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  • 351.
    Lang, Ming-Shuang
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Remote Residential Control System2004Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A remote residential control system enables home users to remotely manage devices at their homes. These devices may include energy management, security surveillance, household appliances, consumer electronics, etc. This system involves technologies in home automation, home networking, and interfacing a home network with external networks. However, lacking a single standard poses a big challenge to the design of such a system. This thesis proposed three methods of turning an IP Set-Top Box into a remote residential control platform. Additionally, future trends are discussed. Various technologies in the fields mentioned above are also examined.

  • 352.
    Lankinen, A.
    et al.
    Optoelectronics Laboratory, Helsinki University of Technology.
    Tuomi, T.
    Optoelectronics Laboratory, Helsinki University of Technology.
    Karilahti, M.
    Optoelectronics Laboratory, Helsinki University of Technology.
    Zytkiewicz, Z. R.
    Institute of Physics, Polish Academy of Sciences.
    Domagala, J. Z.
    Institute of Physics, Polish Academy of Sciences.
    McNally, P. J.
    Research Institute for Networks and Communications Engineering, Dublin City University.
    Sun, Yan-Ting
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Crystal Defects and Strain of Epitaxial InP Layers Laterally Overgrown on Si2006In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 6, no 5, p. 1096-1100Article in journal (Refereed)
    Abstract [en]

    Defects in epitaxial laterally overgrown (ELO) InP layers are examined by high-resolution X-ray diffraction and synchrotron X-ray back-reflection and transmission topography. X-ray diffraction maps produce information about the overall crystal quality of the epitaxial layers in the InP ELO sample. The topographs show small angle boundaries, and the associated dislocations are located at the boundaries between the crystallites; allowing for their relative tilt, the maximum value for this is 0.06 degrees. No defects inside the crystallites can be seen in the topographs, except for a small bending of 0.04 degrees at most, of the ELO lattice planes. The section topographs show deformed X-ray interference fringes resulting from the large strain of the silicon lattice below the seeding areas.

  • 353. Lee, H. L. T.
    et al.
    Ram, R. J.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bandwidth enhancement and chirp reduction in DBR lasers by strong optical injection2000In: Lasers and Electro-Optics, 2000. (CLEO 2000). Conference on, 2000, p. 99-100Conference paper (Refereed)
    Abstract [en]

    We have observed modulation bandwidth enhancement to 28 GHz and evidence of reduced chirp, beyond the optimally tuned free running case, in strongly injection-locked DBR lasers. Bandwidth enhancement occurs because the total modal photon density depends on the phase between the master and slave fields, which varies during modulation due to the dependence of index on carrier density. This results in an increased coupling between the carriers and photons, giving an effectively higher differential gain. This effect appears to be stronger than the similar amplitude-phase coupling that occurs with detuned loading. Chirp reduction occurs only for very strong injection, which can be explained by the fact that chirp reduction can only be achieved for modulation frequencies less than the locking range, which increases with injected power. For higher frequencies, the chirp reduction due to detuned loading dominates

  • 354. Lee, H. L. T.
    et al.
    Ram, R. J.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Enhanced direct modulation efficiency by FM to IM conversion2000In: Microwave Photonics, 2000. MWP 2000. International Topical Meeting on, 2000, p. 105-108Conference paper (Refereed)
    Abstract [en]

    Enhanced modulation efficiency of a directly modulated, high speed DBR laser of up to 400% has been demonstrated using FM to IM conversion in optical fiber. The link noise figure is improved by 8 dB and the dynamic range by 3 dB at 10 GHz

  • 355.
    Lee, Hyung-Seok
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    High power bipolar junction transistors in silicon carbide2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    As a power device material, SiC has gained remarkable attention to its high thermal conductivity and high breakdown electric field. SiC bipolar junction transistors (BJTs) are interesting for applications as power switch for 600 V-1200 V applications. The SiC BJT has potential for very low specific on-resistances and this together with high temperature operation makes it very suitable for applications with high power densities. One disadvantage of the BJT compared with MOSFETs and Insulated Gate Bipolar Transistors (IGBTs) is that the BJT requires a more complex drive circuit with higher power capability. For the SiC BJT to become competitive with field effect transistors, it is important to achieve high current gains to reduce the power required by the drive circuit. Although much progress in SiC BJTs has been made, SiC BJTs still have low common emitter current gain typically in the range 10-50. In this work, a record high current gain exceeding 60 has been demonstrated for a SiC BJT with a breakdown voltage of 1100 V. This result is attributed to an optimized device design, a stable device process and state-of-the-art epitaxial base and emitter layers.

    A new technique to fabricate the extrinsic base using epitaxial regrowth of the extrinsic base layer was proposed. This technique allows fabrication of the highly doped region of the extrinsic base a few hundred nanometers from the intrinsic region. An important factor that made removal of the regrowth difficult was that epitaxial growth of very highly doped layers has a faster lateral than vertical growth rate and the thickness of the p+ layer therefore has a maximum close to the base-emitter sidewall. A remaining p+ regrowth spacer at the edge of the base-emitter junction is proposed to explain the low current gain.

    Under high power operation, the SiC BJTs were strongly influenced by self-heating, which significantly limits the performance of device. The DC I-V characteristics of 4H-SiC BJTs have also been studied in the temperature range 25 °C to 300 °C. The DC current gain at 300 °C decreased 56 % compared to its value at 25 °C. Selfheating effects were quantified by extracting the junction temperature from DC measurements.

    To form good ohmic contacts to both n-type and p-type SiC using the same metal is one important challenge for simplifying SiC Bipolar Junction Transistor (BJT) fabrication. Ohmic contact formation in the SiC BJT process was investigated using sputter deposition of titanium tungsten to both n-type and p-type followed by annealing at 950 oC. The contacts were characterized with linear transmission line method (LTLM) structures. The n+ emitter structure and the p+ base structure contact resistivity after 30 min annealing was 1.4 x 10-4 Ωcm2 and 3.7 x 10-4 Ωcm2, respectively. Results from high-resolution transmission electron microscopy (HRTEM), suggest that diffusion of Si and C atoms into the TiW layer and a reaction at the interface forming (Ti,W)C1-x are key factors for formation of ohmic contacts.

