2 (VDSL2) is a perfect option. VDSL2 is a great achievement in Digital Subscriber Line (DSL) technology. It has a good impact in modern triple play (Voice, Data and Video) Internet service but for modern world applications required more data rate than the VDSL2 system can provide but it should be inexpensive and easy to install. So the desired goal of this thesis work is to achieve higher bitrates for VDSL2 system, by transmitting multiple VDSL2 signal using Plastic Optical Fiber (POF) channel instead of copper channel. POF channel is a suitable solution for high data rate application. Moreover POF is very rugged and suitable for high data rate application because of optical based transmission and it’s also very easy to implement into the interior networking. Moreover POF doesn’t have any impact of Electro Magnetic Interference because of optical transmission. So several VDSL2 signals are amplitude modulated to allocate specific frequency band and combined together which can be called as frequency division multiplexing and POF is used as channel to carry the combined signal which provide much higher bit rate than single signal and efficiently utilize the bandwidth of the channel. Then at the receiver end the combined signals are split and amplitude demodulate at the respective receiver to recover the expected frequency band for the receiver.       

  • 10.
    Andersen, Olav
    et al.
    Ericsson.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Keskitalo, Niclas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Test-Bed Designed to Utilize Zhu’s General Sampling Theorem to Characterize Power Amplifiers2009In: Instrumentation and measurement technology conference 2009 I2MTC '09 IEEE, Singapore, 2009, 201-204 p.Conference paper (Refereed)
    Abstract [en]

    Characterizing power amplifiers require test set-ups with performance superior to the power amplifiers. A commonly used method is to use an IQ-demodulator. However, problem arises due to imperfections in the demodulator such as IQ-imbalance; an alternative method is to use a direct down converter to intermediate frequency. The drawback then is the limited bandwidth. However, the required bandwidth of the ADC does not need to be exceptional. According to Zhu’s general sampling theorem is it enough to sample the output signal at the Nyquist rate of the input. However, even though the required sampling rate is reduced the demands on the analog bandwidth remains. Unfortunately, commercially available instruments such as vector signal analyzers can not be used for this purpose since their analog bandwidth is too small. In this paper a test-bed is designed to utilize the Zhu’s general sampling theorem. The RF front-end has frequency range of 500 MHz – 2.7 GHz and a bandwidth of 1 GHz. All performance data are verified with measurements.

  • 11.
    Andersen, Olav
    et al.
    Ericsson AB, Gävle Sweden.
    Wisell, David
    Ericsson AB, Gävle, Sweden.
    Keskitalo, Niclas
    Ericsson AB, Gävle, Sweden.
    Stenvard, Patrik
    Ericsson AB, Gävle, Sweden.
    Cost effective high performance modular instrumentation, signal generation and signal analysis for future mobile communication systems2007In: 2007 IEEE Autotestcon: proceedings. Vol. 1 AND 2, 2007, 660-668 p.Conference paper (Refereed)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing of mobile communication systems. The rapid development and edge technology requires high performance instruments and state of the art measurement technology. It is desired to use virtual/synthetic instruments and put the measurement technology in software independent of hardware, i.e. software driven measurements. Increased flexibility and modularization, both in hardware and software, are requirements to support the cost decrease. The hardware basis is signal generation and signal analysis.

    In this paper state of the art signal generation and signal analysis capabilities are demonstrated in a modular and flexible architecture. A direct IF synthesis is used to generate 1 WideBand Code-Division Multiple Access (WCDMA) carrier with more than 72 dB Adjacent Carrier Leakage Ratio (ACLR) 2 carrier with more than 68 dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities, ACLR performance, for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical down converter in the set up doesn’t degrade the performance.

  • 12.
    Andersen, Olav
    et al.
    Ericsson Telecom AB, Gävle, Sweden.
    Wisell, David
    Ericsson Telecom AB, Stockholm, Sweden.
    Staenvard, Patrik
    Ericsson Telecom AB, Gävle, Sweden.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Extending the Bandwidth and Dynamic Range of Old RF Instruments to Meet State-of-the-Art Performance, Using a Synthetic Instrument Approach2009In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 58, no 2, 248-254 p.Article in journal (Refereed)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing mobile communication systems. The rapid development and edge technology requires high-performance instruments and state-of-the-art measurement technology. New investments are expensive, but even older generation instruments are capable of extending their bandwidth and dynamic range to meet even the latest Third-Generation Partnership Project (3GPP) cellular measurement requirements by the addition of external hardware using a synthetic instrument approach. The novelty of this paper is the high performance on the most crucial parameters, i.e., the dynamic range and bandwidth achieved by only replacing some parts of the legacy instrument. Moreover, the demonstrated direct IF synthesis has a high degree of novelty at wide modulation bandwidths. It is desired to use virtual/synthetic instruments and make the signal processing in the software independent of the hardware, i.e., software-defined measurements (SDMs). In this paper, a state-of-the-art experimental setup for signal generation and signal analysis is demonstrated. A direct IF synthesis is used to generate a wideband code-division multiple-access (WCDMA) carrier with more than 72-dB adjacent carrier leakage ratio (ACLR) up to 12 parallel carriers with more than 68-dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities (e.g., ACLR performance) for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical RF downconverter in the setup is carefully designed not to degrade the dynamic range performance.

  • 13.
    Andersson, Daniel
    et al.
    Radarbolaget, Gävle.
    Wallin, Kjell
    Radarbolaget, Gävle.
    Javashvili, Otar
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Beckman, Claes
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    M-Sequence UWB Radar for Industrial Applications2010In: Program of GigaHertz Symposium 2010, March 9-10, at Lund University, 2010Conference paper (Other academic)
    Abstract [en]

    Ultra Wideband Radar has the potential of dramatically improving the control and surveillance of industrial processes in confined areas. An example is the application of UWB radar for surveillance of furnaces for heath treatment of steel billets developed by Radarbolaget in Gävle.

