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Dissertations / Theses on the topic 'RF measurements'

Author: Grafiati
Published: 4 June 2021
Last updated: 30 November 2024

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1

Al-Tahir, Hibah. "Multidimensional Measurements : on RF Power Amplifiers." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-729.

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In this thesis, a measurement system was set to perform comprehensive measurements on RF power amplifiers. Data obtained from the measurements is then processed mathematically to obtain three dimensional graphs of the basic parameters affected or generated by nonlinearities of the amplifier i.e. gain, efficiency and distortion. Using a class AB amplifier as the DUT, two sets of signals – both swept in power level and frequency - were generated to validate the method, a two-tone signal and a WCDMA signal. The three dimensional plot gives a thorough representation of the behavior of the amplifier in any arbitrary range of spectrum and input level. Sweet spots are consequently easy to detect and analyze. The measurement setup can also yield other three dimensional plots of variations of gain, efficiency or distortion versus frequencies and input levels. Moreover, the measurement tool can be used to plot traditional two dimensional plots such as, input versus gain, frequency versus efficiency etc, making the setup a practical tool for RF amplifiers designers.

The test signals were generated by computer then sent to a vector signal generator that generates the actual signals fed to the amplifier. The output of the amplifier is fed to a vector signal analyzer then collected by computer to be handled. MATLAB® was used throughout the entire process.

The distortion considered in the case of the two-tone signals is the third order intermodulation distortion (IM3) whereas Adjacent Channel Power Ratio (ACPR) was considered in the case of WCDMA.

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2

Condo, Neira Edith Graciela. "Multidimensional Measurements on RF Power Amplifiers." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-804.

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Measurements are important to specify and verify properties for components, modules and systems. The specifications for a certain figure of merit are usually given in a numerical value or a two dimensional plot. However, there are some devices, like power amplifiers with certain figure of merits that depends on two or more working conditions, requiring a three dimensional plot.

This thesis presents a measurement method including graphical user interface of three parameters gain, efficiency and distortion when two-tone or WCDMA signals are used as an input to the PA.

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3

Hellgesson, Markus, and Daniel Andersson. "Design of automatic measurements systems for characterizing RF-components." Thesis, University West, Department of Technology, Mathematics and Computer Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-387.

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4

Anderson, Colin Andrew. "Temporal Langmuir probe measurements in low frequency RF plasmas." Thesis, University of Ulster, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359715.

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5

Schwartz, Benjamin M. (Benjamin Matthew). "Mapping bulk electrical properties with non-contact RF measurements." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36118.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.
Includes bibliographical references (leaf 43).
The human body is composed primarily of dielectric tissue with spatially varying permittivity and conductivity. Traditional MRI does not measure these properties. Instead, the conductivity of the patient is a nuisance, causing unpredictable detuning of coils and field inhomogeneities. This thesis presents a method for mapping the electrodynamic properties of the patient's body with both MR and non-MR techniques. Such mapping has direct applications for medical imaging and SAR calculation.
by Benjamin M. Schwartz.
S.B.
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6

Gurbuz, Ozan Dogan. "Reliability Improvement Of Rf Mems Devices Based On Lifetime Measurements." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612320/index.pdf.

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This thesis presents fabrication of shunt, capacitive contact type RF MEMS switches which are designed according to given mm-wave performance specifications. The designed switches are modified for investigation in terms of reliability and lifetime. To observe the real-time performance of switches a time domain measurement setup is established and a CV (capacitance vs. voltage) curve measurement system is also included to measure CV curves, pull-in and hold-down voltages and the shifts of these due to actuations. By using the established setup reliability and lifetime measurements under different bias waveforms in different environments are performed. After investigation for the most suitable condition for improving lifetime long-term tests are performed and the outstanding result of more than 885 hours of operation under cycling bias waveform is obtained.
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7

Kim, Daeyoung. "Propagation measurements and system design for long-range RF tags." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13876.

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8

Krautschik, Christof Gabriel 1957. "Impedance determination of a RF plasma discharge by external measurements." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277141.

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The equivalent impedance of a RF plasma was experimentally determined by monitoring the voltage and current waveform for different input powers in real time. Average ion energies and fluxes were determined by a computer model which takes ion collisions in the sheath regions into account. In addition two models were proposed which explain how RF energy is converted to DC potential energy in the sheath. Etch rates of Si in a CF₄ discharge were also evaluated and related to the measurements.
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9

Kline, Loren A. "Microwave Interferometry Diagnostic Applications for Measurements of Explosives." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1783.

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Microwave interferometry (MI) is a Doppler based diagnostic tool used to measure the detonation velocity of explosives, which has applications to explosive safety. The geometry used in existing MI experiments is cylindrical explosives pellets layered in a cylindrical case. It is of interest to Lawrence Livermore National Labs to measure additional geometries that may be overmoded, meaning that the geometries propagate higher-order transverse electromagnetic waves. The goal of my project is to measure and analyze the input reflection from a novel structure and to find a good frequency to use in an experiment using this structure. Two methods of determining a good frequency are applied to the phase of the input reflection. The first method is R2, used to measure the linearity of input reflection phase. The second is a zero-crossing method that measures how periodic the input reflection phase is. Frequencies with R2 values higher than .995 may be usable for an experiment in the novel structure.
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10

Haapala, Linus, and Aleksander Eriksson. "RF High Power Amplifiers for FREIA – ESS : design, fabrication and measurements." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-263549.

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The FREIA laboratory is a Facility for REsearch Instrumentation and Acceleratior development at Uppsala University, Sweden, constructed recently to test and develop superconducting accelerating cavities and their high power RF sources. FREIA's activity target initially the European Spallation Source (ESS) requirements for testing spoke cavities and RF power stations, typically 400 kW per cavity. Different power stations will be installed at the FREIA laboratory. The first one is based on vacuum tubes and the second on a combination of solid state modules. In this context, we investigate different related aspects, such as power generation and power combination. For the characterization of solid state amplifier modules in pulsed mode, at ESS specifications, we implement a Hot Sparameter measurement set-up, allowing in addition the measurement of different parameters such as gain and efficiency. Two new solid state amplifier modules are designed, constructed and measured at 352 MHz, using commercially available LDMOS transistors. Preliminary results show a drain efficiency of 71 % at 1300 W pulsed output power. The effects of changing quiescent current (IDq) and drain voltage are investigated, aswell as the possibilities to combine several modules together.
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11

Hakim, Bandar M. "Precise SAR measurements in the near-field of RF antenna systems." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3532.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.
Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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12

Roth, Weston Charles 1970. "Electrical characterization and plasma impedance measurements of a RF plasma etch system." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/291351.

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A modified Tegal MCR-1 plasma etch system has been electrically characterized, and the plasma impedance has been measured at 13.56MHz. Important aspects of radio-frequency (RF) impedance measurements are addressed as they pertain to the measurement of the plasma impedance. These include: transmission line effects, magnitude and phase errors of the measurement probes, and the intrinsic impedance of the empty plasma chamber. Plasma harmonics are discussed, and a technique for measuring the plasma impedance at harmonic frequencies is presented. Transients in the plasma impedance are observed during the first 5 minutes after the plasma is initiated, and represent a decrease in the plasma impedance. Residual gas analysis (RGA) confirms the presence of H₂O in the plasma. The H₂O ion current measured by RGA shows a downward transient similar to the impedance transients, suggesting a possible relationship between H₂O and the impedance transients. A possible explanation for these impedance transients is presented.
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13

Balkorkian, Sevag, and Zhang Hao. "Analysis of Internal RF Interferences in Mobile." Thesis, KTH, Microelectronics and Information Technology, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3909.

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Nowadays, mobile phones have greater functionality; a camera, color LCD screen, wireless LAN, Bluetooth, IrDA and others. In the near future wider variety of new functionalities will be added, from high quality voice, high definition video to high data rate wireless channels. As consumer electronics integrate greater functionality and high operating frequencies, their emissions will exceed the specified limits, most of these emissions will be a result of the internal interferences in the mobile phone. Moreover higher operating frequencies will be required to improve the quality of these functionalities, something that will make it more difficult to control these interferences. Internal or external sources of electromagnetic interference can degrade the performance of sensitive analog/digital circuits inside the mobile phone. Moreover the electronic device must satisfy a host of global regulations that limit it’s susceptibility to these interferences, as well as the interference emitted by the device itself.