  • 356.
    Lee, Hyung-Seok
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Domeij, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Danielsson, Erik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Zetterling, Carl-Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Electrical characteristics of 4H-SiC BJTs at elevated temperatures2005In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 483-485, p. 897-900Article in journal (Refereed)
    Abstract [en]

    The DCI-V characteristics of 4H-SiC BJTs have been studied in the temperature range 25 ° C to 300 ° C. The DC current gain at 300 ° C decreased 56% compared to its value at 25 ° C. Under high power operation, the SiC BJTs were strongly influenced by self-heating, which significantly limits the performance of device. Pulsed measurements were performed and compared to DC measurements to distinguish the effects of self-heating. From DC IN measurements, the junction temperature and thermal resistance were extracted to 102 ° C and 19 ° C/W respectively for a power level of 7.3 W at ambient temperature 25 ° C.

  • 357.
    Lee, Hyung-Seok
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Domeij, Martin
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Ghandi, Reza
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Zetterling, Carl-Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    High-Current-Gain SiC BJTs With Regrown Extrinsic Base and Etched JTE2008In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 55, no 8, p. 1894-1898Article in journal (Refereed)
    Abstract [en]

    This paper describes successful fabrication of 4H-SiC bipolar junction transistors (BJTs) with a regrown extrinsic base layer and an etched junction termination extension (JTE). Large-area 4H-SiC BJTs measuring 1.8 x 1.8 nun (with an active area of 3.24 mm') showed a common emitter current gain 0 of 42, specific on-resistance Rsp ON of 9 mQ - em', and open-base breakdown voltage BVcEO of-1.75 kV at room temperature. The key to successful fabrication of high-current-gain SiC BJTs with a regrown extrinsic base is efficient removal of the p+ regrown layer from the surface of the emitter-base junction. The BJT with p+ regrown layer has the advantage of lower base contact resistivity and current gain that is less sensitive to the distance between the emitter edge and the base contact, compared to a BJT with ion-implanted base. Fabrication of BJTs without ion implantation means less lifetime-reducing defects, and in addition, the surface morphology is improved since high-temperature annealing becomes unnecessary. BJTs with flat-surface junction termination that combine etched regrown layers show about 250 V higher breakdown voltage than BJTs; with only etched flat-surface JTE.

  • 358.
    Lee, Hyung-Seok
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Domeij, Martin
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Zetterling, Carl-Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Low-forward-voltage-drop 4H-SiC BJTs without base contact implantation2008In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 55, no 8, p. 1907-1911Article in journal (Refereed)
    Abstract [en]

    Bipolar junction transistors (BJTs) of 4H-SiC, with a low collector--emitter forward voltage drop YCE, have been fabricated without base contact implantation. A comparison of BJTs on the same wafer with and without base contact implantation shows less than 10% higher VcE for the BJTs without base contact implantation. Omitting the base contact implantation eliminates high concentrations of implantation-induced defects that act as recombination centers. This is advantageous because it allows a shorter distance Wp+ between the emitter edge and the base contact, without affecting the current gain when no base contact implantation is used. The BJTs without contact implantation show a constant current gain as Wp+ was reduced from 3 to I pm, whereas the gain decreased by 45% for the BJTs with base contact implantation for the same reduction of Wp+. A key to the successful fabrication of low-forward-voltage-drop SiC BJTs without base contact implantation is the formation of low-resistivity Ni/Ti/Al ohmic contacts to the base. The contact resistivity on the base region (N-A approximate to 4 x 10(17) cm(-3)) was measured with linear transmission line method structures to PC = 1.9 X 10(-3) Omega cm(2), whereas the contact resistivity with the base contact implantation was PC = 1.3 x 10-4 Omega cm(2), both after rapid thermal processing annealing at 800 degrees C.

  • 359.
    Lee, Hyung-Seok
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Domeij, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Zetterling, Carl-Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lu, J
    Investigation of TiW contacts to 4H-SiC bipolar junction devices2006In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 527-529, p. 887-890Article in journal (Refereed)
    Abstract [en]

    One important challenge in SiC Bipolar Junction Transistor (BJT) fabrication is to form good ohmic contacts to both n-type and p-type SiC. In this paper, we have examined contact study in a SiC BJT process with sputter deposition of titanium tungsten contacts to both n-type and p-type regions followed by annealing at different temperatures between 750 T and 950 T. The contacts were characterized using linear transmission line method (LTLM) structures. To see the formation of compound phases, X-ray Diffraction (XRD) theta-2 theta scans were performed before and after annealing. The results indicate that 5 minutes annealing at 950 T of the n(+) contact is sufficient whereas the p(+) contacts remain non-ohmic after 30 minutes annealing. The n(+) emitter structure contact resistivity after 5 min annealing with 750 degrees C and 950 degrees C was 1.08 x 10(-3) Omega cm(2) and 4.08 x 10(-4) Omega cm(2), respectively. Small amorphous regions of silicon and carbon as well as titanium tungsten carbide regions were observed by high-resolution transmission electron microscopy (HRTEM), whereas less carbide formation and no amorphous regions were found in a sample with unsuccessful formation of TiW ohmic contacts.

  • 360.
    Leufvén, Ulrika
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Synchronization in a Wireless World: Can SyncML handle the task?2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increasing number of devices being used and the growing number of people that update the same information are driving the need for synchronization. There are a number of factors that contribute to the complexity of synchronization, these include networking technologies, communication protocols, mark up languages, data formats, etc. Until now there have been a number of vendors who have provided rather limited synchronization solutions, these have all been proprietary synchronization solutions which have not been interoperable or widely adopted. Today most synchronization solutions are hard to use, they often require installation of additional software and involve complex configuration setup.