    In our installation at AB Sandvik Materials Technology, we have shown that by using a non-destructive UWB Radar technique it is possible to visualize in real-time the ongoing process inside the furnace behind a 0.5 m thick ceramic wall. Since the operating temperature inside the furnace is 1200 °C, there is today no other known method capable of visualizing the process for the operator of the furnace. The system is therefore designed to sustain high temperatures and powerful electromagnetic disturbances while performing measurement with wide dynamics and high stability.

    The design of this radar is based on the idea of transmitting a continuous m-sequence and then detecting the correlated impulse response (see figure below). The wide bandwidth is a requirement for obtaining high spatial accuracy and resolution but puts further requirements on the design of the antennas and the electronics. Our results show that with this technique it is possible to determine the deformation of the steel billets inside the furnace with an accuracy of less than 5 mm. The radar system is also able to detect deformations in the furnace wall

    The m-sequence radar has many advantages over other UWB radar technologies since it e.g. does not require many analogue components. Its performance is a result of the choice of code length, sampling rate and averaging. However, the resolution is still limited by the impulse response of the analogue antenna (ringing).

    In this paper system parameters that affect the overall performance of an m-sequence radar are reviewed and means of enhancing its performance are discussed.

  • 14.
    Andersson, Tommy
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Department of Technology and Built Environment.
    Algilany, Gazwan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Department of Technology and Built Environment.
    Konstruktion Signalgenerator2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple signal generator that can provide a pulse modulated signal. The need to buy a new advanced signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a signal generator in accordance with what SAAB requests.

    This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the signal generator.

    What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board. Simulation was done both in software and on laboration board. The card is then ordered from a circuit board manufacturer in Bulgaria. On the finished card the components will be fitted. Then the card will plugged in into a rack and then presented finished as a signal generator that can be used in a test system.

    The final results of all phases are satisfactory in the part of design and laboratory work. The finished mother board was tested and test results corresponded well with the theory. The final results will be presented with a spoken presentation at the University of Gävle and at SAAB Aerotech in Arboga division FGR

  • 15.
    Antón, Raul
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Department of Mechanical Engineering, TECNUN, University of Navarra, Navarra, Spain; Division of Applied Thermodynamics and Refrigeration, KTH Energy Technology, Royal Institute of Technology, Stockholm, Sweden.
    Jonsson, Hans
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Division of Applied Thermodynamics and Refrigeration, KTH Energy Technology, Royal Institute of Technology, Stockholm, Sweden.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Detailed CFD Modelling of EMC Screens for Radio Base Stations: A Parametric Study2009In: IEEE transactions on components and packaging technologies (Print), ISSN 1521-3331, E-ISSN 1557-9972, Vol. 32, no 1, 145-155 p.Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to make a parametric study of the hydraulic resistance and flow pattern of the flow after an electromagnetic compatibility screen and between two printed circuit boards (PCBs) in a model of a 90 degrees subrack cooling architecture. The parametric study is carried out using a detailed 3-D model of a PCB slot. The detailed model was experimentally validated in a previous paper by the authors. Seven parameters were investigated: velocity, inlet height, screen porosity, PCB thickness, distance between two PCBs, inlet-screen gap and screen thickness. A correlation for the static and dynamic pressure drop, the percentage of dimensionless wetted area, A(omega)*, and the RMS* factor (a function of the How uniformity along the PCB) after the screen is reported as a function of six geometrical dimensionless parameters and the Reynolds number. The correlations, that are based on 174 three dimensional simulations, yield good results for the total pressure drop, in which the values are predicted within the interval of +/- 15%. For the, A(omega)*, all the predicted values are within the interval of +/- 22% of the observed values. Finally, for the RMS* factor, the majority of the values also have a disagreement of less than 20% of the observed values. These last two parameters are believed to provide a correct insight about the flow pattern after the screen.

  • 16.
    Apicella Fernández, Sergio
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    MEASUREMENT OF DIELECTRIC CONSTANT FOR WATER AND ITS TEMPERATURE DEPENDENCE AT 0 AND 86ºC2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The dielectric properties determine the electrical characteristics of materials. These properties are important for understanding the behavior of materials and how they can interact with each other. Engineers and scientists need to measure these parameters as accurately as possible, and thus be able to integrate them in their designs in a reliably way.

     

    Examples of application are dielectrics used in capacitors that have the function of reducing the applied electric field and increase the capacitors´ capacitance. The later can be increased by using dielectrics with high permittivity (dielectric constant) as water which has a dielectric constant of 80 at room temperature (25ºC). Unfortunately water cannot be used alone as dielectric due its capacity to be conductive and has to be combined with other materials.

    However, this study will focus only on measuring the dielectric properties of water and its temperature dependence. Temperatures chosen for measurements are 0 and 86ºC.

     

    Several methods have been studied over the years to measure the dielectric properties of materials, but there are only three possible measurement methods for liquids: coaxial probe, parallel plates and free space method. Comparing the three methods, in our case the free-space method is better because it allows to perform measurements at high temperatures and in hostile environments. These two features are very important, since the water should be measured at 86 ºC and measurements are performed in a RF (Radio Frequency) lab, where interferences due to the electronic devices can affect accuracy in free-space measurements.

     

    Hence, the following thesis is based exclusively on analyzing the free-space measurement method for measuring the reflection parameters in dB by using two horn antennas. Both antennas are connected to the Vector Network Analyzer (VNA): one as transmitter and the other as receiver. Reflection parameters are also calculated by introducing the reflection formula for lossless material and a finite length in Matlab. Then, the dielectric constant is extracted by comparing both reflections in dB. 

  • 17.
    Bashir, Babar
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Designing of High Reflectance Distributed Bragg reflectors (DBRs),mirrors using AlGaInN material system in the UV wavelength range2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 18.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Center for RF-Measurement Technology2008In: Radio Science and Communication, RVK08, 2008Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    In February 2006 the Centre for RF Measurement Technology was established at the University of Gävle (HIG). The long term objectives of the centre are to establish world leading research in the area of RF Measurement Technology, support education of radio engineers for local, national and international radio companies at HIG, become a natural collaboration partner for leading industry companies and universities and to support local and national small and middle sized companies in the radio business.