Therefore designing a new electronic device to perform new and exciting functions will not be a pleasant task if it can not meet certain specifications and function as required to adhere to certain global regulations.

This thesis project investigates the sources of interference inside a mobile phone; mainly the electromagnetic interferences and its effect on the radio transceiver focusing on the GSM receiver sensitivity. This report is a result of intensive research, an investigation of possible sources of interference, also actual measurements were performed; RSSI, OTA and sniffing measurements; to identify the physical sources of interferences, and their effect on the receiver sensitivity. Finally solutions were recommended and implemented to suppress the interferences due to different sources, mainly through filtering, shielding or proper grounding of signals and components/subsystems in the mobile phone.

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14

Huebschman, Michael Lee. "Spectroscopic measurements in low temperature in low temperature inductively coupled RF discharges in hydrogen /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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15

Ferreira, André Mariano Silva. "Frequency characterization of single coil RF relays." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/18519.

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Mestrado em Engenharia Electrónica e Telecomunicações
Short-Open-Load-Thru (SOLT) e Thru-Re ect-Line (TRL) são as duas técnicas de calibração mais utilizadas na correcção de erros aplicada em Vector Network Analyzers (VNA). No entanto, alguns requisitos têm que ser cumpridos, de modo a permitir a aplicação destas técnicas de calibração em medições realizadas em placas de teste. Esta dissertação destina-se a caracterização em frequência de dispositivos inseridos em placas de teste, mais especificamente de relés electromecânicos de bobina única para aplicações em frequências rádio (RF) e microondas. As técnicas de calibração SOLT e TRL são inicialmente estudadas de modo a perceber os seus requisitos e limitações. De seguida, desenvolve-se e apresenta-se o desenho de standards de calibração personalizados em placas de teste. Por fim, para cada técnica de calibração, procede-se a caracterização em frequência de relés RF de bobina única e comparam-se os resultados obtidos com as curvas de desempenho típicas apresentadas pelo fabricante.
Short-Open-Load-Thru (SOLT) and Thru-Re ect-Line (TRL) are the two most common calibration techniques for the error correction applied on Vector Network Analyzers (VNA). These techniques however are not so straight forward when it comes to in- xture measurements. This dissertation is aimed at the frequency characterization of in- xture devices, speci cally single coil electromechanical relays for radio frequency (RF) and microwave applications. The SOLT and TRL calibration techniques are rst studied to understand the limitations and requirements each technique. Then the design of custom in- xture calibration standards is developed and presented for each technique. Finally, the single coil RF relays are characterized for each calibration technique and the results are compared with the typical performance presented on the datasheet.
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16

Sanchez, Carlos Alberto. "Towards single shot measurements of a Cooper pair box qubit using an rf single electron transistor." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3203.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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17

Subramani, Nandha kumar. "Physics-based TCAD device simulations and measurements of GaN HEMT technology for RF power amplifier applications." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0084/document.

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Depuis plusieurs années, la technologie de transistors à effet de champ à haute mobilité (HEMT) sur Nitrure de Gallium (GaN) a démontré un potentiel très important pour la montée en puissance et en fréquence des dispositifs. Malheureusement, la présence des effets parasites dégrade les performances dynamiques des composants ainsi que leur fiabilité à long-terme. En outre, l'origine de ces pièges et leur emplacement physique restent incertains jusqu'à aujourd'hui. Une partie du travail de recherche menée dans cette thèse est axée sur la caractérisation des pièges existant dans les dispositifs HEMTs GaN à partir de mesures de paramètre S basse fréquence (BF), les mesures du bruit BF et les mesures I(V) impulsionnelles. Parallèlement, nous avons effectué des simulations physiques basées sur TCAD afin d'identifier la localisation des pièges dans le transistor. De plus, notre étude expérimentale de caractérisation et de simulation montre que les mesures BF pourraient constituer un outil efficace pour caractériser les pièges existant dans le buffer GaN, alors que la caractérisation de Gate-lag pourrait être plus utile pour identifier les pièges de barrière des dispositifs GaN HEMT. La deuxième partie de ce travail de recherche est axée sur la caractérisation des dispositifs AlN/GaN HEMT sur substrat Si et SiC. Une méthode d’extraction simple et efficace de la résistance canal et de la résistance de contact a été mise au point en utilisant conjointement la simulation physique et les techniques de caractérisation. Le principe de l’extraction de la résistance canal est basée sur la mesure de la résistance RON. Celle-ci est calculée à partir des mesures de courant de drain IDS et de la tension VDS pour différentes valeurs de températures En outre, nous avons procédé à une évaluation complète du comportement thermique de ces composants en utilisant conjointement les mesures et les simulations thermiques tridimensionnelles (3D) sur TCAD. La résistance thermique (RTH) a été extraite pour les transistors de différentes géométries à l'aide des mesures et ensuite validée par les simulations thermiques sur TCAD
GaN High Electron Mobility Transistors (HEMTs) have demonstrated their capabilities to be an excellent candidate for high power microwave and mm-wave applications. However, the presence of traps in the device structure significantly degrades the device performance and also detriments the device reliability. Moreover, the origin of these traps and their physical location remains unclear till today. A part of the research work carried out in this thesis is focused on characterizing the traps existing in the GaN/AlGaN/GaN HEMT devices using LF S-parameter measurements, LF noise measurements and drain-lag characterization. Furthermore, we have used TCAD-based physical device simulations in order to identify the physically confirm the location of traps in the device. Moreover, our experimental characterization and simulation study suggest that LF measurements could be an effective tool for characterizing the traps existing in the GaN buffer whereas gate-lag characterization could be more useful to characterize the AlGaN barrier traps of GaN HEMT devices. The second aspect of this research work is focused on characterizing the AlN/GaN/AlGaN HEMT devices grown on Si and SiC substrate. We attempt to characterize the temperature-dependent on-resistance (RON) extraction of these devices using on-wafer measurements and TCAD-based physical simulations. Furthermore, we have proposed a simplified methodology to extract the temperature and bias-dependent channel sheet resistance (Rsh) and parasitic series contact resistance (Rse) of AlN/GaN HEMT devices. Further, we have made a comprehensive evaluation of thermal behavior of these devices using on-wafer measurements and TCAD-based three-dimensional (3D) thermal simulations. The thermal resistance (RTH) has been extracted for various geometries of the device using measurements and validated using TCAD-thermal simulations
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18

JAYASINGHE, CHAMINDA. "FUNCTIONALIZATION OF SINGLE WALL CARBON NANOTUBES USING RF-PLASMA: THE ROLE OF DEFECTS IN SIDEWALL FUNCTIONALIZATION." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1185999248.

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19

Yoho, Jason Jon III. "Design and Calibration of a RF Capacitance Probe for Non-Destructive Evaluation of Civil Structures." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/9756.

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Portland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. Non-destructive evaluation (NDE) methods are potentially among the most useful techniques developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part describes the conductivity of PCC and the attenuation of electromagnetic waves, and hence the losses within the PCC media. Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1MHz to about 40MHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation In this research, a capacitance probe has been developed for field application. The probe consists of two planar conducting plates and is made of flexible materials for placement on exposed surfaces of the specimens to be tested. The calibration method of both capacitive systems has been extensively studied to minimize systematic errors in the measurement process. These two measurement systems will be discussed and compared to one another on the basis of sensitivity and measurement repeatability.
Master of Science
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20

Usoltceva, Mariia. "Advancements in Langmuir probe diagnostic for measurements in RF sheath and in modelling of the ICRF slow wave." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0061.

