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  • 151.
    Wisell, David
    et al.
    Ericsson.
    Stenvard, Patrik
    Ericsson.
    Hansebacke, Anders
    Ericsson.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Considerations when Designing Virtual Instruments2009Report (Other academic)
    Abstract [en]

    In this paper the software and hardware structure of a virtual instrument measurement system is discussed. The focus is on flexibility, modularity, generality and hardware independence. A software architecture that meets these requirements is proposed and discussed in some detail. The proposed software architecture has a layered structure that makes it suitable for implementation of versatile measurement systems. The measurement functionality is encapsulated in its own, hardware independent layer and communicates with its environment, e.g. physical hardware, through intermediary software components. Finally a measurement system for characterization of power amplifiers that is designed following the proposed software architecture, with software driven measurements, is implemented.

  • 152.
    Wu, Xing
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    The Survey of Detection Methods and Testbeds For Cognitive Radio Application2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

       The need for RF spectrum for the rapidly growing broadband access services is evident. Cognitive radio is an emerging technology that aims to introduce secondary usage of the spectrum resources without interfering with the primary usage of the licensed users but with a lower priority.

       Signal detection for cognitive radios has drawn a lot of interest in the research community, where different algorithms are suggested. The most commonly used algorithms are energy detection, feature detection, eigenvalue based detection. Energy detection is the simplest and most common way to detect signals. It has fast sensing time but poor performance. The feature detection and eigenvalue based detection methods are more sophisticated and offer better performance but they are more complex and expensive. This thesis will present the pros and cons of each method and offer comparisons between them.

       To evaluate the performance of different algorithms used in cognitive radio, different research testbeds have been suggested in the literature. Some of the most frequently used testbeds are based on GNU-radio, WARP, or BEE2. GNU-radio is the simplest testbed and is free, but it has low bandwidth and poor performance. WARP and BEE2 are more advanced testbeds. They offer good performance and are easy to update, but they are more complex and expensive. These three testbeds will be described, compared, and their advantages and disadvantages will be observed in this thesis.

  • 153.
    Zenteno, Efrain
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    MEASUREMENTS OF SCATTERING PARAMETERSUSING A TIME DOMAIN TEST SETUP2008Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    From its beginning, scattering parameters are one of the most important milestones in radio frequency analysis and device characterization, even though some other instruments are capable of performing such measurements, the task has been almost entirely left to Vector Network Analyzer (VNA).

    The purpose of this work is to emulate VNA functionality for forward measurements (S11 and S21), being able to expand its actual capabilities, using a time domain setup with equipment already available in radio stations, where a personal computer will act as a main processor and interface to the user.

    Hardware setup proposed in this investigation is explained in detail, analyzing its advantages and drawbacks; this as well as software methodology in order to mimic VNA functionality, including error vector correction provided by a suitable calibration procedure.

    Results were compared to those obtained in previous research as well as industrial and well calibrated VNA, showing very good agreement in both cases, where the interpretation of the results is based on repeatability and accuracy analysis.

  • 154.
    Zenteno, Efrain
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Andersen, Olav
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    Nonlinear Network Analysis for Modern Communication Devices and Systems2008In: 72nd ARFTG Conf. Dig., Portland, OR, 2008, p. 64-68Conference paper (Refereed)
  • 155.
    Zenteno, Efrain
    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.
    Wisell, David
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Andersen, Olav
    An Envelope Domain Measurement Test Setup to Acquire Linear Scattering Parameters2008In: 72nd ARFTG Conf. Dig., Portland, OR, 2008, p. 54-57Conference paper (Refereed)
  • 156.
    Zhao , Hai
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lin, Gui
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Study of Couping Element Based Antenna Structure2009Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This thesis presents a study on built-in type low profile and low volume mobile phone antennas. In a coupling element based antenna, the chassis is the main radiator and the antenna elements are the exciters for the wave modes at low frequency. The main work of this thesis is to demonstrate and investigate the performance of the coupling element based antenna and study a variety of cases with different physical lengths and different physical heights. The investigation is done by using simulators. The performance is evaluated by analyzing the impedance bandwidth and the efficiency. For the study, antenna prototypes integrating miniaturized matching circuits were modeled. Two antenna structure prototypes covering five frequency bands were manufactured and measured. The Measured results are presented and compared with simulations. Finally, the performance of the coupling element based antenna is compared with planar inverter-F antenna (PIFA) and discussed.

  • 157.
    Zhao, Hai
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Gui, Lin
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Penta-Band Coupling Element Based Mobile Phone Antenna2009Book (Other academic)
    Abstract [en]

    This thesis presents a study on built-in type low profile and low volume mobile phone antennas. In a coupling element based antenna, the chassis is the main radiator and the antenna elements are the exciters for the wave modes at low frequency. The main work of this thesis is to demonstrate and investigate the performance of the coupling element based antenna and study a variety of cases with different physical lengths and different physical heights. The investigation is done by using simulators. The performance is evaluated by analyzing the impedance bandwidth and the efficiency. For the study, antenna prototypes integrating miniaturized matching circuits were modeled. Two antenna structure prototypes were manufactured and measured. The Measured results are presented and compared with simulations. Finally, the performance of the coupling element based antenna is compared with planar inverter-F antenna (PIFA) and discussed.

  • 158.
    Zhao, Hai
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Lin, Gui
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Claes, Beckman
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Design of a Coupling Element Based Penta-band Mobile Phone Antenna2009In:  Antennas & Propagation Conference, 2009. LAPC 2009. Loughborough, 2009, p. 209-212Conference paper (Refereed)
    Abstract [en]

    Based on the work by Vilanen et al., a small, low profile and efficientcoupling element based antenna with penta-band operations for the use inmobile telephones has been studied. The antenna was designed using the HighFrequency Structure Simulator, HFSS, from Ansoft. Two prototypes withdifferent antenna profile heights have been built, verified and tested. Thebandwidth of the antenna is extended compared to the original design. Alumped element based network is used to optimize the matching. Theresulting antenna operates (|S11|≤-5 dB) from 824 to 1300MHz and from1710 to 2170MHz, covering in total five cellular bands with an efficiencybetter than -3dB and a total volume of less than 4cm3.

1234 151 - 158 of 158
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