44,559 research outputs found

    Validation by Measurements of a IC Modeling Approach for SiP Applications

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    The growing importance of signal integrity (SI) analysis in integrated circuits (ICs), revealed by modern systemin-package methods, is demanding for new models for the IC sub-systems which are both accurate, efficient and extractable by simple measurement procedures. This paper presents the contribution for the establishment of an integrated IC modeling approach whose performance is assessed by direct comparison with the signals measured in laboratory of two distinct memory IC devices. Based on the identification of the main blocks of a typical IC device, the modeling approach consists of a network of system-level sub-models, some of which with already demonstrated accuracy, which simulated the IC interfacing behavior. Emphasis is given to the procedures that were developed to validate by means of laboratory measurements (and not by comparison with circuit-level simulations) the model performance, which is a novel and important aspect that should be considered in the design of IC models that are useful for SI analysi

    An Approach to Assess Solder Interconnect Degradation Using Digital Signal

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    Department of Human and Systems EngineeringDigital signals used in electronic systems require reliable data communication. It is necessary to monitor the system health continuously to prevent system failure in advance. Solder joints in electronic assemblies are one of the major failure sites under thermal, mechanical and chemical stress conditions during their operation. Solder joint degradation usually starts from the surface where high speed signals are concentrated due to the phenomenon referred to as the skin effect. Due to the skin effect, high speed signals are sensitive when detecting the early stages of solder joint degradation. The objective of the thesis is to assess solder joint degradation in a non-destructive way based on digital signal characterization. For accelerated life testing the stress conditions were designed in order to generate gradual degradation of solder joints. The signal generated by a digital signal transceiver was travelling through the solder joints to continuously monitor the signal integrity under the stress conditions. The signal properities were obtained by eye parameters and jitter, which represented the characteristics of the digital signal in terms of noise and timing error. The eye parameters and jitter exhibited significant increase after the exposure of the solder joints to the stress conditions. The test results indicated the deterioration of the signal integrity resulted from the solder joint degradation, and proved that high speed digital signals could serve as a non-destructive tool for sensing physical degradation. Since this approach is based on the digital signals used in electronic systems, it can be implemented without requiring additional sensing devices. Furthermore, this approach can serve as a proactive prognostic tool, which provides real-time health monitoring of electronic systems and triggers early warning for impending failure.ope

    Antenna Behaviour in the Presence of Human Body

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    Mobile phones are widely used nowadays. The demand in the new generations of mobile phones is better performance. Typically the mobile phone performance is derived assuming an ideal antenna impedance of 50Ω. Some work has been done in understanding the behaviour of the antenna impedance in a real environment [1], [2], [3]. This work continued the exploration of the difference between the ideal antenna impedance and the antenna impedance in a real environment. In particular the analysis was carried out measuring the antenna impedance in presence of the human body and relating it to the position of the hand and of the hand + head. Two types of antennas were considered: PIFA antennas and ceramic antennas. Several positions of the hand and of the hand + head were considered. These positions were selected after an accurate study about how people on the street normally handle their mobile phones. The study consisted of two steps: 1) observation of the typical positions of the hand and of the\ud hand + head with respect to the mobile phone; 2) their imitation in the lab for the measurements The outcome of the investigation was the changing of the impedance is primary due to a changing of its imaginary part. The real part is affected but not in dramatic way

    Implementation of packaged integrated antenna with embedded front end for Bluetooth applications

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    The design, integration and realization of system in enhanced package approach towards fully functional system level integration by using a compact Bluetooth USB dongle as the demonstrator is presented here. The integration was done on FR4 substrates, which is totally compatible with today’s printed circuit board manufacturing capability. A commercially available Bluetooth integrated chip was chosen as the chipset of our demonstrator, and a package integrated antenna together with an embedded front end completes the system in package integration. The front end developed here is based on an embedded meander line combline filter and an embedded transformer balun. The filter has a 35% area reduction when compared with the classical combline filter and similar performance. The balun has the coils distributed on three layers that minimized the board area needed it and optimizes the performances. The proposed packaged integrated antenna approach is successfully demonstrated here and the new module shows excellent performance when compared with a commercial solution, surpassing the normal Bluetooth class II dongle range which is up to 10 m and increasing the module range up to 120 m without an extra power amplifier

    Design of high gradient, high repetition rate damped C-band rf structures

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    The gamma beam system of the European Extreme Light Infrastructure–Nuclear Physics project foresees the use of a multibunch train colliding with a high intensity recirculated laser pulse. The linac energy booster is composed of 12 traveling wave C-band structures, 1.8 m long with a field phase advance per cell of 2π=3 and a repetition rate of 100 Hz. Because of the multibunch operation, the structures have been designed with a dipole higher order mode (HOM) damping system to avoid beam breakup (BBU). They are quasiconstant gradient structures with symmetric input couplers and a very effective damping of the HOMs in each cell based on silicon carbide (SiC) rf absorbers coupled to each cell through waveguides. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce the cost of the structures. In the paper, after a review of the beam dynamics issues related to the BBU effects, we discuss the electromagnetic and thermomechanic design criteria of the structures. We also illustrate the criteria to compensate the beam loading and the rf measurements that show the effectiveness of the HOM damping

    Communication system for a tooth-mounted RF sensor used for continuous monitoring of nutrient intake

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    In this Thesis, the communication system of a wearable device that monitors the user’s diet is studied. Based in a novel RF metamaterial-based mouth sensor, different decisions have to be made concerning the system’s technologies, such as the power source options for the device, the wireless technology used for communications and the method to obtain data from the sensor. These issues, along with other safety rules and regulations, are reviewed, as the first stage of development of the Food-Intake Monitoring projectOutgoin

    Ferrite cavities

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    Ferrite cavities are used in synchrotrons and storage rings if the maximum RF frequency is in the order of a few MHz. We present a simple model for describing ferrite cavities. The most important parameters are defined, and the material properties are discussed. Several practical aspects are summarized, and the GSI SIS18 ferrite cavity is presented as an example.Comment: 19 pages, contribution to the CAS - CERN Accelerator School: Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar

    Investigations on electromagnetic noises and interactions in electronic architectures : a tutorial case on a mobile system

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    Electromagnetic interactions become critic in embedded and smart electronic structures. The increase of electronic performances confined in a finite volume or support for mobile applications defines new electromagnetic environment and compatibility configurations (EMC). With canonical demonstrators developed for tutorials and EMC experiences, this paper present basic principles and experimental techniques to investigate and control these severe interferences. Some issues are reviewed to present actual and future scientific challenges for EMC at electronic circuit level

    Application and evaluation of the RF charge-pumping technique

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    In this paper, we will discuss the extendibility of the charge-pumping (CP) technique toward frequencies up to 4 GHz. Such high frequencies are attractive when a significant gate leakage current flows, obscuring the CP current at lower pumping frequencies.\ud It is shown that using RF gate excitation, accurate CP curves can be obtained on MOS devices with a leakage current density exceeding 1 A•cm−2 . A theoretical analysis of the trap response to RF gate voltage signals is presented, giving a clear insight on the benefits and limitations of the technique.\u

    Microwave Measurements Part I: Linear Measurements

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    An Overview of the most relevant issues concerning RF and microwave linear measurements is presented. Vector Network Analyzer foremost used instrumentation for this kind of measures is describe
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