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Injecter de la puissance au plasma avec les ondes au voisinage de la fréquence cyclotron ionique (ICRF) est une technique prometteuse pour chauffer les plasmas de tokamak aux températures de fusion requises. Pour le rendement élevé, l'antenne ICRF doit être placée à proximité du plasma, mais ils accroissent les interactions plasma-paroi néfastes. Les ions accélérés par le champ électrique dans la gaine radiofréquence (RF) se sont avérés être à l'origine de ces interactions. La conception de l'antenne ICRF pourrait être optimisée pour réduire les effets observés. Ces études peuvent être réalisées sur une simple expérience dédiée. Aline (A Linear Experiment) est une machine linéaire avec un plasma cylindrique à basse température que s'appuie sur la caractérisation du plasma avec la sonde de Langmuir. Le champ magnétique modifie complètement le transport de particules dans le plasma. Par conséquent, les méthodes classiques d'analyse de sondes ne sont plus applicables. Cela est particulièrement vrai pour une sonde de Langmuir cylindrique de petit diamètre parallèle au champ magnétique ou avec un petit angle avec celui-ci. Les théories développées pour le traitement des données de la sonde de Langmuir pour le plasma magnétisé sont présentés. Les résultats sont comparés aux densités obtenues par interférométrie. Les techniques d'analyse des données présentées sont non seulement importantes pour l'application sur Aline, mais aussi pour d’autre machines à plasma magnétisé. IShTAR (Ion cyclotron Sheath Test Arrangement) fournit des conditions plus proches de celles du tokamak que celles d'Aline car possédant une antenne ICRF imitant celles d'un tokamak. L'objectif est d'étudier la propagation des ondes ICRF dans la configuration IShTAR. Les diagnostics de sonde ont été utilisés pour quantifier les paramètres plasma et les champs des ondes ICRF pertinents. Des simulations numériques de l'onde lente ICRF ont été réalisées à COMSOL. Le plasma a été mis en œuvre en tant que matériau avec des propriétés physiques ajustées manuellement. Les structures de champ obtenues pour l'onde lente diffèrent significativement de celles de l'onde rapide (autre solution de la relation de dispersion), et présentent une forte dépendance du profil de densité sur le bord du plasma. Les résultats de cette thèse contribuent aux études de la physique de la gaine RF sur des dispositifs linéaires dédiés, ainsi que de la physique des ondes ICRF sur le bord du plasma du tokamak en général
Coupling power to the plasma with ion cyclotron range of frequencies (ICRF) waves is a promising method for heating tokamak plasmas to fusion relevant temperatures. For high efficiency, the ICRF antenna must be placed close to the plasma, but they enhance destructive plasma-wall interactions. Plasma ions accelerated by the electric field in the radio-frequency (RF) sheath have been found to be the main cause of these interactions. The ICRF antenna design could be optimized to reduce the observed effects. The physics of these effects can be studied on a simple specially designed experiment. Aline (A LINear Experiment) is a linear low-temperature plasma device. The machine is focused on plasma characterization with the Langmuir probe diagnostic. The presence of magnetic field changes completely the particle transport in plasma, therefore conventional methods of data analysis are not applicable. Especially it is true for a small cylindrical Langmuir probe parallel to the magnetic field or at a small angle to it. In this thesis theories are presented which were developed for Langmuir probe data processing for magnetized plasma. The first results are also presented, as well as a comparison to line-averaged densities by interferometry. Presented data analysis techniques are not only important for application on Aline but can be used on any machine with magnetized plasma. IShTAR (Ion cyclotron Sheath Test Arrangement) is closer to tokamak conditions than Aline because it has an ICRF antenna which mimics tokamak antennas. In the framework of this thesis the objective is to study comprehensively the ICRF wave propagation in IShTAR configuration. Probe diagnostics were employed to quantify the relevant plasma parameters and the relevant ICRF wave fields. Numerical simulations of the ICRF slow wave were done in COMSOL. Plasma was implemented as a material with manually assigned physical properties. Field structures obtained for the slow wave differ significantly from the other mode, fast wave, and exhibit strong dependence on the density profile on the plasma edge. The results of this thesis work contribute to the studies of the RF sheath physics on dedicated linear devices, as well as the physics of ICRF waves on the tokamak plasma edge in general. In ICRF simulations for tokamak devices the slow wave propagation on the edge is avoided. Results of this thesis can be used to improve the complex tokamak ICRF simulations
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21

Adegoke, Elijah. "Radio frequency channel characterization for energy harvesting in factory environments." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33412.

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This thesis presents ambient energy data obtained from a measurement campaign carried out at an automobile plant. At the automobile plant, ambient light, ambient temperature and ambient radio frequency were measured during the day time over two days. The measurement results showed that ambient light generated the highest DC power. For plant and operation managers at the automobile plant, the measurement data can be used in system design considerations for future energy harvesting wireless sensor nodes at the plant. In addition, wideband measurements obtained from a machine workshop are presented in this thesis. The power delay profile of the wireless channel was obtained by using a frequency domain channel sounding technique. The measurements were compared with an equivalent ray tracing model in order to validate the suitability of the commercial propagation software used in this work. Furthermore, a novel technique for mathematically recreating the time dispersion created by factory inventory in a radio frequency channel is discussed. As a wireless receiver design parameter, delay spread characterizes the amplitude and phase response of the radio channel. In wireless sensor devices, this becomes paramount, as it determines the complexity of the receiver. In reality, it is sometimes difficult to obtain full detail floor plans of factories for deterministic modelling or carry out spot measurements during building construction. As a result, radio provision may be suboptimal. The method presented in this thesis is based on 3-D fractal geometry. By employing the fractal overlaying algorithm presented, metallic objects can be placed on a floor plan so as to obtain similar radio frequency channel effects. The environment created using the fractal approach was used to estimate the amount of energy a harvesting device can accumulate in a University machine workshop space.
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22

Casbon, Michael Anthony. "Design and application of an advanced fully active harmonic load pull system using pulsed RF measurements and synchronised laser energy." Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/115731/.

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The objective of this work was to advance the design of Active Harmonic Load-Pull systems to facilitate accurate modelling of RF semiconductors, with specific regard to time dependant behaviours. Pulse capability is added, to extend the thermally safe operating region, investigate thermal behaviour, and reduce the thermal loading on the system components. The safe operation region extension is demonstrated with a GaAs die, the thermal aspects of behaviour are illustrated with GaN on SiC, GaN on Si and GaN on diamond die. A violet laser is added, which releases some types of trapped charge, helping to reveal the full potential of the device. The thermal transient response of the device is thereby exposed, and the trap filling times may be studied. The application of this to GaN die with and without Source Coupled Field Plates is described. The relevance of the light wavelength is briefly investigated. A novel wafer probe station is described, providing access to the backside of the wafer for photonic trap release and the measurement of hot electron electroluminescence, as RF measurements are conducted on the front side. Replacing the drain RF and DC circuits with a fixed resistor, and stepping the gate voltage allows the device to be held at any point on the load-line and then moved to another, here this demonstrates that the residual “knee-walkout” on a GaN on SiC part with an optimised source coupled field plate is not a thermal effect, and must therefore be due to trapped charge, despite the field plate. A low loss diplexer/ bias tee combination with very good DC supply memory properties is described, demonstrated with a InAlN/GaN die at Ka band. Accurate measurement of harmonics is vital to waveform engineering. Here a novel method of increasing the effective dynamic range of the system is presented.
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23

Kumar, Akshay. "Measurement of Antenna Performance in Analog LMR Systems Using PL Tone Analysis." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/46188.

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We are interested in measuring the in situ antenna performance in analog land mobile radio (LMR) FM systems. The gain (efficiency and directivity) and self-impedance of an antenna sufficiently characterize its performance and a number of traditional methods exist to measure these quantities. However it is hard to do antenna gain measurements using these methods. Furthermore, it turns out that volumetric antenna gain measurements are not quite relevant for understanding in situ performance. In this thesis, we present a novel approach for directly measuring the in situ performance of antennas in analog LMR systems. The procedure involves receiving an FM signal simultaneously using the antenna under test (AUT) and a reference antenna. Both received signals are demodulated to audio using separate but identical receivers. Then a convenient method for characterizing the audio signal quality is to analyze the private line (PL) tone. The PL tone signal-to-noise ratio (SNR) is calculated by measuring the power of the tone relative to the sub-audio noise power. The PL tone SNR for both antenna systems is compared as it provides a ``bottom line'' evaluation of the antenna performance. The audio SNR can also be mapped to RF SNR using a theoretical method. From simulation and experimental studies, we conclude that the RF SNR estimated using this technique is within 0.5 dB of the actual value for RF SNR values between +3 and +36 dB. Finally, we demonstrate this procedure in actual in situ LMR antenna measurements.
Master of Science
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24

Barbagallo, Carmelo. "Design and optimization of higher order mode couplers for the superconducting cavities of the PERLE energy recovery linac." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP092.