    The SyncML Initiative is a relatively new industry initiative that has designed and developed a single, common data synchronization protocol that can be used industry-wide. Driving the initiative are Ericsson, IBM, Lotus, Motorola, Nokia, Palm Inc., Psion, and Starfish Software. SyncML is designed especially with the wireless world’s tight bandwidth and storage requirements in mind. The SyncML Initiative claims that "SyncML is the optimal choice for mobile synchronization."

    Today Microsoft is not a supporter of the SyncML Initiative. As Microsoft is a very involved in the world of data communication via software on personal computers and back end servers, and now software for handheld devices and mobile terminals, it was of great importance that Microsoft gain an insight into present and emerging standards and technologies in the wireless space. This report gives an overview of SyncML in the market place as well as a technical overview of the various elements of the SyncML protocol. It contains an analysis of SyncML based on these factors in order to establish if SyncML will succeed in achieving its goals. The report concludes with some recommendations based on the outcome of my analysis.

  • 361. Lewen, R.
    et al.
    Westergren, Urban
    KTH, Superseded Departments, Electronics. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Berglind, Eilert
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Design of inductive p-i-n diode matching for optical receivers with increased bit-rate operation2001In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 19, no 12, p. 1956-1963Article in journal (Refereed)
    Abstract [en]

    We have studied matching of a p-i-n photodiode (PD) with a single serial inductive element for broadband operation. The bit rate and rise time may be significantly improved, compared to a device without inductor for nonreturn-to-zero (NRZ) modulation. The matched device offers improved pulse equalization leading to increased receiver sensitivity, and reduces the need for an additional pulse-equalizing filter. The material is presented so that it can serve as a guideline of how the inductor can be included when choosing the thickness of the absorption layer and/or area for a p-i-n PD design, and ends with typical design examples.

  • 362. Li, F.
    et al.
    Badel, X.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wasserman, G.
    Whittenburg, S. L.
    Spinu, L.
    Wiley, J. B.
    Fabrication and assembly behavior of square microcapsules2006In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 18, no 3, p. 270-+Article in journal (Refereed)
    Abstract [en]

    Square microcapsules have been fabricated within porous silicon membranes. The capsules float in water when released from the membrane (see Figure). Dry capsules float with one of their edges pointing down, but after uptake of water, they float face down; the edge-down capsules assemble end-to-end while the face-down capsules assemble face-to-face.

  • 363. Li, F.
    et al.
    Badel, X.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wiley, J. B.
    Fabrication of colloidal crystals with tubular-like packings2005In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 127, no 10, p. 3268-3269Article in journal (Refereed)
  • 364. Li, F.
    et al.
    Badel, Xavier
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wiley, J. B.
    Colloidal crystal wires from directed assembly2005In: Micro- and Nanosystems-Materials and Devices, Materials Research Society, 2005, p. 477-482Conference paper (Refereed)
    Abstract [en]

    Colloidal crystal wires with tubular-like packings are prepared by the directed assembly of spheres into cylindrical one-dimensional channels. Silica spheres are infiltrated into porous silicon membranes, treated with silane, and annealed. Single annealing cycles are found to result in colloidal crystal wires with varied packing geometries, while repeated annealing produces a thin translucent silica sheath around the wires. Packing in the wires varies with the relative channel diameter of the silicon membrane where typical wires contain 4 to 7 helical strands. Both chiral and achiral packing geometries are observed. The fabrication of these wires is discussed and the relationship between channel size and packing structure detailed.

  • 365. Li, Z.
    et al.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ma, M.
    ECG signal generator design based on DFG model2006In: 2006 8th International Conference on Signal Processing: Volume 4, IEEE , 2006, p. 3245-3248Conference paper (Refereed)
    Abstract [en]

    ECG signals model described by data flow graph (DFG) is addressed in this paper. The model is built on the time processing. The principle of DFG modeling method for ECG signal is based on the idea of ECG time interval. According to the data processing flow, the each wave could be considered as a piece of ECG signal and the pieces could be processed in time sequence. According to the model, the time characters and parameters could be processed by the algorithm. The model is also useful for the design of ECG signal generator.

  • 366. Li, Z.
    et al.
    Liu, J.
    Lv, C.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Data compression and life signal acquisition SoC design2008Conference paper (Refereed)
    Abstract [en]

    A simple data compression method used for designing of SoC architecture of life signal acquisition is proposed in this paper. The health service is an important part of home network following the development of information technology. Considering the parameters of each life signal for information analysis the re-sampling method can be used as a compression method. Re-sampling method is not complex and can be implemented with simple circuit. The SoC is used for a health service system in the home network. The advantage of the method is of a SoC with low power consumption.

  • 367. Li, Z.
    et al.
    Liu, J.
    Wang, S.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    SoC model analysis for ECG data acquisition with wireless sensor network2009In: 3rd International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2009, 2009, p. 1276-1279Conference paper (Refereed)
    Abstract [en]

    Mixed signal SoC for ECG waveform acquisition is designed and discussed in this paper. The SoC is a terminal of a special wireless sensor network (WSN) as a data source. Time parameters and communication band width are discussed. Especially, to satisfy the requirements of ECG waveform data acquisition and transmission the relation of sampling rate and communication band width is discussed. Based on the analysis of ECG frequency characteristics and the real time requirements of the WSN, synchronous data acquisition and transmission architecture of the SoC is designed. The DFG (Data flow graphic) model of the architecture is built for time parameters analysis and circuits design as well.

  • 368. Li, Z.
    et al.
    Luo, L.
    Li, Shou
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Design for mixed-signal SoC with IPv4 for embedded instruments2007In: 2007 8th International Conference on Electronic Measurement and Instruments, ICEMI, IEEE , 2007, p. 269-273Conference paper (Refereed)
    Abstract [en]

    A SoC architecture used for with 8-bit CPU and IPv4 hardware is designed in this paper. The SoC is designed for embedded instrument. In additional, to according with the information transmission requirement of smart control system, the function of IPv4 is simplified to reduce the hardware. A function model used for model checking is also given. The function model is very simple and easy to be used in practice because we only take care about the transceiver function of IPv4 hardware.