    Today the centre has collaboration with more than 15 national and international companies within 3 major projects in the field of RF measurement technology research spanning from power amplifiers and antennas to electromagnetic interference in industrial environments.

    The annual research budget is in the area of 10 MSEK. In addition to the research projects the centre also supports education and collaboration with local industry, high schools and community.

    The centre is located easy to find, well equipped laboratories in Gävle Technology Park, next to the University of Gävle campus.

  • 19.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Eklund, Lars
    Karlsson, Bo
    Lindmark, Björn
    Ribbenfjärd, David
    Wirdemark, Per
    Verifying 3G licence requirements when every dB is worth a billion2006In: First European Conference on Antennas & Propagation: EuCAP 2006 / [ed] H. Lacoste & L. Ouwehand, 2006, 1-4 p.Conference paper (Refereed)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator: “Post&Telestyrelsen”, PTS, granted in a “beauty contest” four licenses for operations of 3G systems. To verify the coverage and the license requirements, PTS, has developed a test procedure where the field strength of the primary Common Pilot Channel, CPICH, is measured in a drive test. Designing such a test constitutes a number of challenges mainly due to the fact that in 3G the accuracy in the measurement needs to be extremely high since even a small systematic error of ~1dB could in Sweden have the consequence that each operator would have to build an extra +1000 sites at a staggering cost of ~1billion SEK!

    The present paper gives an overview of the considerations behind the design of the test method used for verification of the 3G licence requirements in Sweden.

  • 20.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    Base station antennas for mobile communications2007In: 2007 IEEE International Symposium on Antennas and Propagation: Short Courses & Workshops, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    This course gives the participants a general overview of the application, implementation and design of current and future base station antennas for mobile communications. It is aimed at microwave, RF- and antenna engineers in the wireless area, but also useful for researchers looking for relevant research topics and system engineers needing a deeper understanding of the antenna component of their system. The course explains underlying theoretical and practical implementation aspects of base station antennas in mobile communication networks of today and the future.

    The course is divided into three main parts:

    (i) System Aspects,

    (ii) BTS Antenna Design,

    (iii) Diversity and MIMO

    In the first part the fundamental parameters of a base station antenna are discussed in the context of radio network design. In particular we discuss parameters such as gain, radiation patterns, frequency bands and power handling and put them in the context of cell planning, propagation and capacity.

    In the second part a general overview of base station antenna design is given. In particular the design aspects of radiators, feed networks and reflectors are discussed. Furthermore, a general discussion of array synthesis for base station antennas is given.

    In the final part of the course we give an overview of the underlying theory of diversity and MIMO systems. In particular we discuss the requirements that these systems put on the base station antennas in order to be able to deliver the data rates expected from WiMAX and the long term evolution of 3G systems.

  • 21.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    The evolution of base station antennas for mobile communications2007In: International Conference on Electromagnetics in Advanced Applications: ICEAA 07, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    During the last two decades, mobile telephony has virtually exploded around the world. Whereas fixed telephony has merely around 800 milion phone lines globally, cellular mobile telephony has today close to 4 bilion subscribers less than 20 years after the introduction of digital mobile telephony!

    In the centre of a mobile cell is the base station antenna whose vertical and horizontal beam pattern creates the borders. The first base station antennas deployed for cellular communications were omni-directional in the horizontal plane. These antennas are typically based on stacked circular dipole elements fed by a series feed network. However, as the need for capacity increased more radio channels were being used and the radio networks soon reconfigured to 3 sector systems. The base station antennas in these type of systems typically has half power beam widths in the horizontal plane of around 65 degrees and the elements are fed by corporate feed networks.

    Through the choice of antenna length and the selection of vertical element positions and excitations a broad range of antenna gains and vertical beam patterns can be achieved. We show that for a linear array the gain is mainly determined by the vertical and horizontal beam widths but reduced by losses in the feed network. The electrical down tilt is needed to provide good coverage within the desired cell and is preferred to mechanical down tilt as it is independent of horizontal angle. Remotely adjustable electrical down tilt is also available today and an important cost saver during the expansion part of a network. As we will see, system requirements on reduced channel interferencemlead to a simple expression for the necessary phase shift in such an array.

    Due to the rapid increase in subscribers it was soon realized by the regulators around the world that one frequency band for digital mobile communications was not enough to provide the capacity needed. Therefore, in the mid 90-ties second frequency bands were introduced in both North America and Europe. Since operators are not keen to put up bigger towers and more antennas, ´this development called for dual-band antennas. The introduction of the UMTS band in the beginning of this millennium of course then called for triple band functionality!

    Traditionally the diversity is achieved by using two receive antenna branches separated in space. In mobile phone networks, all base stations for macro cellular communications incorporate diversity on the up-link. Otherwise it would be virtually impossible to communicate with a low power mobile over the rapidly fading channel. Since space diversity uses two horizontally separate antennas positioned about 20 wavelengths apart it become soon of interest for the operators to incorporate polarization diversity. With polarization diversity only one dual polarized antenna is used for each sector at the base. In order to ensure good polarization diversity it is necessary and sufficient to have symmetrical patterns with equal power in horizontal and vertical polarization.

    In 3G it is of great interest to strengthen the up- and down-links in order to be able to increase the data rates from today’s 16kbit/s (voice) to a wireless broadband of around 10Mbits/s. However, in the Long Term Evolution of 3G, LTE, data rates of up to and around 100MBits/s are expected. In order accomplish this diversity at the base station will not be enough but complemented by multiple branch reception and transmission at both the base station and the mobile terminal (Multiple-Input-Multiple-Output, MIMO systems). For such arrays it is of interest to reduce the mutual coupling between elements. Although the mutual coupling could be compensated for by perfect channel estimation it is still of interest to reduce the coupling in practice in order to be able to handle the mismatch loss. In order to do so the use of e.g. corrugations, hard and soft surfaces as well as Electronic Band Gap, EBG materials for the inclusion into the antenna structure has been studied.