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PERLE (Powerful Energy Recovery Linac for Experiments) est un accélérateur linéaire à recouvrement d'énergie (ERL) basé sur la technologie à cavité radiofréquence supraconductrice qui sera installé au Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab) en France. Avec une puissance de faisceau cible de 10 MW, PERLE vise à démontrer le fonctionnement multi-passe à haute intensité en onde continue pour valider des options pour les futures machines à haute énergie, telles que l'ERL de 50 GeV proposé pour LHeC (Large Hadron Electron Collider) et FCC-eh (Future Circular Electron-Hadron Collider), et à accueillir des expériences dédiées en physique des particules et en nucléaire. Dans les ERLs à haute intensité, l'instabilité de Beam Breakup (BBU), résultant de l'interaction entre le faisceau et les modes d'ordre supérieur (HOMs) des cavités, est une préoccupation majeure pour leur fonctionnement stable. Les HOMs induits par le faisceau peuvent augmenter la charge thermique de la cavité à température cryogénique et causer des instabilités du faisceau. Des coupleurs HOM sont installés dans les tubes de faisceau de la cavité pour absorber l'énergie des HOMs et atténuer ces effets. Cette thèse présente la conception et l'optimisation de plusieurs coupleurs HOM coaxiaux pour les cavités elliptiques en Nb avec 5 cellules à 801,58 MHz de la configuration PERLE ERL à 500 MeV. La transmission RF des coupleurs HOM a été optimisée pour améliorer l'amortissement des HOMs les plus dangereux. Les coupleurs HOM optimisés ont été intégrés dans des groupes d'extrémité pour simuler leur performance d'amortissement et leur comportement thermique. Les coupleurs HOM optimisés ont été imprimés en 3D en époxy et revêtus de cuivre. Des mesures RF à faible puissance ont été effectuées sur les coupleurs HOM produits installés dans des cavités en cuivre de type PERLE pour valider leur performance d'amortissement et proposer plusieurs groupes d'extrémité pour la cavité PERLE avec 5 cellules afin d'atténuer les HOMs en dessous des limites d'instabilité BBU
The Powerful Energy Recovery Linac for Experiments (PERLE) is an energy recovery linac (ERL) facility based on superconducting radio-frequency (SRF) technology to be hosted at the Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab) in France. With a target beam power of 10~MW, PERLE aims to demonstrate the high-current, continuous wave, multi-pass operation to validate options for future high-energy machines, such as the 50 GeV ERL proposed for the Large Hadron Electron Collider (LHeC) and the Future Circular Electron-Hadron Collider (FCC-eh), and host dedicated particle physics and nuclear experiments. In high-current ERLs, the regenerative Beam Breakup (BBU), emerging from the beam and cavity Higher Order Modes (HOMs) interaction, is a major concern for their stable operation. Beam-induced HOMs can increase the cavity heat load at cryogenic temperature and cause beam instabilities. HOM couplers are installed in the cavity beam pipes to absorb HOM energy and mitigate these effects. This thesis presents the design and optimization of several coaxial HOM couplers for the 5-cell 801.58 MHz elliptical Nb cavities of the 500 MeV PERLE ERL configuration. The RF transmission of the HOM couplers was optimized to enhance the damping of the most dangerous HOMs. The optimized HOM couplers were integrated into endgroups to simulate their damping performance and thermal behavior. The optimized HOM couplers were 3D-printed in epoxy and copper-coated. Low-power RF measurements were conducted on the produced HOM couplers installed in copper PERLE-type cavities to validate their damping performance and propose several endgroups for the PERLE 5-cell cavity to mitigate HOMs below the BBU instability limits
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25

Volfbeyn, Pavel S. "Measurements of the temporal and spatial phase variations of a 33 GHz pulsed free electron laser amplifier and application to RF acceleration." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37785.

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26

Thompson, Dane C. "Characterization and Design of Liquid Crystal Polymer (LCP) Based Multilayer RF Components and Packages." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10498.

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This thesis discusses the investigation and utilization of a new promising thin-film material, liquid crystal polymer (LCP), for microwave and millimeter-wave (mm-wave [>30 GHz]) components and packages. The contribution of this research is in the determination of LCP's electrical and mechanical properties as they pertain to use in radio frequency (RF) systems up to mm-wave frequencies, and in evaluating LCP as a low-cost substrate and packaging material alternative to the hermetic materials traditionally desired for microwave circuits at frequencies above a few gigahertz (GHz). A study of LCP's mm-wave material properties was performed. Resonant circuit structures were designed to find the dielectric constant and loss tangent from 2-110 GHz under both ambient and elevated temperature conditions. Several unique processes were developed for the realization of novel multilayer LCP-based RF circuits. These processes include thermocompression bonding with tight temperature control (within a few degrees Celsius), precise multilayer alignment and patterning, and LCP laser processing with three different types of lasers. A proof-of-concept design that resulted from this research was a dual-frequency dual-polarization antenna array operating at 14 and 35 GHz. Device characterization such as mechanical flexibility testing of antennas and seal testing of packages were also performed. A low-loss interconnect was developed for laser-machined system-level thin-film LCP packages. These packages were designed for and measured with both RF micro-electromechanical (MEM) switches and monolithic microwave integrated circuits (MMICs). These research findings have shown LCP to be a material with uniquely attractive properties/capabilities for vertically integrated, compact multilayer LCP circuits and modules.
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27

Galindo, Muñoz Natalia. "Development of direct measurement techniques for the in-situ internal alignment of accelerating structures." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/100488.