  • 369. Li, Z.
    et al.
    Lv, C.
    Liu, J.
    Lu, M.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    SoC architecture with a switch bridge for wireless ECG data acquisition2009In: 2009 1st International Conference on Information Science and Engineering, ICISE 2009, 2009, p. 3701-3704Conference paper (Refereed)
    Abstract [en]

    NoC architecture with a switch bridge is designed for mixed signal SoC of the ETB (ECG T on body) applied in home healthcare wireless network. The SoC including multi CPU systems can be divided into different parts with data process function. Therefore each part of the system can work independently without influence each other. With the discussion of the performances of ETB, the switch bridge is a suitable NoC (network on chip) technology for reducing the dies size and power consumption. The switch bridge designed in this paper connects two CPU systems and two others digital circuitry components together. To the CPU systems, common digital circuitry is a part of the CPU system with the bridge. The architecture and logic function of the switch bridge is analyzed in detail and simulated. The simulation results demonstrate that the connection bridge can not only supply the connection of two CPU and two common modules, include display module and RAM, but also increased the running speed and system performance.

  • 370. Li, Z.
    et al.
    Xiu, L.
    Liu, J.
    Lv, C.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Error analysis of integrated resistor attenuation network2010In: Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010, 2010, p. 3714-3717Conference paper (Refereed)
    Abstract [en]

    The model and synthesis method of integrated linear attenuation network (LAC) used in mixed signal SoC for digital instrument are addressed in this paper. The model and synthesis method of the LAC used for electronics instrument is related with the application and implementation method. To the signal generator used in some electronics instrument, the LAC architecture could be linear and synthesized by resistor network and some additional circuits. Therefore, the spectrum properties of the LAC are relayed on the spectrum properties of additional circuits. The synthesis method is derived the formula of the LAC model. With the model, the integrated resistor network in the LAC used for measurement circuit module could be reduced. The LAC architecture synthesis method is suitable for the application of implementing a LAC with integrated circuit technology.

  • 371. Li, Zheying
    et al.
    Jia, L.
    Li, Shou
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    NoC design with DFG model for DSPS2010In: Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010, 2010, p. 3917-3920Conference paper (Refereed)
    Abstract [en]

    The mapping design of network on chip (NoC) is one of the cores of SoC design for digital signal process system (DSPS). A NoC mapping method based on data flow graph (DFG) is addressed in this paper. For modules of heterogeneous processors, central memory, and IPs (intellectual properties), DFG model analysis shows that DFG model provides important data transmission properties included the direction and contents of data transmitting, requirements of synchronization and speed of data transmission. The DFG model, therefore, can be the base of route mapping design for the NoC. In addition, node architecture of simple router used in generic regulable NoC (GRNoC) is also proposed in this paper. The simple router can increases the properties of data transmission in NoC and is more suitable for mapping design with DFG model.

  • 372. Lindberg, H.
    et al.
    Larsson, A.
    Strassner, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. Centre National de la Recherche Scientifique, France .
    A high power, single frequency, 1550 nm, semiconductor disk laser2005In: Conference on Lasers and Electro-Optics Europe - Technical Digest, 2005Conference paper (Refereed)
  • 373. Lindberg, H
    et al.
    Larsson, A
    Strassner, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Single-frequency operation of a high-power, long-wavelength semiconductor disk laser2005In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 30, no 17, p. 2260-2262Article in journal (Refereed)
    Abstract [en]

    An optically pumped, high-power, single-frequency semiconductor disk laser is demonstrated. A thin (50 mu m) diamond bonded to an InGaAsP gain chip provides the combined functions of heat removal and spectral filtering, thus eliminating the need for the additional intracavity etalons that are usually employed for single-frequency operation. In a short cavity (4 mm) configuration we obtained a maximum output power of 470 mW at 0 degrees C and 170 mW at 20 degrees C in a near-diffraction-limited beam (M-2 < 1.2). The emission wavelength was 1549 nm and the linewidth was less than 200 MHz.

  • 374. Lindberg, H.
    et al.
    Strassner, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Gerster, E.
    Bengtsson, J.
    Larsson, A.
    Thermal management of optically pumped long-wavelength InP-based semiconductor disk lasers2005In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 11, no 5, p. 1126-1134Article in journal (Refereed)
    Abstract [en]

    We have developed a numerical model for investigating material heating and its effects on the performance of optically pumped InP-based long-wavelength semiconductor disk lasers. Material heating and optical wavefront distortion due to thermal lensing are analyzed, and different approaches to reduce the intrinsic material heating are investigated numerically and experimentally. The results obtained indicate that material heating is significant in such lasers due to the poor thermal properties of the InP-based epitaxial layers of the gain chip. Substrate removal is shown to be an insufficient method to reduce the material heating; instead, crystalline heat spreaders bonded to the gain chip surface provide a convenient way to reduce the thermal impedance. Important parameters for such heat spreaders are a high thermal conductivity and a low thermooptic coefficient (dn / dT). With the use of a synthetic diamond heat spreader, a maximum pump limited output power of 780 mW in a near diffraction limited beam (M-2 < 1.2) was demonstrated at - 33 degrees C and 100 mW at room temperature.

  • 375. Lindberg, H
    et al.
    Strassner, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Larsson, A
    Improved spectral properties of an optically pumped semiconductor disk laser using a thin diamond heat spreader as an intracavity filter2005In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 17, no 7, p. 1363-1365Article in journal (Refereed)
    Abstract [en]

    This letter describes an optically pumped high-power InP-based semiconductor disk laser with a thin (50 mu m) diamond heat spreader bonded to the surface of the gain chip. The diamond heat spreader performs the multiple functions of heat removal, spectral filtering, and wavelength stabilization by utilizing the high thermal conductivity and the low thermooptic coefficient of diamond, along with the large free-spectral range of a thin intracavity etalon. A pump-power-limited output power of 680 mW at 1.55 mu m is demonstrated at a heat sink temperature of -30 degrees C, and 140 mW at room temperature. The spectral width was measured to be less than 0.08 nm and the spectral drift with temperature and pump power as low as 0.03 nm/degrees C and 0.14 nm/W, respectively.

