23,217 resources related to Attenuation
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AMC2020 is the 16th in a series of biennial international workshops on Advanced Motion Control which aims to bring together researchers from both academia and industry and to promote omnipresent motion control technologies and applications.
The Conference focuses on all aspects of instrumentation and measurement science andtechnology research development and applications. The list of program topics includes but isnot limited to: Measurement Science & Education, Measurement Systems, Measurement DataAcquisition, Measurements of Physical Quantities, and Measurement Applications.
The conference provides an overview of the state of the art developments and innovations in Antennas, Propagation, and Measurements, highlighting the latest requirements for future applications.
The main theme of this conference is microwave measurements. Technical papers are soliciteddescribing original work in the areas of measurementrequirements for new, emerging, and developing technologies including, but not limited to,medical/biological areas, nanomaterials, graphene and related materials, and THz and relatedhigh frequency areas. Topics of particular interest include: Materials measurements foremerging technologies, Measurements in extreme impedance environments, mm-wave/THzand other higher frequency measurement measurements in highly nonlinear environments, deembeddingand correction methods for complex interfaces/fixtures, and all areas of RF,microwave and/or millimeter wave measurement.
The scope of the conference is the presentation of the latest development in the area ofmicrowave circuits and systems, antenna design and modelling, communication systems,microwave circuits and systems, signal propagation, EMC and related disciplines.
Experimental and theoretical advances in antennas including design and development, and in the propagation of electromagnetic waves including scattering, diffraction and interaction with continuous media; and applications pertinent to antennas and propagation, such as remote sensing, applied optics, and millimeter and submillimeter wave techniques.
The theory, design and application of Control Systems. It shall encompass components, and the integration of these components, as are necessary for the construction of such systems. The word `systems' as used herein shall be interpreted to include physical, biological, organizational and other entities and combinations thereof, which can be represented through a mathematical symbolism. The Field of Interest: shall ...
Broad coverage of concepts and methods of the physical and engineering sciences applied in biology and medicine, ranging from formalized mathematical theory through experimental science and technological development to practical clinical applications.
Broadcast technology, including devices, equipment, techniques, and systems related to broadcast technology, including the production, distribution, transmission, and propagation aspects.
Part I will now contain regular papers focusing on all matters related to fundamental theory, applications, analog and digital signal processing. Part II will report on the latest significant results across all of these topic areas.
Radio Science, 2007
A key parameter of the statistics of the rate of change of rain attenuation (“fade slope”) on satellite links is the variance of relative fade slope. This paper shows how this parameter can be derived from rain rate measurements without the use of satellite beacon measurements. Relating rain rate directly to attenuation would give unrealistic results. A theoretical model to ...
Radio Science, 2011
A technique for the estimation of total liquid water content (LWC; the sum of cloud water and rainwater contents) using simultaneous S and Kaband scanning radar observations is proposed and tested using the National Center for Atmospheric Research simultaneous S band and Kaband dual-polarimetric (S-PolKa) radar system. The sources of error for this wavelength pair are evaluated, and the methods ...
Radio Science, 1984
No abstract is available.
1984 International Symposium on Electromagnetic Compatibility, 1984
Radio Science, 2014
This contribution presents a model to generate time series of rain attenuation by adapting a large set of rain attenuation measurements to different locations. The proposed model allows generating rainy and not rainy conditions for multiple stations in a large geographical area, reproducing the actual spatial and temporal variability of the rain process, with limited computational effort. Single site and ...
A key parameter of the statistics of the rate of change of rain attenuation (“fade slope”) on satellite links is the variance of relative fade slope. This paper shows how this parameter can be derived from rain rate measurements without the use of satellite beacon measurements. Relating rain rate directly to attenuation would give unrealistic results. A theoretical model to estimate the variance of relative fade slope is derived, using the integrating effect of rain rate variations along the propagation path and using as inputs several meteorological parameters only. The theoretical values are compared to measured results from a link in the United Kingdom at 50 GHz. The agreement is good on average and also in their correlation with the type of rain and with the rain height. With the wind speed, the theoretical values increase more strongly than the measured results, which may be due to the limited spatial resolution of the meteorological data.
A technique for the estimation of total liquid water content (LWC; the sum of cloud water and rainwater contents) using simultaneous S and Kaband scanning radar observations is proposed and tested using the National Center for Atmospheric Research simultaneous S band and Kaband dual-polarimetric (S-PolKa) radar system. The sources of error for this wavelength pair are evaluated, and the methods to mitigate them are discussed. The results are LWC estimates at each radar volume that are equivalent to specifying a reflectivity (Z) – LWC relation constrained by the measured attenuation over 2 km radar ray segments. Because the radars are scanning, the LWC can be mapped out over the spatial volume and temporal evolution of the clouds. The method produces reasonable results that qualitatively compare well to in situ aircraft observations.