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Las exigentes tolerancias de alineación en los componentes de los futuros colisionadores lineales de partículas requieren el desarrollo de nuevas técnicas de alineación más precisas que las existentes. Este es el caso del Colisionador Lineal Compacto (Compact Linear Collider, CLIC), cuyos objetivos altamente restrictivos de alineamiento alcanzan los 10 um. Para poder lograr el máximo rendimiento del acelerador, es necesario que el posicionamiento de las estructuras que aceleran las partículas y de los campos que las guían cumplan las tolerancias de alineación para dirigir el haz a lo largo de la trayectoria diseñada. Dicho procedimiento consiste en relacionar la posición de los ejes de referencia de cada componente con respecto a objetos externos, o fiduciales, lo cual resulta muy tedioso y económicamente costoso. Los errores sistemáticos y aleatorios se van acumulando en cada paso del proceso y, en consecuencia, la precisión final de alineamiento es todo un desafío. En este contexto, nace el proyecto PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometre scale), subvencionado por la Unión Europea en el programa FP7 de financiación para la investigación e innovación. El objetivo principal de PACMAN es investigar, desarrollar e implementar una solución integrada alternativa que incorpore todos los pasos de alineación en una misma ubicación, con el objetivo de mejorar la precisión de alineación de los componentes de los aceleradores, en concreto: las estructuras aceleradoras, los cuadrupolos y los monitores de posición de haz. La viabilidad de las soluciones desarrolladas y la precisión de alineamiento alcanzada deben de demostrarse en un banco de pruebas utilizando componentes de CLIC. La estrategia de PACMAN para alcanzar el objetivo técnico se divide en tres pasos. El primero consiste en la fiducialización de los componentes y sus soportes. El segundo paso es el ensamblaje de los componentes en dos tipos de soporte, uno compuesto por un monitor de posición de haz y un cuadrupolo, y otro con cuatro estructuras aceleradoras, tomando como referencia su centro electromagnético. Finalmente, ambos soportes se transportan al túnel para su alineación final utilizando técnicas de hilos tensados. En esta tesis doctoral, se describe el desarrollo de una nueva técnica no destructiva para localizar los ejes electromagnéticos de estructuras aceleradoras y su validación experimental. Para ello, se ha utilizado una estructura aceleradora de CLIC conocida como TD24. Debido a la complejidad mecánica de la TD24, su difícil acceso y su diámetro medio de iris de 5.5 mm, se desarrolla una nueva técnica denominada en esta tesis como 'el método perturbativo' y se realiza una propuesta experimental de validación. El estudio de viabilidad de este método, cumpliendo con los requisitos impuestos de precisión en la medida de 10 um, ha sido realizado con una campaña extensa de simulaciones de campos electromagnéticos en tres dimensiones utilizando la herramienta de software conocida como HFSS. Los resultados de simulación han permitido el desarrollo de un algoritmo muy completo de medidas y han proporcionado las especificaciones técnicas para el diseño conceptual de un banco de pruebas para la medida de los ejes electromagnéticos de la TD24. El preciso ensamblaje del banco de pruebas y sus correspondientes calibraciones, la incorporación de nuevos tratamientos de las medidas en el algoritmo final y la caracterización de fuentes de error en la medida, favorecieron la localización del centro electromagnético en la TD24 con una precisión menor a 1 um con un error estimado menor que 8.5 um, cumplimiendo con los objetivos de precisión establecidos.
In the next generation of linear particle accelerators, challenging alignment tolerances are required in the positioning of the components focusing, accelerating and detecting the beam over the accelerator length in order to achieve the maximum machine performance. In the case of the Compact Linear Collider (CLIC), accelerating structures, beam position monitors and quadrupole magnets need to be aligned in their support with respect to their reference axes with an accuracy of 10 um. To reach such objective, the PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometer Scale) project strives for the improvement of the current alignment accuracy by developing new methods and tools, whose feasibility should be validated using the major CLIC components. This Ph.D. thesis concerns the investigation, development and implementation of a new non-destructive intracavity technique, referenced here as 'the perturbative method', to determine the electromagnetic axes of accelerating structures by means of a stretched wire, acting as a reference of alignment. Of particular importance is the experimental validation of the method through the 5.5 mm iris-mean aperture CLIC prototype known as TD24, with complex mechanical features and difficult accessibility, in a dedicated test bench. In the first chapter of this thesis, the alignment techniques in particle accelerators and the novel proposals to be implemented in the future linear colliders are introduced, and a detailed description of the PACMAN project is provided. The feasibility study of the method, carried out with extensive electromagnetic fields simulations, is described in chapter 2, giving as a result, the knowledge of the theoretical accuracy expected in the measurement of the electromagnetic axes and facilitating the development of a measurement algorithm. The conceptual design, manufacturing and calibration of the automated experimental set-up, integrating the solution developed to measure the electromagnetic axes of the TD24, are covered in chapter 3. The future lines of research and developments of the perturbative method are also explored. In chapter 4, the most significant results obtained from an extensive experimental work are presented, analysed and compared with simulations. The proof-of-principle is completed, the measurement algorithm is optimised and the electromagnetic centre is measured in the TD24 with a precision less than 1 um and an estimated error less than 8.5 um. Finally, in chapter 5, the developments undertaken along this research work are summarised, the innovative achievements accomplished within the PACMAN project are listed and its impact is analysed.
En la generació pròxima d'acceleradors de partícules lineals, desafiant toleràncies d'alineament és requerit en el posicionament dels components que enfoquen, accelerant i detectant la biga sobre la longitud d'accelerador per tal d'aconseguir l'actuació de màquina màxima. En el cas del Colisionador Compacte Lineal (CLIC), accelerant estructures, monitors de posició de fes i imants necessiten ser alineats en el seu suport amb respectar a les seves destrals de referència amb una precisió de 10 um. Per assolir tal objectiu, el PACMAN (Metrologia de Components de l'Accelerador de partícules i Alineament al Nanometer Escala) projecte s'esforça per la millora de l'actual precisió d'alineament per mètodes nous en desenvolupament i eines, la viabilitat dels quals hauria de ser validada utilitzant els components de CLIC importants. Aquesta tesi concerneix la investigació, desenvolupament i implementació d'un nou no-destructiu tècnica interna, va referenciar ací mentre 'el mètode de pertorbació' per determinar les destrals electromagnètiques d'accelerar estructures mitjançant un cable estès, actuant com a referència d'alineament. De la importància particular és la validació experimental del mètode a través del 5.5 mm iris-roí obertura prototipus de CLIC sabut com TD24, amb característiques mecàniques complexes i accessibilitat difícil, en un banc de prova dedicat. En el primer capítol d'aquesta tesi, les tècniques d'alineament en acceleradors de partícules i les propostes novelles per ser implementades en el futur colisionador lineal és introduït, i una descripció detallada del projecte PACMAN és proporcionat. L'estudi de viabilitat el mètode de pertorbació, va dur a terme amb simulacres de camps electromagnètics extensos, és descrit dins capitol 2, donant com a resultat, el coneixement de la precisió teòrica esperada en la mida de les destrals electromagnètiques i facilitant el desenvolupament d'un algoritme de mida. El disseny conceptual, fabricació i calibratge del conjunt experimental automatitzat-amunt, integrant la solució desenvolupada per mesurar les destrals electromagnètiques del TD24, és cobert dins capitol 3. Les línies futures de recerca i desenvolupaments del mètode és també va explorar. Dins capitol 4, la majoria de resultats significatius van obtenir d'una faena experimental extensa és presentada, analitzat i comparat amb simulacres. La prova-de-el principi és completat, l'algoritme de mida és optimitzat i el centre electromagnètic és mesurat en el TD24 amb una precisió menys d'1 um i un error calculat menys de 8.5 um. Finalment, dins capitol 5, els desenvolupaments empresos al llarg d'aquesta faena de recerca és resumit, les consecucions innovadores van acomplir dins del projecte PACMAN és llistat i el seu impacte és analitzat.
Galindo Muñoz, N. (2018). Development of direct measurement techniques for the in-situ internal alignment of accelerating structures [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/100488
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28

Bhusal, Bhumi Shankar. "Radiofrequency Induced Heating of Implanted Stereo-electroencephalography Electrodes During MRI Scan: Theory, Measurements and Simulations." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1545139929613149.

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29

Slim, Jamal Verfasser], Dirk [Akademischer Betreuer] [Heberling, Kay [Akademischer Betreuer] Hameyer, and Jörg [Akademischer Betreuer] Pretz. "A novel waveguide RF Wien filter for electric dipole moment measurements of deuterons and protons at the COoler SYnchrotron (COSY)/Jülich / Jamal Slim ; Dirk Heberling, Kay Hameyer, Jörg Johannes Pretz." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069465/34.

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30

Slim, Jamal [Verfasser], Dirk [Akademischer Betreuer] Heberling, Kay [Akademischer Betreuer] Hameyer, and Jörg [Akademischer Betreuer] Pretz. "A novel waveguide RF Wien filter for electric dipole moment measurements of deuterons and protons at the COoler SYnchrotron (COSY)/Jülich / Jamal Slim ; Dirk Heberling, Kay Hameyer, Jörg Johannes Pretz." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069465/34.

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31

Ledig, Jordan. "Étude des structures de courant et de potentiel autour d’une antenne radio-fréquence dans un plasma magnétisé." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0082.

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La fusion thermonucléaire contrôlée est une solution envisageable pour la production d’une énergie propre quasi inépuisable pour les générations à venir. Cependant, les températures requises pour procéder à la fusion des noyaux sont de l’ordre de la centaine de millions de degrés. À ces températures la matière se trouve dans l’état de plasma, un gaz ionisé, ce qui nous permet de le confiner dans des champs magnétiques puissants. Parmi les moyens de chauffage utilisés dans les réacteurs à fusion magnétique (les Tokamaks et les Stellarator), nous nous intéresserons au chauffage par résonance cyclotron ionique via des antennes émettant un champ électromagnétique dans la gamme des radio-fréquences. La compréhension du comportement du plasma autour de ces antennes ICRH ou plus généralement en présence d’ondes RF et d’un champ magnétique est un enjeu majeur pour minimiser les flux de particules accélérées dans les gaines RF au contact d’une antenne ou d’une électrode. Le réacteur expérimental ALINE (a linear experiment) a été justement conçu dans le but d’étudier les gaines RF et les structures se générant autour des antennes. Cette thèse présente les résultats expérimentaux obtenus dans ALINE par le biais de mesures de sonde de Langmuir. Un bras manipulateur permet de bouger automatiquement la sonde dans toute l’enceinte, et de dresser une cartographie des paramètres du plasma. Après avoir étudié en profondeur le problème des mesures de sonde sous champ (surface effective de collection électronique, caractéristiques bossues), la mise au point d’un algorithme itératif d’exploitation du courant ionique de saturation des caractéristiques de sonde a permis d’exploiter automatiquement toutes les données acquises. Les mesures sont confrontées à plusieurs théories et simulations, afin de modéliser et de comprendre au mieux les structures de paramètres plasma en face d’une électrode RF inclinée par rapport aux lignes de champ magnétique
Controlled thermonuclear fusion is a possible solution for the production of almost inexhaustible clean energy for future generations. However, the temperatures required to carry out the fusion of the nuclei are of the order of one hundred million degrees. At these temperatures matter is in the state of plasma, an ionized gas, which allows us to confine it in strong magnetic fields. Among the heating means used in magnetic fusion reactors (Tokamaks and Stellarators), we will be interested in ion cyclotron resonance heating via antennas emitting an electromagnetic field in the radio frequencies range. Understanding the behavior of plasma around these ICRH antennas or more generally in the presence of RF waves and a magnetic field is a major issue to minimize the flow of accelerated particles in RF sheaths in contact with an antenna or an electrode. The ALINE experimental reactor (a linear experiment) was precisely designed with the aim of studying the RF sheaths and the structures generated around the antennas. This thesis presents the experimental results obtained in ALINE by means of Langmuir probe measurements. A manipulator arm makes allows us to automatically move the probe within the wole device, and to draw up a map of the plasma parameters. After having studied in depth the problem of probe measurements under field (effective surface of electronic collection, bumped characteristics), the development of an iterative algorithm of exploitation only using the ionic saturation current of the probe characteristics made it possible to exploit automatically all acquired data. The measurements are confronted with several theories and simulations, in order to model and to better understand the plasma parameter structures in front of an RF electrode inclined with respect to the magnetic field lines
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Gomes, José Miguel Alves Faria. "Characterization and modelling of long-term memory effects in GaN HEMTs." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/18456.