  • 376. Lindfors, K.
    et al.
    Setälä, T.
    Kaivola, M.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Degree of polarization in focused light2005In: Frontiers in optics 2005/Laser science XXI: the 89th OSA annual meeting ; technical digest ; Hilton, Tucson El Conquistador, Golf & Tennis Resort, Tucson, Arizona, USA, technical conference: October 16 - 20, 2005, exhibit: October 18 - 19, 2005, Optical Society of America, 2005Conference paper (Refereed)
    Abstract [en]

    The degree of polarization in high-NA focused random optical fields is analyzed using the Richards-Wolf method and 3D spectral coherence theory. Significant changes in the polarization degree are predicted. These results are explained by considering the focal-field spectral densities and electric-field correlations.

  • 377.
    Lindgren, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Using GPRS and the Ronja Platform for Wireless Monitoring of Vehicles2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The evolution in the cellular and mobile data communication systems proceeds at a tremendous pace. More and more communication techniques are based on packet-switched technology instead of the circuit-switched ones. At the same time as these technologies become available to the market new kind of services are evolving, e.g. wireless monitoring of vehicles.

    Services like wireless monitoring of vehicles have been available on the market for more than a decade. Especially in Europe they are built upon circuit-switched technologies or message services with low transmission rates. Though with the upcoming packet-switched technologies the customers and service providers will get access to new types of capabilities regarding quality of service, billing, and transmission rates. To build these services new types of high availability service platforms are needed. There will be a strong requirement for scalability, fault tolerance, redundancy, and distribution. Additionally there’ll be a demand that the platform support hot upgrades, i.e. dynamic software upgrade during execution. These requirements are very common in telecommunications environments.

    In the report different wireless communication technologies are evaluated and the General Packet Radio Service (GPRS) is chosen as the means of communication. The reason is that it is a packet-switched technology, the transmission rate is rather high, it supports Internet Protocol (IP) data, and it’s the first step in the evolution path towards the third generation (3G) wireless communication systems. Services based on GPRS can also be used in the future 3G networks without modifications.

    Different high availability platforms were also evaluated regarding the requirements placed on future service platforms. The conclusion is that more and more of these platforms will move from a hardware centric approach to a more software-based architecture. Of the platforms evaluated, the conclusion is that Ronja is the platform most suited for the task.

    Future services, e.g. wireless monitoring of vehicles, can benefit from using Ronja and GPRS. The time and money saved by using the high availability functionality provided by the Ronja platform are significant. To use GPRS as the communication media may also reduce the costs for the customers that use these kinds of services.

  • 378. Lindgren, S.
    et al.
    Ahlfeldt, H.
    Backlin, L.
    Forssen, L.
    Vieider, C.
    Elderstig, H.
    Svensson, M.
    Granlund, L.
    Kerzar, B.
    Broberg, B.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Forzelius, E.
    Nilsson, S.
    Laser flip-chip mounting for passive alignment and high-frequency modulation1996In: Optical Communication, 1996. ECOC ’96. 22nd European Conference on, 1996, Vol. 1, p. 103-106Conference paper (Refereed)
    Abstract [en]

    We have developed a silicon motherboard for flip-chip mounting of lasers in a way that is compatible with high-frequency modulation (24 GHz) and which allows passive alignment of the lasers to single-mode fibres.

  • 379.
    Lindgren, Stefan
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Åhlfeldt, Henrik
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Bäcklin, Lennart
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Forssén, Lili
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Vieider, Christian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Elderstig, Håkan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Svensson, Magnus
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Granlund, Lennart
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Andersson, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kerzar, Boris
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Broberg, Björn
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Forzelius, Elisabeth
    KTH, Superseded Departments, Electronics.
    Nilsson, Stefan
    KTH, Superseded Departments, Electronics.
    24-GHz modulation bandwidth and passive alignment of flip-chip mounted DFB laser diodes1997In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 9, no 3, p. 306-308Article in journal (Refereed)
  • 380.
    Linnarsson, Margareta
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Janson, Martin S.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Forsberg, U.
    Janzen, E.
    In-diffusion, trapping and out-diffusion of deuterium in 4H-SiC substrates2006In: Silicon Carbide and Related Materials 2005, Pts 1 and 2 / [ed] Devaty, RP, 2006, Vol. 527-529, p. 637-640Conference paper (Refereed)
    Abstract [en]

    Incorporation of hydrogen/deuterium in n-, p-type, and semi-insulating 4H-SiC substrates during epitaxial growth at 1590 degrees C has been studied in detail by secondary ion mass spectrometry. Out-diffusion has been investigated in samples subsequently annealed at high temperatures. After the epitaxial growth, deuterium is detected throughout the entire substrates. Out-diffusion can be observed after anneals at 1300 degrees C, but traces of deuterium can still be found in samples annealed as high as 1700 degrees C. A trap limited diffusion mechanism is proposed with vacancy related hydrogen trapping centers in n-type and semi insulating 4H-SiC substrates.

  • 381.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Janson, Martin S.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nordell, Nils
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Wong-Leung, J.
    Schoner, A.
    Formation of precipitates in heavily boron doped 4H-SiC2006In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 252, no 15, p. 5316-5320Article in journal (Refereed)
    Abstract [en]

    Secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) are utilized to study precipitation and the solubility of B in 4H-SiC epitaxial layers super saturated with B. Heat treatments are performed in Ar atmosphere in an rf-heated furnace at temperatures between 1700 and 2000 degrees C. SIMS ion images, and TEM micrographs reveal the formation of two types of precipitates where the larger, more thermally stable one is suggested to be B4C. The boron solubility is determined from SIMS depth profiles and is shown to follow the Arrhenius expression: 7.1 x 10(22) exp(-1.4 eV/k(B)T) cm(-3) over the studied temperature range.