No abstract is available.
This contribution presents a model to generate time series of rain attenuation by adapting a large set of rain attenuation measurements to different locations. The proposed model allows generating rainy and not rainy conditions for multiple stations in a large geographical area, reproducing the actual spatial and temporal variability of the rain process, with limited computational effort. Single site and joint statistics of rain attenuation obtained by the time series of measurements are discussed. The model is used to show the effectiveness, in terms of link margin, of gateway networks in smart diversity arrangement, for different separation distances among sites.
For a class of nonlinear systems with missing measurements and multiple disturbances, Disturbance attenuation and rejection problems are investigated in this paper. The state observer and disturbance observer are constructed based on measurement output error and/or control input. The measurement output may occur to loss in the real systems, which are characterized by stochastic binary sequence. Two types of disturbances are also considered, one is emerged from H2form, which are attenuated by H∞control. The other is rejected by disturbance-observer-control. The pth(1, 2) moment exponential stability are analyzed in terms of linear matrix inequalities (LMIs) for the systems with known nonlinear dynamics. Simulation examples are provided to demonstrate the effectiveness of the results.
A large, one dimensional receiving array has been developed in the attenuation projection measurement and the phase insensitive (PIS) data processing method has been used in the evaluation. Our aim of this study is to suppress the corresponding artifacts in the attenuation projection. Four different cylindrical, biomaterial objects are tested in the measurement. The results are compared with phase sensitive (PS) results. The conclusion is given in the last part.
A possibility of a significant increase in the electronic efficiency of TWTs is considered in this paper. The output power and the power at the attenuator of a two-section TWT are measured, simulated, and calculated analytically at a fixed frequency for different distances between the attenuator and the output terminal. The significant difference between the output power and power at the attenuator's input is explained by the e-beam intensive interaction with the wave in the absorbing section. Attenuators with decreased interaction impedance are offered to increase the TWT's electronic efficiency.
Building up a ground loop is a very common mistake when validating anechoic rooms below 30 MHz, because this is not an issue in the frequency ranges above. It is required to measure a Site Attenuation of nearly 120 dB, but a ground loop can limit this to 63.1 dB. So a large systematic error will occur. There are several possibilities to avoid a ground loop by using battery powered devices, an isolation transformer or an RF transformer. Special care has to be taken to recognize all ground loops which can be formed by communication cables and reference frequency links. Also, a ground loop can be formed by the installed cables which are routed below the ground plane.
It is a well-known fact that the attenuation region of the traveling-wave tube is very important to the performance of the tube, particularly with respect to gain and efficiency of the tube which is relatively short in terms of wavelengths. Characteristics of the attenuator in the passive tube have been measured frequently and variations of attenuation and wave velocity with respect to frequency and thickness of coating are known. In the interests of trying to understand the effect of the attenuator on efficiency, we have attempted to make certain calculations of performance of a theoretical attenuator such as is frequently used on certain spirals and the results of such calculations are presented here.
This project provides recommended practices for the prediction and practical determination of safe distances from radio and radar transmitting antennas when using electric initiators to remotely detonate an explosive charge. Specifically, this document includes mathematical formulas, tables, and charts that allow the user to determine safe distances from RF transmitters with spectrum bands from 0.5 MHz to 300 GHz, including ...
To specify protocols for the measurement of the peak spatial-average specific absorption rate (SAR) in a simplified model of the head of users of hand-held radio transceivers used for personal wireless communications services and intended to be operated while held next to the ear. It applies to contemporary and future devices with the same or similar operational characteristics as contemporary ...
This recommended practice provides a standardized body of theory, techniques, and procedures for measuring the spectral characteristics of 8-VSB transmitters used for terrestrial transmission of digital television (DTV) in the frequency range near their assigned channels. Essential characteristics are specified and measurement procedures are given that ensure that all parties will obtain comparable results. The theory and techniques presented are ...
Revise and develop specifications for preferred methods for measuring and computing external radiofrequency electromagnetic fields to which persons may be exposed. In addition, the document will specify preferred methods for the measurement and computation of the resulting fields and currents that are induced in bodies of humans exposed to these fields over the frequency range of 100 kHz to 300 ...