    In conclusion we find that the base station antenna has developed dramatically during the last two decades and base station antenna technology may become a key enabler for the Long Term Evolution of 3G.

  • 22.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    Shared Networks: More than making wireless communication affordable2005In: Vehicular Technology Conference, 2005: VTC 2005-Spring., 2005, 2984-2988 p.Conference paper (Refereed)
    Abstract [en]

    In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of license fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this inhibits competition, slow build-out, or otherwise result in reduced consumer benefits. The authors believe that the generic product life-cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact, is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.

  • 23.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    The Benefits of network Sharing2005In: Radiovetenskap och Kommunikation: RVK 2005, 2005, 147-151 p.Conference paper (Other academic)
  • 24.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Design and Characterization of RF-Power LDMOS Transistors2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In mobile communication new applications like wireless internet and mobile video have increased the demand of data-rates. Therefore, new more wideband systems are being implemented. Power amplifiers in the base-stations that simultaneously handle these wideband signals for many terminals (handhelds) need to be highly linear with a considerable band-width.

    In the past decade LDMOS has been the dominating technology for use in these RF-power amplifiers. In this work LDMOS transistors possible to fabricate in a normal CMOS process have been optimized and analyzed for RF-power applications. Their non-linear behavior has been explored using load-pull measurements. The mechanisms of the non-linear input capacitance have been analyzed using 2D TCAD simulations. The investigation shows that the input capacitance is a large contributor to phase distortion in the transistor.

    Computational load-pull TCAD methods have been developed for analysis of RF-power devices in high-efficiency operation. Methods have been developed for class-F with harmonic loading and for bias-modulation. Load-pull measurements with drain-bias modulation in a novel measurement setup have also been conducted. The investigation shows that the combination of computational load-pull of physical transistor structures and direct measurement evaluation with modified load-pull is a viable alternative for future design of RF-power devices. Simulations and measurements on the designed LDMOS shows a 10 to 15 % increase in drain efficiency in mid-power range both in simulations and measurements. The computational load-pull method has also been used to investigate the power capability of LDMOS transistors on SOI. This study indicates that either a low-resistivity or high-resistivity substrate should be used in manufacturing of RF-power LDMOS transistors on SOI to achieve optimum efficiency. Based on a proper substrate selection these devices exhibit a 10 % higher drain-efficiency mainly due to lower dissipated power in the devices.

  • 25.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Integration and Analysis of RF-Power LDMOS Transistors2006Licentiate thesis, comprehensive summary (Other academic)
  • 26.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Johansson, Ted
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Rydberg, Anders
    Optimization of High-Voltage RF Power SiGe Transistors for Cellular Applications1999In: High Power Microwave Electronics: Measurements, Identification, Applications, 1999. MIA-ME '99. Proceedings of the IEEE-Russia Conference, 1999Conference paper (Refereed)
    Abstract [en]

    The base profile design for high-voltage RF power silicon transistors with epitaxial SiGe base was studied using 2-D process and device simulations. The addition of Ge in the base makes thin base widths with very high base doping possible. This gives rise to a higher maximum oscillation frequency thus improving the critical power gain for these devices

  • 27.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Litwin, Andrej
    Olsson, Jörgen
    Small Signal and Power Evaluation of Novel BiCMOS Compatible, Short Channel LDMOS Technology2003In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 51, no 3, 1052-1056 p.Article in journal (Refereed)
    Abstract [en]

    We describe a very short-channel 0.15-mum LDMOS transistor with a breakdown voltage of up to 60 V, manufactured in a standard 0.35-mum BiCMOS process. At 1900 MHz and a 12-V supply voltage, the 0.4-mm-gatewidth device with shortest drain drift region gives 100-mW output power P-1 dB at a drain efficiency of 43%. It has a transducer power gain of over 20 dB. The maximum current gain cutoff frequency f(T) is 15 GHz, and the maximum available gain cutoff frequency f(MAX) is 38 GHz. We show the dependence of f(T), an f(MAX) of gate and drain bias for transistors with different-drain drift region length. The LDMOS process module does not affect the performance or the models of other devices. We present for the first time a simple way to create high-voltage high-performance LDMOS transistors for an RF power amplifier use even in a very downscaled silicon technology.

  • 28.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    A Method for Device Intermodulation Analysis from 2D, TCAD Simulations using a Time-domain Waveform Approach2006In: Proceedings of the 36th European Microwave Conference, 2006, 169-171 p.Conference paper (Refereed)
    Abstract [en]

    This paper describes a fast method useful for IMD analysis at TCAD design level. The method is based on the static load-line transfer function extracted from 2D device simulations. The transfer function is exposed to a time domain signal through a look-up table and the output response is analyzed using the Fast Fourier Transform. The response is compared to measurements of a fabricated device. The method is shown to accurately predict the IMD behavior of a two-tone signal for the 3’rd, 5’th and 7’th order IMD products with regards to sweet spot tracking and relative IMD magnitude. We present a fast and simple way to predict IMD performance from TCAD simulations at an early stage in the design process. The method enables prediction of output response from any signal due to the time domain approach.

  • 29.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    FTE Uppsala Universitet.
    Olsson, Jörgen
    FTE Uppsala Universitet.
    A Computational Load-Pull Investigation of Harmonic Loading effects on AM-PM conversion2008In: GigaHertz Symposium 2008: Abstract Book, 2008, 83-83 p.Conference paper (Other academic)
    Abstract [en]

    In this work computational harmonic load-pull have been used to study the effect of harmonic loading on AM-PM conversion for an RF-Power LDMOS transistor. It is found that especially the load impedance seen at the 2nd harmonic has a large impact (up to 2° or 15% difference) on the phase distortion at P1dB in this investigation conducted at chip level.