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Mestrado em Engenharia Eletrónica e de Telecomunicações
Gallium nitride (GaN) high electron mobility transistor (HEMT) technology has been revolutionizing the RF power amplifier (PA) market. Its potential, versus existing technologies, such as Silicon (Si) Laterally-Diffused MOS(LDMOS), is yet to be completely explored. However, the lack of good characterization and modelling of charge carrier trapping related phenomena has been hampering PA designers from extracting this technology’s promised performance. Hence, GaN HEMT trapping has been given a great amount of attention by the scientific and industrial worlds. This is mainly because the overall linearity of the PA built with this technology is affected, to a great extent, by the trapping state dependence on the device’s drain peak voltage. Circuit computer-aided design (CAD) tools are almost ubiquitous at research and development labs. However, these tools rely, not only on their simulation algorithms, but also on their built-in device models. This makes the development of accurate models a fundamental task. This work reports a multi-bias small-signal equivalent circuit (SSEC) model extraction procedure of a 3.3 W GaN HEMT from pulsed S-parameters as well as the development of a pulsed DC I-V measurement system and its use in the characterization of trapping-effects. This system, which is based on two pulser circuits, designed specifically for gate and drain pulsed measurements, was then automated through a MATLAB/PC controller. The pulser circuits allowed pulse widths on the microsecond scale at very low duty cycles as well as high peak voltages - close to 50 V - and currents - up to 4 A. With the developed system, isothermal standard pulsed I-V curves, as well as trapping-state dependent, isodynamic, pulsed I-V curves were obtained from a 15 W GaN HEMT device. In order to obtain the latter, the so-called double-pulse measurement technique was used. The expected asymmetric time constants associated with drain-lag were clearly observed: on the ns scale for the trapping and on the hundreds of milliseconds for the de-trapping. The predicted relatively reduced impact of gate-lag phenomena in more recent GaN HEMT technologies was also verified.
A tecnologia GaN HEMT tem revolucionado o mercado dos amplificadores de potência para RF. O seu potencial, comparado com tecnologias anteriores, como a Si LDMOS, continua por ser completamente explorado. Contudo, a falta de uma boa caracterização e modelação dos efeitos de memória lenta causados pelo armadilhamento de cargas têm impedido o total aproveitamento desta tecnologia no desenho de amplificadores de potência. Consequentemente, estes fenómenos de armadilhamento têm sido alvo de um amplo estudo tanto a nível científico como industrial. Isto deve-se, sobretudo, porque a linearidade dos amplificadores baseados nesta tecnologia é bastante afectada pelo estado de armadilhamento de cargas no dispositivo, que, por sua vez, é definido pela tensão de pico na saída, drain, do transístor. As ferramentas de desenho de circuitos auxiliado por computador estão presentes na maioria dos laboratórios de investigação. No entanto, estas dependem não só dos seus algoritmos de simulação mas também, em larga medida, dos modelos nelas utilizados, tornando fundamental o desenvolvimento de melhores modelos. O presente documento descreve a extracção de um modelo de circuito equivalente de pequeno signal dependente da polarização, de um transístor GaN HEMT de 3.3 W, a partir de medidas de parâmetros-S pulsadas, assim como a construcção de um sistema de medidas pulsadas DC I-V e a utilização deste último na caracterização de efeitos de armadilhamento. O sistema desenvolvido, baseado em dois circuitos pulsadores desenhados para medidas pulsadas quer no terminal de entrada, gate, quer no de saída, drain, foi automatizado através do software MATLAB instalado num PC. Os circuitos pulsadores permitem larguras de pulso na escala dos microsegundos com duty-cycles tão pequenos como 0.001%, assim como, elevadas tensões de saída - perto de 50 V - e correntes - pelo menos até 4 A. Com o sistema desenvolvido, obtiveram-se curvas I-V iso-térmicas e também curvas I-V iso-dinâmicas, dependentes do estado de armadilhamento, de um transístor GaN HEMT de 15 W. De modo a obter as últimas, foram utilizadas medidas de duplo-pulso. A assimetria esperada nas constantes de tempo associadas com o drain-lag foram claramente observadas: na escala dos ns para o armadilhamento e das centenas de milisegundos para o desarmadilhamento. Tal como a literatura prevê para tecnologias mais recentes de GaN HEMTs, o impacto dos fenónemos de gate-lag que foi observado revelou-se bastante reduzido.
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33

Walikewitz, Nadine. "Urban Climate and Heat Stress Hazards - an Indoor Perspective." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18765.

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Hitzestress beeinflusst nicht nur das Wohlbefinden, sondern vor allem auch die menschliche Gesundheit. Während Hitzestress im Außenraum bereits detailliert untersucht wurde, gibt es nur wenige Studien, welche sich mit thermischen Belastungen im Innenraum befassen. Dabei hält sich die Bevölkerung der Industriestaaten im Durchschnitt durchschnittlich 90 % des Tages im Innenraum auf. Analysen der klimatischen Bedingungen im Innenraum sind essenziell, um zugrundeliegende Prozesse zu verstehen, die Auswirkungen auf den Menschen zu erfassen und passende Anpassungsstrategien entwickeln zu können. Ziel der Arbeit ist es daher, verschiedene Innenraumklimata zu untersuchen und zu bewerten. Zur Untersuchung ihrer Charakteristika wurden Räume ohne Nutzerverhalten innerhalb eines Gebäudes bemessen und analysiert. Die Ergebnisse wurden dann verwendet, um ein detailliertes Innenraummesssystem zu entwickelt und an verschiedenen Standorten in Berlin aufzubauen. Die erhobenen Daten wurden dann verwendet, um die Variabilität von Hitzestress im Innenraum zeitlich und räumlich anhand des UTCI (Universal Thermal Climate Index) zu untersuchen. Den Abschluss bilden umfangreiche Analysen zu den Einflüssen von Innenraum- und Außenraumtemperaturen auf die Mortalität mittels Generalisierter Additiver Modelle (GAM). Die Ergebnisse zeigen, dass Hitzestress im Innenraum eine ernstzunehmende Gefahr darstellt. Alle Untersuchungsräume weisen hohe thermische Belastungen auf. UTCI Werte im Innenraum schwanken innerhalb eines Gebäudes und weisen im Vergleich zum Außenraum sehr hohe Belastungswerte während der Nacht auf. Die höchsten Werte wurden in modernen Gebäuden mit großen Fensterflächen ermittelt. Bezüglich der unterschiedlichen Einflussfaktoren auf das Innenraumklima konnte das Außenklima als wichtigste Einflussgröße bestätigt werden. Des Weiteren zeigt sich, dass die Innenraumtemperatur im Vergleich zur Außenraumtemperatur ein ebenso guter Prädiktor für Mortalität ist.
Heat stress influences not only the comfort of humans but also human health. Heat stress in outdoor environments has been investigated extensively, whereas only a few studies have focused on indoor environments. People in industrialized countries spend approximately 90 % of their day in confined spaces. Analyses of indoor climatic conditions are essential to understanding the underlying processes, determining the impacts on humans and developing appropriate adaptation measures. The aim of this work is to investigate and assess different indoor climates and provide a valuable contribution to future research questions. To analyze indoor climate characteristics or, rather, the influence of different meteorological parameters, the indoor climate in four rooms in one building without user behavior was measured and examined. The results were used to establish a detailed indoor measurement system at different study sites distributed over Berlin. The gathered data were then used to assess indoor heat stress variability on a temporal and spatial scale using the UTCI (Universal Thermal Climate Index). Finally, an extensive analysis of the influence of indoor climate and outdoor climate on mortality was conducted by applying generalized additive models (GAM). The results indicate that indoor heat stress is a severe threat. All study rooms experienced high thermal loads, regardless of the building type they were located in or their location within the building. Indoor UTCI values varied within buildings and further exhibited very high heat stress levels during night compared to outdoors. The highest values were measured in modern buildings with a high percentage of windows. Among the different driving factors of indoor climate, outdoor climate was confirmed to have the highest impact. Moreover, this thesis shows that indoor air temperature is an equally good predictor of mortality compared to outdoor climate.
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Lucas, de Peslouan Pierre-Olivier. "Conception orientée délai : étude, développement et réalisation d’une boucle à verrouillage de phase large bande stabilisée par une boucle à verrouillage de délai." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14265/document.