  • 382.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Optoelectronics - Nanocrystals brighten transistors2005In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 4, no 2, p. 117-119Article in journal (Refereed)
    Abstract [en]

    Silicon nanocrystals provide efficient means of generating light that is both tunable and compatible with conventional microelectronics. However, progress has been hampered by difficulties in achieving efficient carrier injection. A new approach could provide the solution.

  • 383.
    Linnros, Jan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Badel, Xavier
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Kleimann, Pascal
    Macro pore and pillar array formation in silicon by electrochemical etching2006In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T126, p. 72-76Article in journal (Refereed)
    Abstract [en]

    Electrochemical etching may be used to form high aspect-ratio pores and pillars in silicon. Starting from lithographically patterned surfaces, regular arrays of macro pores or pillars can be fabricated. The pitch and pillar) pore size must then scale with the depletion width, in turn set by the material resistivity. We review various results where the achievable pore diameter ranges from 100 mu m for high resistivity material to the submicron range for highly doped wafers. At slightly higher current density and using different patterns, pillars or walls may be formed. The fabricated structures may be further processed and we demonstrate oxidation, uniform wall doping and finally, filling of the structures to result in functional materials. Applications include both optical, microelectronic, material and bio-applications.

  • 384. Litnovsky, A.
    et al.
    De Temmerman, G.
    Wienhold, P.
    Philipps, V.
    Schmitz, O.
    Samm, U.
    Sergienko, G.
    Oelhafen, P.
    Rubel, Marek
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics. KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Emmoth, Birger
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Direct comparative test of single crystal and polycrystalline diagnostic mirrors exposed in TEXTOR in erosion conditions2005In: 32nd EPS Conference on Plasma Physics 2005, EPS 2005, Held with the 8th International Workshop on Fast Ignition of Fusion Targets: Europhysics Conference Abstracts, 2005, p. 1726-1729Conference paper (Refereed)
    Abstract [en]

    First direct comparative test of single crystal and polycrystalline diagnostic mirror materials under erosion conditions has been made in TEXTOR. Before exposure in TEXTOR, glow discharge cleaning has efficiently restored the reflectivity of initially oxidized mirrors. After the exposure, no significant changes in total reflectivity were observed. Drastic increase of diffuse reflectivity was measured for polycrystalline molybdenum mirror, but not for the single crystal. Thus, specular reflectivity of single crystal is significantly higher than of polycrystalline one. The most affected wavelength range is 250-1000 nm, no significant changes of reflectivity was noticed in the range 1000-2000 nm. No or negligible effect of erosion on polarization characteristics of mirrors was measured.

  • 385. Litnovsky, A.
    et al.
    Philipps, V.
    Wienhold, P.
    Sergienko, G.
    Emmoth, Birger
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rubel, Marek J.
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Breuer, U.
    Wessel, E.
    Experimental investigations of castellated monoblock structures in TEXTOR2005In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 337-39, no 1-3, p. 917-921Article in journal (Refereed)
    Abstract [en]

    To insure the thermo-mechanical durability of ITER it is planned to manufacture the castellated armour of the divertor i.e. to split the armour into cells [W. Daener et al., Fusion Eng. Des. 61T62 (2002) 61]. This will cause an increase of the surface area and may lead to carbon deposition and tritium accumulation in the gaps in between cells. To investigate the processes of deposition and fuel accumulation in gaps, a castellated test-limiter was exposed to the SOL plasma of TEXTOR. The geometry of castellation used was the same as proposed for the vertical divertor target in ITER [W. Daener et al., Fusion Eng. Des. 61T62 (2002) 61]. After exposure the limiter was investigated with various surface diagnostic techniques. Deposited layers containing carbon, hydrogen, deuterium and boron were found both on top plasma-facing surfaces and in the gaps. The amount of deuterium in the gaps was at least 30% of that found on the top surfaces.

  • 386.
    Liu, Bo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    The Integration of GSM and WLAN Systems Based on a Mobile Terminal2002Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless and Internet technologies are major driving forces in telecommunication today, which both have brought great changes to human life. The evolution of Personal Communication Systems (PCS) was expected to provide a mobile user with voice, data, and multi-media anytime & anywhere. During the past decades, GSM systems have been increasingly deployed worldwide, and GPRS and 3G as the successors of GSM have started to be delivered in some places, but with much lower speed than expected by the venders of communication systems and to the disappointment of investors. Fortunately, another wireless network – Wireless Local Area Networks (WLAN) are widespread in schools, shopping centers, hotels, and airports etc., so called hotspots. In contrast, with respect to bandwidth and coverage area, GSM, GPRS, UMTS are low speed Wireless Wide Area Networks (WWANs).

    WLAN was expected to provide high-speed data, but within limited coverage area, while GSM provides voice service at anytime & anywhere, and GPRS provides low speed data anytime & anywhere. Hence, the integration of WLAN and GSM/GPRS is a very promising technology, which is an innovative method to improve the overall system efficiency and optimize the scarce resource of GSM/GPRS capacity. The aim of this Master’s Thesis is to study the integration of GSM/WLAN from different perspectives, including both business and technology. Because GSM had been deployed in most of world and WLAN hotspots are increasingly common, the study is very significant in practice today and in the near future. Based on the investigation and study, a prototype system was built, some implementation issues were investigated, and problems of further commercialization were examined.

  • 387. Liu, C. P.
    et al.
    Chuang, C. H.
    Karlsson, S.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yu, Y.
    Tsegaye, T.
    Krysa, A. B.
    Roberts, J. S.
    Seeds, A. J.
    High-speed 1.56 µm asymmetric Fabry-Perot modulator/detector (AFPMD) for radio-over-fibre applications2005In: Optical Communication, 2005. ECOC 2005. 31st European Conference on, 2005, Vol. 3, p. 597-598Conference paper (Refereed)
    Abstract [en]

    We have fabricated modulator/detectors with modulation bandwidths exceeding 15 GHz, the highest yet reported for InGaAsP/InGaAsP MQW AFPMDs. Wavelength dependence of the modulated output power at microwave frequencies is reported for the first time.

