TEORIA ELECTROMAGNETICA Y ONDAS PASO 2: RECONOCE LAS APLICACIONES ELECTRODINÁMICA Y DE ONDAS
PRESENTADO POR: JOSE LUIS CASTRO LAVERDE CODIGO: 1083908247 ANDREA DEL PILAR HERRERA SANDOVAL
TUTOR WILMER HERNAN GUTIERREZ GRUPO 13
UNIVERSIDAD NACIONAL ABIERTA Y A DISTANCIA (UNAD) TEORIA ELECTROMAGNETICA Y ONDAS MARZO 2018
INTRODUCTION
In this work we find a study of the concepts corresponding to the means of propagation that use the waves from which they are emitted until they reach a receiver or are lost in the medium that they apply, this work will apply that theme already in problems that We can find in real environments given that we will calculate the tangent of losses or what we know as signal loss, we will also learn the different frequencies that apply in each of the different drivers and their application, knowing how to calculate by means of formulas that give us the frequency and distance of propagation from x frequency it is necessary to emphasize that this issue will be of great importance in our professional training given that it is applied permanently nowadays.
OBJECTIVES
Develop the skills to apply the best solution to each problem, based on the knowledge initially studied. Analyze the way to know the loss suffered by a frequency signal from the tangent of loss. Develop the skills to apply the knowledge corresponding to electrodynamics and waves through problems raised.
ACTIVITIES TO DEVELOP
1. Explain the practical application of the loss tangent with an example. It is called loss tangent to the relationship established between current and displacement and corresponds to the angle that is formed in this relationship, this measure is used to represent the quality of isolation of a medium. The following statuses are taken as reference for said calculation, as previously established. Example: Calculate the loss tangent of dry soil at a frequency of 100 MGHZ
Development: For dry soil we take the data from the table for incongnitas ∈
= 1,000 − ∈ = 3
Clearing the angle we obtain:
2. What kind of information give us the propagation velocity in electromagnetic waves propagation? This variable what it does is the measurement of the time that a wave needs so that in the same point of the space the crossing by "0" or level of maximum signal appears. This depends exclusively on the electromagnetic properties of the medium in which it propagates. 3. Explain how an electromagnetic wave behaves in free space, perfect dielectrics and good conductors. free space: Electromagnetic waves in free space
can travel at the speed of light. However, in the atmosphere there are losses in the signal that are not found in the vacuum. Radio waves are considered electromagnetic waves like light and, like it, travel through free space in a straight line with a speed of 300000000 meters per second. perfect dielectrics: the
treatment of the propagation of electromagnetic waves is similar to what is said in free space, since the latter is a perfect dielectric medium. The only difference lies in the fact that the perfect dielectric media have a permitivity different from that of the vacuum, a fact that must be taken into account since it affects the propagation of the waves, varying the phase speed, characteristic impedance of the medium, refractive index, etc., with respect to the values obtained for the vacuum. good conductors: When
an electromagnetic wave propagates, not in a vacuum, but in any material medium, the speed of propagation is not the same, in addition to other important phenomena that should be studied, such as dispersion, reflection, refraction and absorption.
4. Using the electromagnetic spectrum, explain the practical application of every type of radiation.
5. What is the refraction index and what kind of information give us about the electromagnetic waves behavior? It informs us the relationship that exists between the speed of light in empty space and the phase velocity of a signal in a specific medium. This variable will always be a value greater than or equal to 1. Some examples of refractive indices
6. are is a plane wave and a plane not and where used? what is a magnetic and non-magnetic means and where are used? why use flat waves to explain practical models associated with electromagnetic phenomena? a plane wave are those waves propagating in one direction along the space. A magnetic medium is a device that stores information by means of magnetic Hard Disks or disk drives, disk rigid waves. It is an example of electromagnetic waves, which sends audio signals.
In group solve the following practical exercise
1.In an excel document make the following actions: In a sheet put the following table, assigning an average frequency for every type of radiation. Acronym
Meaning
Selected frequency
ELF
Extra Low Frequency
SLF ULF VLF LF MF HF VHF
Super Low Frequency Ultra Low Frequency Very Low Frequency Low Frequency Medium Frequency High Frequency Very High Frequency
UHF SHF EHF
Ultra High Frequency Super High Frequency Extra High Frequency
entre los 30 y los 300 Hz 30 Hz a 300 Hz 300Hz a 3KHz 3KHz a 30KHz 30KHz a 300KHz 300KHz a 3MHz 3MHz a 30MHz 30MHz a 300MHz 300MHz a 3GHz 3GHz a 30GHz 30GHz a 300GHz
Choose one of the following problems, solve it and share the solution in the forum. Perform a critical analysis on the group members’ contributions and reply this in the forum.
5..For a 2.5GHz signal, traveling in seawater find the attenuation per length unit. How long does the signal have to travel, in order to have an attenuation greater than 3dB? The extra water can be considered a good conductor, therefore we use that assumption to solve. The attenuation constant is given by:
= √ ..µ. For seawater, the parameters are:
= 2.5 µ=1 =4
Knowing this we substitute and solve: having:
= 198.691/ That would be the attenuation count, under these conditions. Now perhaps you ask is how much the wave travels for an attenuation of 3dB, which equals half of its power:
1 2 − = 2 =
1 = ∗ ln(2) = 1.51
CONCLUSIONS
We develop the ability to analyze the behavior of a signal from the subject studied for this first phase of the course corresponding to the subject of electrodynamics and waves, which allows us to study the waves from the frequencies with which they are emitted and know characteristics like the tangent of losses. In addition to this we analyze the different methods of solving the problems raised from the formulas of the equations given to us
BIBLIOGRAPHIC REFERENCES
Gutiérrez, W. (2017). Loss http://hdl.handle.net/10596/13139
Tangent
[Video].
Retrieved
from
Chen, W. (2005). The Electrical Engineering Handbook. Boston: Academic Press. 513-519. Retrieved from http://bibliotecavirtual.unad.edu.co:2048/login?url=http://search.ebscohost.com/login.aspx? direct=true&db=nlebk&AN=117152&lang=es&site=ehost-live&ebv=EB&ppid=pp_513 Quesada-Pe ́rez, M., & Maroto-Centeno, J. A. (2014). From Maxwell's Equations to Free and Guided Electromagnetic Waves: An Introduction for First-year Undergraduates. New York: Nova Science Publishers, Inc, 49-80 Retrieved from http://bibliotecavirtual.unad.edu.co:2051/login.aspx?direct=true&db=nlebk&AN=746851& lang=es&site=eds-live&ebv=EB&ppid=pp_49