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L’explosion du marché des télécommunications a donné lieu, lors de ces dernières années, à la multiplication des standards de radiocommunication. De nos jours, l’ensemble de ces moyens de communication utilisés pour le transfert de voix et de données doit être intégré dans les terminaux mobiles. Cependant, cette tendance s’oppose aux contraintes de faible coût qui tendent à diminuer la taille de l’électronique embarquée dans un terminal mobile, mais aussi aux contraintes de diminution de la consommation pour une plus grande autonomie des objets sans fils. C’est donc autour de ces verrous technologiques et techniques que se concentre une part importante des efforts de « R&D » aujourd’hui. Ainsi, l’objectif des travaux présentés repose sur la recherche et le développement d'une architecture contribuant à l’amélioration des performances du bloc central de la chaîne d’émission/réception : l'oscillateur local.L’architecture innovante de synthétiseur de fréquence multistandard réalisée est fondée sur le principe de « conception orientée délai » (DOD - Delay Oriented Design). Une nouvelle technique de stabilisation, issue de la superposition d’une boucle à verrouillage de délai et de phase, est proposée afin d’élargir la bande passante.De l’étude système à la mesure en passant par l’étude comportementale et la réalisation du circuit, les différentes étapes de conception de ce système fractionnaire sont présentées. Les simulations et les mesures ont démontré la capacité du synthétiseur à couvrir une bande comprise entre 1,6 et 3,5GHz avec un signal de référence à 500MHz, mais aussi à stabiliser une architecture très large bande
The explosion of the wireless communication market is largely responsible of the expansion for RF communication standards for voice and data. Nowadays, each one of them must be integrated in one mobile terminal.However, this trend is opposed to the constraints of low cost, which tend to reduce the size of the electronics in a mobile terminal, but also the constraints of reduced consumption for greater autonomy for wireless systems. It is then around these technological and technical barriers that focus an important part of efforts to « R & D » today. Thus, the objective of the work presented is based on research and development of an architecture that contributes to improve the performances of the central block of transceivers: the local oscillator.The innovative architecture of multistandard synthesizer realized is based on the principle of Delay Oriented Design (DOD). A new technique of stabilization, based on the superposition of a delay and a phase locked loop, is proposed to expand the bandwidth. From study system to measurements through the behavioral comportment and implementation of the circuit, the various stages when designing an RF system are presented. Simulations and measurements have demonstrated the ability of the synthesizer to cover a frequency band between 1.6 and 3.5 GHz with a reference signal at 500MHz, but also to stabilize a broadband architecture
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35

Venkataraman, Sunitha. "Systematic Analysis of the Small-Signal and Broadband Noise Performance of Highly Scaled Silicon-Based Field-Effect Transistors." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16232.

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The objective of this work is to provide a comprehensive analysis of the small-signal and broadband noise performance of highly scaled silicon-based field-effect transistors (FETs), and develop high-frequency noise models for robust radio frequency (RF) circuit design. An analytical RF noise model is developed and implemented for scaled Si-CMOS devices, using a direct extraction procedure based on the linear two-port noise theory. This research also focuses on investigating the applicability of modern CMOS technologies for extreme environment electronics. A thorough analysis of the DC, small-signal AC, and broadband noise performance of 0.18 um and 130 nm Si-CMOS devices operating at cryogenic temperatures is presented. The room temperature RF noise model is extended to model the high-frequency noise performance of scaled MOSFETs at temperatures down to 77 K and 10 K. Significant performance enhancement at cryogenic temperatures is demonstrated, indicating the suitability of scaled CMOS technologies for low temperature electronics. The hot-carrier reliability of MOSFETs at cryogenic temperatures is investigated and the worst-case gate voltage stress condition is determined. The degradation due to hot-carrier-induced interface-state creation is identified as the dominant degradation mechanism at room temperature down to 77 K. The effect of high-energy proton radiation on the DC, AC, and RF noise performance of 130 nm CMOS devices is studied. The performance degradation is investigated up to an equivalent total dose of 1 Mrad, which represents the worst case condition for many earth-orbiting and planetary missions. The geometric scaling of MOSFETs has been augmented by the introduction of novel FET designs, such as the Si/SiGe MODFETs. A comprehensive characterization and modeling of the small-signal and high-frequency noise performance of highly scaled Si/SiGe n-MODFETs is presented. The effect of gate shot noise is incorporated in the broadband noise model. SiGe MODFETs offer the potential for high-speed and low-voltage operation at high frequencies and hence are attractive devices for future RF and mixed-signal applications. This work advances the state-of-the-art in the understanding and analysis of the RF performance of highly scaled Si-CMOS devices as well as emerging technologies, such as Si/SiGe MODFETs. The key contribution of this dissertation is to provide a robust framework for the systematic characterization, analysis and modeling of the small-signal and RF noise performance of scaled Si-MOSFETs and Si/SiGe MODFETs both for mainstream and extreme-environment applications.
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36

McCreesh, Zita M. "Short range, RF telemetry for physiological temperature acquisition." Thesis, University of Ulster, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262271.

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37

Russamee, Nilaped. "Development of a high power RF measurement system." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/48483/.

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This research project has developed a high power RF Measurement system in the Centre for High Frequency Engineering, Cardiff University. There are two main contributions of this thesis. The first contribution is the implementation of step attenuators in the RF high power measurement system, incorporated with the approach of using the Sparameter model for correction measured waveform in measurement software processing. The step attenuator is situated between the broadband directional couplers (which obtains the incident and reflected signal from the DUT) and signal receivers (such as a sampling oscilloscope or MTA). The aim of this implementation is to extend the dynamic range of the measurement system and to develop a technique for reducing the recalibration process while the measurement system needs more attenuation in the signal condition part of the measurement system. These benefits allow the quick and convenient characterisation of the DUT under large signal excited environment. The second contribution is the further development of the Harmonic Bypass Structure (HBS), which is used instead of the step attenuator. The advantage of a HBS is that it can overcome the harmonic distortion drawback of the step attenuator approach. This drawback is caused by choosing improper high attenuation which is unsuitable for the measured signal condition. There is, therefore, a trade-off between the fundamental and harmonic frequencies. The advantage of an HBS is that it is capable of selecting the frequency band to attenuate while other frequencies can pass through to the receiver. In the meantime, the S-parameter model and modified measurement software are well suited similar to the step attenuator approach.
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38

Walter, Patrick L. "OPTIMIZING FLIGHT SHOCK AND VIBRATION MEASUREMENT BY RF LINKS." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609222.

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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
Acquiring shock and vibration data from flight vehicles through rf telemetry links has numerous associated challenges. Yet, these measurements are important to establish environmental specifications to provide a basis for system or component design and testing. The principal limitation in acquiring these measurements is the frequency bandwidth available for data transmission. This limited bandwidth is often responsible for invalid data being accepted as valid. This work provides a brief review of time and frequency division multiplexing to identify the potential error contributors to shock and vibration measurements. Its focus is on the design of acceleration measurement systems to eliminate these errors and optimize individual measurement channel performance.
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39

Azhar, Ahsan. "Large Signal RF Measurement Systems and Implementation of a Tuned Receiver System." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-3102.

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This report shows a survey of sate of the art different large signal RF measurement systems. Such measurement systems are discussed in detail with respect to their architecture, method of measurement, calibration, accuracy, dynamic range and bandwidth. Finally, a RF measurement system for large signal was designed and implemented. This measurement system was based on a tuned receiver. Harmonic distortion type measurements were taken by this system and time domain waveforms were reconstructed using external software.