  • 30.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    FTE Uppsala.
    Olsson, Jörgen
    FTE Uppsala.
    A Computational Load-Pull Method for TCAD Optimization of RF-Power Transistors in Bias-Modulation Applications2008In: 2008 European Microwave Integrated Circuits Conference (EuMIC), 2008, 222-225 p.Conference paper (Refereed)
    Abstract [en]

    Abstract— In this paper a method for TCAD evaluation of RF-Power transistors for high-efficiency operation using drain bias-modulation is presented. The method is based on large signal time-domain transient computational load-pull. With the method, intrinsic device parasitics and mechanisms affecting device efficiency under drain bias modulation can be investigated and optimized for the application making it very useful for RFIC design. A case study has been done on a CMOS compatible LDMOS. For verification under dynamic operation two-tone signals with varying envelope has been simulated. The results show a possible 15% increase in the efficiency of a modulated signal for the studied device at the expense of increased phase distortion observable also in the time-domain waveforms generated. Since the method is based on TCAD it is also useful in the investigation of e.g. dynamic breakdown during high envelope under bias-modulation operation.

  • 31.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    The Ångström Laboratory, Solid State Electronics, Uppsala University, Uppsala, Sweden.
    Olsson, Jörgen
    The Ångström Laboratory, Solid State Electronics, Uppsala University, Uppsala, Sweden.
    A Computational Load-Pull Method with Harmonic Loading for High-Efficiency Investigations2009In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 53, no 1, 86-94 p.Article in journal (Refereed)
    Abstract [en]

    In this paper a method for TCAD evaluation of RF-power transistors in highefficiency operation using harmonic loading is presented. The method is based on large signal timedomain

    computational load-pull. Active loads are used in the harmonic load-pull for simulation time reduction. With the method device performance under different harmonic load impedance can

    be investigated at an early stage in the design process. Alternative designs can be compared and the mechanisms affecting device efficiency in class-F can be studied at chip level. For method validation a case study is made on an LDMOS transistor. The transistor is load-pulled in class-AB and then optimized for efficiency at 2f0 and 3f0 using a novel approach with passive fundamental load and active harmonic loads. A swept simulation is conducted using passive fundamental and

    harmonic loads. Waveforms in compression are analyzed and the mechanisms creating the increased efficiency for in class-F are indentified by a comparative study of class-AB. Class-F harmonic termination is shown to give a 17 % overall reduction of dissipated power and a 9 % increase in output power. The expected efficiency increase is about 3-10 % in the compression

    region depending on level of compression.

  • 32.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    Solid State Electronics, Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Olsson, Jörgen
    Solid State Electronics, Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Investigation of SOI-LDMOS for RF-Power Applications Using Computational Load Pull2009In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 56, no 3, 505-511 p.Article in journal (Refereed)
    Abstract [en]

    Small-signal and computational load-pull simulations are used to investigate the effect of substrate resistivity on efficiency in high-power operation of high-frequency silicon-on insulator-LDMOS transistors. Identical transistors are studied on substrates with different resistivities. Using computational load pull, their high-power performance is evaluated. The results are compared to previous investigations, relating the OFF-state out put resistance to high-efficiency operation. From the large-signal simulation, an output circuit model based on a load-line match is extracted with parameters traceable from small-signal simu lations. It is shown that, albeit high OFF-state output resistance is a good indication, it is not sufficient for high efficiency in a high-power operation. The bias and frequency dependence of the coupling through the substrate makes a more detailed ON-state analysis necessary. It is shown that very low resistivity and high resistivity SOI substrates both result in a high efficiency at the studied frequency and bias point. It is also shown that a normally doped medium-resistivity substrate results in a significantly lower efficiency.

  • 33.
    Bengtsson, Olof
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Vestling, Lars
    The Ångström Laboratory, Solid State Electronics, Uppsala University, Uppsala, Sweden.
    Olsson, Jörgen
    The Ångström Laboratory, Solid State Electronics, Uppsala University, Uppsala, Sweden.
    Investigation of the Nonlinear Input Capacitance in LDMOS Transistors and its Contribution to IMD and Phase Distortion2008In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 52, no 7, 1024-1031 p.Article in journal (Refereed)
    Abstract [en]

    In this paper the mechanisms causing the capacitive, reactive non-linearities in a lateral double diffused MOS, LDMOS, transistor are investigated. The non-linear input capacitance under load-line power match is extracted and analyzed. Computational TCAD load-pull is used to analyze the effect of non-linear capacitance on two-tone intermodulation distortion and AM–PM conversion in class-A operation. High-frequency measurements have been made to verify the use of 2D numerical device simulations for the analysis. It is found that the input capacitance, Cgg, of the LDMOS transistor working under power match conditions is a strongly non-linear function of gate voltage Vg but with an almost linear initial increase in Cgg. The voltage dependence of Cgg is found to mainly affect higher order IMD products in class-A operation. Transient simulations however show that Cgg seriously contributes to the onset of AM–PM conversion well below the 1 dB compression point.

  • 34.
    Berg, Henrik
    et al.
    Faculty of Computer Sciences, Østfold University College, Halden, Norway.
    Olsson, Roland
    Faculty of Computer Sciences, Østfold University College, Halden, Norway.
    Lindblad, Thomas
    Royal Institute of Technology, Department of Physics, Stockholm, Sweden.
    Chilo, José
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Automatic design of pulse coupled neurons for image segmentation2008In: Neurocomputing, ISSN 0925-2312, E-ISSN 1872-8286, Vol. 71, no 10-12, 1980-1993 p.Article in journal (Refereed)
    Abstract [en]

    Automatic Design of Algorithms through Evolution (ADATE) is a program synthesis system that creates recursive programs in a functional language with automatic invention of recursive help functions and self-adaptive optimization of numerical values. We implement a neuron in a pulse coupled neural network (PCNN) as a recursive function in the ADATE language and then use ADATE to automatically evolve better PCNN neurons for image segmentation. Our technique is generally applicable for automatic improvement of most image processing algorithms and neural computing methods. It may be used either to generally improve a given implementation or to tailor that implementation to a specific problem, which with respect to image segmentation for example can be road following for autonomous vehicles or infrared image segmentation for heat seeking missiles that are to distinguish the heat source of the target from flares.