  • 388. Liu, C. P.
    et al.
    Chuang, C. H.
    Karlsson, Sven
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yu, Y.
    Tsegaye, T.
    Krysa, A. B.
    Roberts, J. S.
    Seeds, A. J.
    High-Speed 1.56-μm Multiple Quantum Well Asymmetric Fabry-Perot Modulator/Detector (AFPMD) for Radio-Over-Fibre Applications2005In: Microwave Photonics, 2005. MWP 2005. International Topical Meeting on, IEEE , 2005, p. 137-140Conference paper (Refereed)
    Abstract [en]

    We have designed and fabricated air-bridged optical modulator/detectors with modulation bandwidth exceeding 15GHz, the highest yet reported for InGaAsP/InGaAsP MQW AFPMDs. Wavelength dependence of the modulated output power at microwave frequencies is reported for the first time and the wide optical bandwidths ( gt; 17nm) so measured suggest that the AFPMD can be used with low-cost uncooled CWDM lasers in radio-over-fibre applications.

  • 389.
    Liu, George Y.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Maguire Jr., Gerald Q.
    KTH, Superseded Departments, Teleinformatics.
    A survey of caching and prefetching techniques in distributed systems1994Report (Other academic)
  • 390. Liu, J.
    et al.
    Lv, C.
    Li, Z.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Switch bridge architecture of NoC for wireless ECG data acquisition2009In: 3rd International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2009, 2009, p. 887-890Conference paper (Refereed)
    Abstract [en]

    A switch bridge is addressed for the interconnection of two CPU systems in the SoC of the ETB (ECG terminal on body) in home healthcare wireless network. The SoC including multi CPU systems can be divided into different parts with data process function. Therefore each part of the system can work independently without influence each other. With the discussion of the performances of HAB and home networking, the switch bridge is a suitable technology for reducing the dies size and power consumption. The switch bridge designed in this paper connects two CPU systems and two others digital circuitry components together. To the CPU systems, common digital circuitry is a part of the CPU system with the bridge. The architecture and logic function of the switch bridge is analyzed in detail and simulated. The simulation results demonstrate that the connection bridge can not only supply the connection of two CPU and two common components, include display module and RAM, but also increased the running speed and system performance.

  • 391.
    Liu, Jian
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Weerasekera, Roshan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Zheng, Li-Rong
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tenhunen, Hannu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nano scale autonomous error-tolerant (AET) cellular network2005In: 2005 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2005 Technical Proceedings, 2005, p. 748-752Conference paper (Refereed)
    Abstract [en]

    In this paper, the nano-CMOS hybrid Autonomous Error-Tolerant (AET) cellular network architecture, which integrates today's mature CMOS technology with emerging nanotechnology, is proposed. Within the cellular network, each AET cell contains a nanocore, CMOS cell peripherals and their interface circuits. The overall network is homogenous. These imply strict constraints for intercellular connection schemes and routing policies. Depending on the communication requirement between two nodes, different routing methods apply.

  • 392.
    Liu, Jian
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Weerasekera, Roshan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Zheng, Li-Rong
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tenhunen, Hannu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nanocore/CMOS hybrid system-on-package (SoP) architecture for autonomous error-tolerant (AET) cellular array network2005In: 2005 5th IEEE Conference on Nanotechnology, 2005, p. 353-356Conference paper (Refereed)
    Abstract [en]

    In this paper, the nanocore/CMOS hybrid system-on-package (SoP) autonomous error-tolerant (AET) cellular network architecture, which integrates today’s mature CMOS technology with emerging nanotechnology, is proposed. Within the cellular network, each AET cell contains a nanocore, CMOS cell peripherals and their interface circuits in a silicon platform. The overall network is homogeneous. These imply strict constraints for intercellular connection schemes and routing policies. Depending on the communication requirement between two nodes.

  • 393.
    Liu, Liu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Design, Fabrication, and Characterization of Nano-Photonic Components Based on Silicon and Plasmonic Material2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Size reduction is a key issue in the development of contemporary integrated photonics. This thesis is mainly devoted to study some integrated photonic components in sub-wavelength or nanometric scales, both theoretically and experimentally. The possible approaches to reduce the sizes or to increase the functionalities of photonic components are discussed, including waveguides and devices based on silicon nanowires, photonic crystals, surface plasmons, and some near-field plasmonic components.

    First, some numerical methods, including the finite-difference time-domain method and the full-vectorial finite-difference mode solver, are introduced. The finite-difference time-domain method can be used to investigate the interaction of light fields with virtually arbitrary structures. The full-vectorial finite-difference mode solver is mainly used for calculating the eigenmodes of a waveguide structure.

    The fabrication and characterization technologies for nano-photonic components are reviewed. The fabrications are mainly based on semiconductor cleanroom facilities, which include thin film deposition, electron beam lithography, and etching. The characterization setups with the end-fire coupling and the vertical grating coupling are also described.

    Silicon nanowire waveguides and related devices are studied. Arrayed waveguide gratings with 11nm and 1.6nm channel spacing are fabricated and characterized. The dimension of these arrayed waveguide gratings is around 100 μm, which is 1--2 order of magnitude smaller than conventional silica based arrayed waveguide gratings. A compact polarization beam splitter employing positive/negative refraction based on a photonic crystal of silicon pillars is designed and demonstrated. Extinction ratio of ~15dB is achieved experimentally in a wide wavelength range.

    Surface plasmon waveguides and devices are analyzed theoretically. With surface plasmons the light field can be confined in a sub-wavelength dimension. Some related photonic devices, e.g., directional couplers and ring resonators, are studied. We also show that some ideas and principles of microwave devices, e.g., a branch-line coupler, can be borrowed for building corresponding surface plasmon based devices. Near-field plasmonic components, including near-field scanning optical microscope probes and left handed material slab lenses, are also analyzed. Some novel designs are introduced to enhance the corresponding systems.