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40

Doo, Seok Joo. "New Pulsed-IV Pulsed-RF Measurement Techniques For Characterizing Power FETs For Pulsed-RF Power Amplifier Design." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211981949.

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41

Holmgren, Erik. "UWB Measurement Techniques and RF Coexistence in a Mobile Handset." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-97082.

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There are two typical interference problems in a multi-radio platform, i.e. blocking due to the saturation of the front end of a receiver by the high power radiation from another transmitter, and desensitization of the receiver by the in-band noise generated by the other transmitter. The UWB device is not an exception. In the coexistence study, two different development kits containing a UWB radio are investigated. The UWB devices cause a raised noise floor and generate severe spurious emissions into the receiver bands for GSM, UMTS, Bluetooth and 802.11b. Consequently this results in degradation of the sensitivity performance of these receivers. Based on measurements performed, the solution for this problem was found by inserting a band-pass filter or a high-pass filter at the transmit path of the UWB device.
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42

Ji, Jie. "Investigation of Skew on Differential High Speed Links." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-722.

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Skew in telecommunication normally means the difference in arrival time of bits transmitted at the same time in differential transmission. As an increasing of transmission data bit rate and more importantly, a data and clock signal rise time of become faster, digital system interconnects became behaving as transmission line. The high speed signals become microwave in nature. The problem is that modern digital designs and verifications require knowledge that has formerly not been needed for a data bit rate of below than 100Mbit but also at the higher frequency range as 5 to 15GHz, however, most references on the necessary subjects are too abstract to be immediately applicable to the skew. For this reason a new method to investigate the skew were introduced, and with which, test board were measured. Since the test boards are made in devise material, and lines on the boards are configured out in distinct structures. In this paper, several methods were applied to find out the skew, and by comparing the results, it could be found that how factors affect the skew, not only the material factor, but some manufactory reason.

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43

Myers, M. Parker (Marion Parker). "Improving production testing of RF products in a noisy measurement environment." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10942.

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Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (leaf 60).
by M. Parker Myers.
M.S.
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44

Ko, Youngseo. "Nonlinear Device Measurement, Characterization, and Modeling for High Power RF Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1371392163.

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45

Autio, E. (Elina). "RF power amplifier design optimization using measurement data and statistical methods." Master's thesis, University of Oulu, 2019. http://jultika.oulu.fi/Record/nbnfioulu-201911163093.

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Abstract. Constantly growing number of mobile data users, and thus the mobile data, creates challenges for spectral efficient data transmission. A high data throughput of a base station requires linear modulation methods and broadband signals. Radio frequency (RF) power amplifier (PA) as a part of base station has an important role making the output signal of the transceiver as linear and spectral efficient as possible. The key RF parameters such as peak power, efficiency, linearity and gain suffer from productional variety which needs to be taken into account in design process. In this thesis, the RF PA design is optimized to tolerate the productional variety of certain RF parameters. The effects of productional variety are pre-analyzed by building the design using corner sample transistors. The build consists of seven different PA module versions where the RF transistor’s internal matchings are modified. The best information of the PA performance is gathered from measurement results and therefore, the presented design optimization method is based on hardware measuring and tuning. Measurement results are compared to self-defined specification limits of each RF parameter and to the nominal version. Another method for analyzing a build which aims for illustrating large population of PA modules is statistical analysis. Along with the help of process capability index Cpk, the statistical behavior compared to the specification limits is evaluated. Peak power proved to be the optimized parameter. Changing the biasing of the transistor and tuning the external input matching network, the peak power results increased. The measurement results proved that the RF PA design is optimized to tolerate the productional variety better with the design optimization method presented in this thesis.RF-tehovahvistinsuunnittelun optimointi mittausdataa ja tilastollisia menetelmiä käyttäen. Tiivistelmä. Mobiilidatan käyttäjien, ja siten myös mobiilidatan määrä on jatkuvasti kasvussa, mikä luo haasteita spektritehokkaaseen datansiirtoon. Tukiaseman suuri datansyöttö vaatii laajakaistaisia signaaleja sekä lineaarisia modulointimenetelmiä. RF-tehovahvistimella on siis tärkeä rooli tukiaseman osana saada lähtösignaalista mahdollisimman lineaarinen ja spektritehokas. Tehovahvistimen RF-parametrit, kuten huipputeho, hyötysuhde, lineaarisuus sekä vahvistus kärsivät tuotannollisesta vaihtelusta, kun tehovahvistinmoduulia aletaan tuottaa suuria määriä. Tämän opinnäytetyön tarkoituksena on optimoida RF-tehovahvistimen suunnittelu sellaiseksi, että se on sietokykyinen tiettyjen RF-parametrien tuotannolliselle vaihtelulle. Tuotannollisen vaihtelun vaikutuksia analysoidaan etukäteen käyttämällä tehovahvistimessa kulmanäytetransistoria. Kulmanäytteet koostuvat seitsemästä erilaisesta versiosta, jossa RF-transistorin sisäisiä sovituksia on muunneltu. Paras tieto tehovahvistimen käyttäytymisestä saadaan mittaustuloksista, minkä takia työssä käytetään mittauksiin ja laitteiston hienosäätämiseen perustuvaa optimointimetodia. Kulmanäytteiden mittaustuloksia verrataan itse määrittelemiin RF-parametrien spesifikaatioihin sekä nominaaliversioon. Toinen analyysimetodi suuren tehovahvistinmoduulimäärän havainnollistamiseen on tilastollinen analyysi. Prosessin kyvykkyysindeksin Cpk analysoinnin kanssa, RF-parametrien tilastollinen käyttäytyminen spesifikaatiorajoihin verrattuna voidaan arvioida. Huipputeho osoittautui optimoitavaksi parametriksi. Transistorin biasoinnin muutoksella sekä tulon ulkoisen sovituspiirin muokkauksella huipputehoa saatiin kasvatettua. Mittaustulokset osoittavat, että työssä esitetyllä suunnittelun optimointimetodilla tehovahvistin saatiin sietämään tuotannollista vaihtelua paremmin.
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46

Sriramagiri, Harsha. "B Spline Modelling of Non Linear Power Amplifiers based on LSNA measurememts." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243536474.

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47

Lei, Feiran. "Injection Locked Synchronous Oscillators (SOs) and Reference Injected Phase-Locke Loops (PLL-RIs)." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492789278258943.

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48

Acimovic, Igor. "Contributions to the Design of RF Power Amplifiers." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24406.

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In this thesis we introduce a two-way Doherty amplifier architecture with multiple feedbacks for digital predistortion based on impedance-inverting directional coupler (transcoupler). The tunable two-way Doherty amplifier with a tuned circulator-based impedance inverter is presented. Compact N-way Doherty architectures that subsume impedance inverter and offset line functionality into output matching networks are derived. Comprehensive N-way Doherty amplifier design and analysis techniques based on load-pull characterization of active devices and impedance modulation effects are developed. These techniques were then applied to the design of a two-way Doherty amplifier and a three-way Doherty amplifier which were manufactured and their performance measured and compared to the amplifier performance specifications and simulated results.
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49

Lee, Jun Seok. "On-Wafer Characterization of Electromagnetic Properties of Thin-Film RF Materials." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1308311479.

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50

Newhall, William George. "Wideband Propagation Measurement Results, Simulation Models, and Processing Techniques for a Sliding Correlator Measurement System." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35678.

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Radio wave propagation measurements provide a way to accurately and reliably characterize environments to assist in the development and optimization of wireless communication systems. As digital radio systems occupy wider bandwidths and use multipath signal combining to enhance quality of service, knowledge of time dispersion and the multipath structure of radio channels become increasingly important. The wideband measurement system presented herein provides a practical means to precisely measure the delays and strengths of individual multipath components which arrive at a radio receiver.

Presented in this Thesis are fundamental theory, practical implementation, and simulation models for a sliding correlator measurement system. The sliding correlator technique is explained in detail and large-scale measurement survey is presented. Techniques for statistically quantifying the characteristics of propagation using the sliding correlator measurements are presented and compared. The development of simulations of the sliding correlator system is described, and simulation results are used to test conventional and newly developed post-processing algorithms.

This Thesis presents a practical view of the sliding correlator measurement system, but its foundations are rooted in the theoretical results which are explained and derived herein. Propagation researchers and students in the wireless communication field may find this work and the cited references useful for continued study of wideband propagation measurements or for application of the sliding correlator system as a wideband measurement solution.
Master of Science

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