  • 35.
    Bergstrand, Marcus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Datainsamlingssystem för underhåll och kontroll av elkvalitet2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    SSAB i Borlänge ska byta ut deras befintliga loggsystem som övervakar elkvalitet på verkets fem huvudtransformatorer. Loggsystemen ska ersättas med modulära DAQsystem från Iba, vilket är system som redan används i flera av verkets processer. Syftet med arbetet är att visa hur de nya DAQ-systemen kan implementeras och målet är att skapa förutsättningar för felsökning vid elkvalitetstörningar och analys av eltillförseln. Rapporten beskriver hur två utdömda loggsystem ersätts mot ett modulärt DAQ-system under skarp drift, som sedan konfigureras enligt önskad funktion. Tillvägagångssättet innefattar tre större delar vilka är datainsamling, hårdvarukonstruktion och mjukvarukonfiguration. Datainsamlingen har till stor del varit att studera befintliga kretsscheman och manualer till systemets hård- och mjukvara. Informationen som samlades in gav förutsättningarna för konstruktionsarbetet och mjukvarukonfigurationer. Utgången blev ett driftsatt system som konfigurerades så att felsökning och analys av elkvalitet är möjlig. Det nya loggsystemet gör det även möjligt för fler användare att komma åt mätningar kring elkvalitetsstörningar. Användare kan sedan ställa dessa i korrelation till de mätningar som utförs med iba-system vid processerna.

  • 36.
    Björklund, Johan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    PLC Back-up system2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis was to investigate the PLC systems used in ABBs breaker factory in Ludvika and to create a system specification suitable to be used in the procurement of a back-up solution for this workshop.

    This work involved information gathering from different sources, such as archives, physical installations and interviews of maintenance personnel and operators.

    The results included the requested system specification (in Swedish) including suggestions for pilot test installations and evaluations. The work also resulted in an extensive listing of all PLC systems with placement, typedesignations, expansion modules and other pertinent information. This information ismade available as a macro enabled multipage Microsoft Excel document.

    A summary and suggestions for follow up work is also included.

  • 37.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Modeling analog to digital converters at radio frequency2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This work considers behavior modeling of analog to digital converters with applications in the radio frequency range, including the field of telecommunication as well as test and measurement instrumentation, where the conversion from analog to digital signals often is a bottleneck in performance. The models are intended to post-process output data from the converter and thereby improve the performance of the digital signal. By building a model of practical converters and the way in which they deviate from ideal, imperfections can be corrected using post-correction methods.

    Behavior modeling implies generation of a suitable stimulus, capturing the output data, and characterizing a model. The demands on the test setup are high for converters in the radio frequency range. The test-bed used in this thesis is composed of commercial state-of-the-art instruments and components designed for signal conditioning and signal capture. Further, in this thesis, different stimuli are evaluated, theoretically as well as experimentally.

    There are a large number of available model structures for dynamic nonlinear systems. In order to achieve a parameter efficient model structure, a Volterra model was used as a starting-point, which can describe any weak nonlinear system with fading memory, such as analog to digital converters. However, it requires a large number of coefficients; for this reason the Volterra model was reduced to a model structure with fewer parameters, by comparing the symmetry properties of the Volterra kernels with the symmetries from other models. An alternative method is the Kautz-Volterra model, which has the same general properties as the Volterra model, but with fewer parameters. This thesis gives experimental results of the Kautz-Volterra model, which will be interesting to apply in a post-correction algorithm in the future.

    To cover behavior not explained by the dynamic nonlinear model, a complementary piecewise linear model component is added. In this thesis, a closed form solution to the estimation problem for both these model components is given. By gradually correcting for each component the performance will improve step by step. In this thesis, the relation between a given component and the performance of the converter is given, as well as potential for improvement of an optimal post-correction.

  • 38.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Daponte, Pasquale
    Department of Engineering, University of Sannio, Italy.
    De Vito, Luca
    Department of Engineering, University of Sannio, Italy.
    Rapuano, Sergio
    Department of Engineering, University of Sannio, Italy.
    Automatic signal recognition for a flexible spectrum management2009In: XIX IMEKO World Congress, 2009, 568-573 p.Conference paper (Refereed)
    Abstract [en]

    The paper presents the prototype of an automatic digital modulation classifier, to be used for signal recognition in frequency bands managed in a flexible way. The prototype is based on a Data Acquisition System, consisting of an Analog-to-Digital converter embedded in an evaluation board, a frame grabber and a Personal Computer. The modulation classifier is able to recognize the most used digital modulations. An experimental validation of the realized prototype in a radio environment is also provided.

  • 39.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    Signal Processing Lab., ACCESS Linnaeus Center, School of Electrical Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Achievable ADC Performance by Postcorrection Utilizing Dynamic Modeling of the Integral Nonlinearity2008In: EURASIP Journal on Advances in Signal Processing, ISSN 1687-6172, E-ISSN 1687-6180, 497187Article in journal (Refereed)
    Abstract [en]

    There is a need for a universal dynamic model of analog to digital converters (ADC) aimed for post-correction. However, it is complicated to fully describe the properties of an ADC by a single model. An alternative is to split up the ADC model in different components, where each component has unique properties. In this paper, a model based on three components is used, and a performance analysis for each component is presented. Each component can be post-corrected individually and by the method that best suits the application. The purpose with post-correction of an ADC is to improve the performance. Hence, for each component, expressions for the potential improvement have been developed. The measures of performance are total harmonic distortion (THD) and signal to noise and distortion (SINAD) and to some extent spurious free dynamic range (SFDR).