  • 394.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ao, Xianyu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Compact polarization beam splitter employing positive/negative refraction based on photonic crystals of pillar type2006In: Optoeletronic Materials and Devices, Pts 1 and 2 / [ed] Lee, YH; Koyama, F; Luo, Y, BELLINGHAM, WA: SPIE-INT SOC OPTICAL ENGINEERING , 2006, p. U74-U81Conference paper (Refereed)
    Abstract [en]

    A polarization beam splitter based on a two-dimensional photonic crystal slab is presented. In the designed photonic crystal, the TE polarization is negatively refracted, while the TM polarization is positively refracted. The photonic crystal is composed of silicon pillars in a triangular lattice. The whole device is very compact (20x20 mu m(2)), and is compatible with the planar integration. The measurement results show that the extinction ratio is similar to 15dB from 1530 to 1610nm.

  • 395.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Dai, Daoxin
    Dainese, Matteo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Compact Arrayed Waveguide Grating Demultiplexers Based on Amorphous Silicon Nanowires2006In: Integrated Photonics Research and Applications/Nanophotonics 2006, NWB5,April 24–28, 2006, Uncasville, Connecticut, USA., 2006Conference paper (Refereed)
    Abstract [en]

    A novel and flexible technology for ultra compact AWGs based on amorphous silicon nanowires is presented. A 4×4 AWG with a total dimension of 50×50µm was fabricated. 11nm channel spacing and -10dB crosstalk was obtained.

  • 396.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Han, Z.
    Forsberg, Erik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ultra-compact Directional Couplers and Mach-Zehnder Interferometers employing Surface Plasmon Polaritons2005In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 259, no 2, p. 690-695Article in journal (Refereed)
    Abstract [en]

    Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polaritons are proposed and their characteristics are analyzed numerically using a finite-difference time-domain method. It is shown that these devices can have transverse size smaller than the incident wavelength and can then be regarded as true subwavelength photonic elements. The ultra-compact characteristic of these devices can be utilized as a basis of next generation of integrated photonic circuits. Furthermore, calculations also show that these devices behave differently from their traditional all-dielectric counterparts. For the proposed optical directional coupler, the phase difference between the two output ports will no longer be 90 degrees even when the two ports have the same power outputs.

  • 397.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    Design of metal-cladded near-field fiber probes with a dispersive body-of-revolution finite-difference time-domain method2005In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 44, no 17, p. 3429-3437Article in journal (Refereed)
    Abstract [en]

     A dispersive body-of-revolution finite-difference time-domain method is developed to simulate metal-cladded near-field scanning optical microscope (NSOM) probes. Two types of NSOM probe (aperture and plasmon NSOM probes) are analyzed and designed with this fast method. The influence of the metal-cladding thickness and the excitation mode on the performance of the NSOM probes is studied. We introduce a new scheme of illumination-mode NSOM by employing the plasmon NSOM probe with the TM01 mode excitation. Such a NSOM probe is designed, and we demonstrate its advantages over the conventional aperture NSOM probe by scanning across a metallic object.

  • 398.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Electrical Engineering (EES).
    Novel surface plasmon waveguide for high integration2005In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 13, p. 6645-6650Article in journal (Refereed)
    Abstract [en]

    A novel surface plasmon waveguide structure is proposed for highly integrated planar lightwave circuits. By etching a small trench through a metallic thin film on a silica substrate, a guided mode with highly confined light fields is realized. The mode properties of the proposed structure are studied. The necessity of using a polymer upper-cladding is discussed. The coupling between two closely positioned waveguides and a 90° bending are also studied numerically. Sharp bending and high integration can be realized with the present surface plasmon waveguide. The proposed structure is easy to fabricate as compared with some other types of surface plasmon waveguides for high integration

  • 399.
    Liu, Liu
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Dai, Daoxin
    Han, Zhandhua
    Highly integrated planar lightwave circuits based on plasmonic and Si nano-waveguides2006In: Passive Components and Fiber-Based Devices III, Pts 1 and 2 / [ed] Lee, SB; Sun, Y; Qui, SC; Fleming, SC; White, IH, BELLINGHAM, WA: SPIE-INT SOC OPTICAL ENGINEERING , 2006, p. U765-U779Conference paper (Refereed)
    Abstract [en]

    Planar lightwave circuits (PLC) based on nanophotonic waveguides are becoming more and more attractive because of their ultrasmall sizes and possibility for realizing large scale monolithic integration with a very high integration density. In this paper we discuss two attractive types of nanophotonic waveguides based on dielectrics or metals. For the dielectric type, a silicon-on-insulator (SOI) strip waveguide is considered, and ultra-compact photonic integrated devices such as polarization-insensitive arrayed waveguide grating (de)multiplexers are obtained. Based on the fact that light can be confined tightly in a single interface between a metal and dielectric, a surface plasmon (SP) waveguide can offer a tight confinement for the light field. The cross-sectional size of an SP waveguide could be pushed down to tens of nanometers, i.e. beyond the diffraction limit. An accurate anaylysis for an SP waveguide formed by a dielectric nano-trench in a metal is presented. A novel subwavelength index-guided multimode plasmonic waveguide is introduced and an ultra-compact MMI power splitter is designed.

  • 400. Liu, X. Y.
    et al.
    Fälth, J. F.
    Andersson, T. G.
    Holmström, Petter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jänes, Peter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Structural and optical properties of GaN/AlN multiple quantum wells for intersubband applications2005In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 278, no 1-4, p. 397-401Article in journal (Refereed)
    Abstract [en]

    GaN/AIN multiple quantum well structures of 1, 5 and 20 periods were grown by molecular beam epitaxy (MBE). To investigate structural parameters, symmetrical scan (0002) and reciprocal space mapping in the vicinity of the GaN (10 15) plane were made by X-ray diffraction (XRD). The layer thickness, composition and relaxation were determined and gave good agreement with simulated results. The 20 period multiple quantum well (MQW) sample exhibited an intersubband resonance at 360 meV, which corresponds well to the structure data determined by XRD.

567891011 351 - 400 of 741
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