  • 40.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    Royal Institute of Technology, Stockholm.
    Dynamic behavior models of analog to digital converters aimed for post-correction in wideband applications2006In: IMEKO Workshop on ADC and DAC Modelling and Testing, September 17-22, 2006, Rio de Janeiro, 2006, 5- p.Conference paper (Refereed)
    Abstract [en]

    In this paper a dynamic behavior model of analog to digital converters is proposed. The model is aimed for post correction in wideband applications. The suggested post correction method is a combination of look up tables and model based correction. The model consists of three components. The first is a component represented by a Hammerstein model; that is a static nonlinearity followed by a time invariant linear filter. The second component is a nonparametric model caused by significant deviation from the characterized integral nonlinearity and the output from the Hammerstein model. The third component contains of the remaining deviation and is considered as a random model error. Results from simulations verify that the examined ADC can be described by an ordinary Hammerstein model and a static look-up table.

  • 41.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    Signal Processing Laboratory, Royal Institute of Technology, Stockholm, Sweden.
    Histogram Tests for Wideband Applications2008In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 57, no 1, 70-75 p.Article in journal (Refereed)
    Abstract [en]

    Characterization and testing of analog-to-digital converters (ADCs) are important in many different aspects. Histogram test is a common method to characterize the linearity features of an ADC. Two commonly used stimuli signals are sine waves and Gaussian noise. This paper presents a metrological comparison between Gaussian and sine wave histogram tests for wideband applications; that is we evaluate the performance in characterization of the ADC and the usability of post-correction. A post-correction procedure involves characterization of the ADC non-linearity and then use of this information by processing the ADC output samples to remove the distortion.

    The results show that the Gaussian histogram test gives reasonable accuracy to measure non-linearities. However, it does not result in a suitable model for post-correction in wideband applications. A single-tone sine wave histogram will be a better basis for post-correction. Best result can be obtained if the look-up table is trained with several single-tone sine waves in the frequency band.

  • 42.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Post-Correction of Under-Sampled Analog to Digital Converters2007In: IEEE Instrumentation and Measurement Technology Conference, 2007Conference paper (Refereed)
    Abstract [en]

    Applications with wide bandwidth and high center frequencies force the analog to digital converter (ADC) to be active in a working range with less dynamic performance in relation to lower frequency bands. However using under-sampling techniques in combination with post-correction methods enable a combination of high sampling rate, wide bandwidth and low distortion. In this paper the employed dynamic post-correction is a combination of look-up tables and model based correction. The results are mainly based on measurements on a 12 bit 210 MSPS ADC. The improvement in total harmonic distortion and spurious free dynamic range are acceptable over a wide frequency range and it is robust to variations in amplitude.

  • 43.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    Royal Institute of Technology, Signal Processing Laboratory, Stockholm, Sweden.
    Truncated Gaussian noise in ADC histogram tests2007In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 40, no 1, 36-42 p.Article in journal (Refereed)
    Abstract [en]

    One method to characterize analogue to digital converters (ADCs) is to use a histogram, where Gaussian noise may be used as stimulus signal. However, a Gaussian noise signal that excites all transition levels also generates input values outside working range of the ADC. Modern signal generators can generate arbitrary signals. Hence, excluding undesired values outside the ADC full scale can minimize test sequences. Truncating the signal to the working range gives further advantages, which are explored in this paper. The Cramér-Rao lower bound and a minimum variance estimator for histogram tests with an arbitrary stimulus are derived. These are applied for truncated Gaussian noise and the result is theoretically evaluated and compared to untruncated noise. It is shown that accuracy increases for a fixed sample length and that variation over transition levels decrease.

  • 44.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Kautz-Volterra modelling of an analogue-to-digital converter using a stepped three-tone excitation2007In: 12th IMEKO TC-4 International Workshop on ADC MODELLING AND TESTING, Iasi, Romania, September 2007, 2007, 107-112 p.Conference paper (Refereed)
  • 45.
    Björsell, Niclas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies. Royal Inst Technol, ACCESS Linnaeus Ctr, Stockholm, Sweden.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies. Royal Inst Technol, ACCESS Linnaeus Ctr, Stockholm, Sweden.
    Händel, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Royal Inst Technol, ACCESS Linnaeus Ctr, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Kautz-Volterra modelling of analogue-to-digital converters2010In: Computer Standards & Interfaces, ISSN 0920-5489, E-ISSN 1872-7018, Vol. 32, no 3, 126-129 p.Article in journal (Refereed)
    Abstract [en]

    In many test and measurement applications, the analogue-to-digital converter (ADC) is the limiting component. Using post-correction methods can improve the performance of the component as well as the over all measurement system. In this paper an ADC is characterised by a Kautz-Volterra (KV) model, which utilises a model-based post-correction of the ADC with general properties and a reasonable number of parameters. It is also shown that the inverse model has the same dynamic properties as the direct KV model. Results that are based on measurements on a high-speed 12-bit ADC, shows good results for a third order model.

  • 46.
    Björsell, Niclas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Sucháneck, Petr
    Department of Measurement, Czech Technical University, Prague, Czech Republic.
    Händel, Peter
    Signal Processing Laboratory, Royal Institute of Technology, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. WesternGeco, Asker, Sweden.
    Measuring Volterra kernels of analog to digital converters using a stepped three-tone scan2008In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 57, no 4, 666-671 p.Article in journal (Refereed)
    Abstract [en]

    Volterra theory can be used to mathematically model nonlinear dynamic components such as analog-to-digital converter (ADC). This paper describes how frequency domain Volterra kernels of an ADC are determined from measurements. The elements of Volterra theory are given and practical issues are considered, such as methods for signal conditioning, finding the appropriate test signals scenario and suitable sampling frequency. The results show that for the used pipeline ADC, the frequency dependence is significantly stronger for second order difference products than for sum products and the linear frequency dependence was not as pronounced as that of the second order Volterra kernel. It is suggested that the Volterra kernels have the symmetry properties of a specific box model, namely a parallel Hammerstein systems.

  • 47.
    Borg, Daniel
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Mantling, Ulf
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Syntetiska Instrument2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to investigate SAAB AB´s possibilities to use synthetic instruments in their test systems. The reason for this is reducing costs and the risk of obsolescence which is common when test systems operate for several decades.

    The market around synthetic instruments has been explored in the search for suitable hardware and software. Software has been developed in LabVIEW and synthetic instruments have been created with the help of IVI-drivers. The hardware consisted of PXI-instruments (Waveform generator and Digitizer), connected to a computer using a fiber optic link and PXI-chassi. The created instruments was then compared to common instruments used today, and the comparison turned out well. Advantages, disadvantages and the theory surrounding synthetic instruments is also covered. This thesis is only an introduction and further work will be necessary to implement synthetic instruments at SAAB.

    The thesis also purposes suitable hardware and further development based on the test systems used today, and how it is possible to solve the layer structure.

  • 48. Castillo, Patricia
    et al.
    San-Roman, Ebert
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    On the design of a planar, harmonic, triplex-filter for 3G, load-pull measurement applications2007In: RFMTC-07, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    This paper describes the design of a planar harmonic triplex-filter for 3G load-pull measurement applications. The designs are based on planar 2D field simulations on individual and combined filters of different structures like stepped impedance, coupled lines and ring resonators. Triplex-filters of different combinations on Teflon substrate and mixed substrates for loss reduction were simulated, fabricated and evaluated in this work. It is found that using lithographic process on Teflon with SMA endlaunchers a filter with 0.44 dB f0 insertion loss, IL, and 50 dB isolation can be achieved. On the low loss substrate the mechanical design process limits the results to about 1.0 dB IL. Low loss launchers and substrate interconnects are suggested and 3D simulations performed for the mixed design.

  • 49.
    Chang, Keke
    et al.
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Chen, Ruipeng
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Wang, Shun
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Li, Jianwei
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Hu, Xinran
    School of Human Nutrition and Dietetics, McGill University, Canada..
    Liang, Hao
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Cao, Baiqiong
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Sun, Xiaohui
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Ma, Liuzheng
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Zhu, Juanhua
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China.
    Jiang, Min
    College of life sciences, Henan Agricultural University, Zhengzhou, China.
    Hu, Jiandong
    Department of Electrical Engineering, Henan Agricultural University, Zhengzhou, China; State key laboratory of wheat and maize crop science, Zhengzhou, China.
    Considerations on Circuit Design and Data Acquisition of a Portable Surface Plasmon Resonance Biosensing System2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 8, 20511-20523 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to develop a circuit for an inexpensive portable biosensing system based on surface plasmon resonance spectroscopy. This portable biosensing system designed for field use is characterized by a special structure which consists of a microfluidic cell incorporating a right angle prism functionalized with a biomolecular identification membrane, a laser line generator and a data acquisition circuit board. The data structure, data memory capacity and a line charge-coupled device (CCD) array with a driving circuit for collecting the photoelectric signals are intensively focused on and the high performance analog-to-digital (A/D) converter is comprehensively evaluated. The interface circuit and the photoelectric signal amplifier circuit are first studied to obtain the weak signals from the line CCD array in this experiment. Quantitative measurements for validating the sensitivity of the biosensing system were implemented using ethanol solutions of various concentrations indicated by volume fractions of 5%, 8%, 15%, 20%, 25%, and 30%, respectively, without a biomembrane immobilized on the surface of the SPR sensor. The experiments demonstrated that it is possible to detect a change in the refractive index of an ethanol solution with a sensitivity of 4.99838 × 10(5) ΔRU/RI in terms of the changes in delta response unit with refractive index using this SPR biosensing system, whereby the theoretical limit of detection of 3.3537 × 10(-5) refractive index unit (RIU) and a high linearity at the correlation coefficient of 0.98065. The results obtained from a series of tests confirmed the practicality of this cost-effective portable SPR biosensing system.

  • 50.
    Chilo, José
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Feature Extraction for Low-Frequency Signal Classification2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The development of the International Monitoring System (IMS) for the verification of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has led to a rapid revival of interest in infrasound. Furthermore, the installation of low-frequency sensors at seismic sites has increased in recent years, providing researchers with large and heterogeneous data-sets in near real-time. New techniques are needed to better process all of this data and to extract meaningful information quickly for various applications. In particular, there is a need to find distinct features in the infrasonic signals that allow one to distinguish low level nuclear tests from seismic events.

    In this thesis three methods for feature extraction from infrasound and other types of low frequency signal data are discussed: (1) discrete wavelets transforms (DWTs); (2) time scale spectra (TSSs) using continuous wavelet transforms (CWTs); and (3) empirical mode decomposition (EMD). The dimensionality of the feature space can range from a few to thousands. For processing high-dimensional data we use multi-modal data space to find low-dimensional structures. The advantage of this space is that multiple metrics of similarity are converted into one single Euclidean space.

    The overall goal of our research is a system for automatic identification and classification of low-frequency signals in real-time that is easy to implement in hardware. In this thesis we present our design and implementation of the discrete wavelet transform (DWT) on FPGAs for processing a continuous flow of data to obtain optimal extraction of feature information. FPGA simulation and implementation has been realized by using the polyphase structure, the filter reuse method and techniques such as pipelining and basic operations on the QUARTUS II platform. VHDL has been used to describe the functionality of the discrete wavelet transform and ModelSim has been used for the functional verification.

    Advancements in electronics provide a vital new option for implementation of low-frequency smart sensors that can perform signal processing close to the sensors and transmit the data wirelessly. These smart sensors can improve the efficiency of an automatic classification system and reduce the cost of actual infrasound microphones. The design of a digital wireless data acquisition system using a QF4512 programmable signal converter from Quickfilter Technologies, a MSP430 microcontroller from Texas Instruments and a F2M03GLA Bluetooth module from Free2move for infrasonic records is also presented in this thesis. The digital wireless data acquisition system has passed extensive laboratory and field tests (e.g. with man-made explosions).

    A study of using a miniature 3-axis fluxgate magnetometer to get fingerprints from ferrous objects is also presented in this thesis. In this experiment, distinguishing features of iron samples of four different shapes were determined using wavelet methods. Systematic differences were observed between the signatures of the four shaped iron samples.

12345 1 - 50 of 208
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf