lecture viii antennas & propagation -1- antennas & propagation mischa dohler king’s...
TRANSCRIPT
Lect
ure
VII
I
Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
Pro
paga
tion
-1-
Antennas
&
Propagation
Mischa DohlerMischa Dohler
King’s College LondonKing’s College London
Centre for Telecommunications ResearchCentre for Telecommunications Research
Lect
ure
VII
I
Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
Pro
paga
tion
-2-
Books for Propagation
- Simon Saunders Simon Saunders “Antennas & Propagation”“Antennas & Propagation”
- William Jakes William Jakes “Microwave Mobile “Microwave Mobile
Communications”Communications”
- Kaveh Pahlavan Kaveh Pahlavan “Wireless Information “Wireless Information
Networks”Networks”
- try to omit articles and books from: try to omit articles and books from:
Lect
ure
VII
I
Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
Pro
paga
tion
-3-
Overview of Lecture VIII
- ScenariosScenarios
- Propagation MechanismsPropagation Mechanisms
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
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&
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paga
tion
-4- Propagation Scenarios
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-5-
Satellite
Mega Cells
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-6-
Outdoor-Outdoor
Macro, Micro and Umbrella Cells
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-7-
Outdoor-Indoor
Macro and Micro Cells
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-8-
Indoor-Indoor
Micro and Pico Cells
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
Pro
paga
tion
-9-
Losses and Deterioration
Propagation Mechanisms:
(1) Free Space Propagation
(2) Reflection and Transmission
(3) Scattering
(4) Diffraction
Distortions:
(5) Multipath Propagation
(6) Doppler Effect
Propagation Conditions:
(a) Line of Sight (LOS)
(b) non Line of Sight (nLOS)
(c) obstructed Line of Sight (oLOS)
Lect
ure
VII
I
Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
Pro
paga
tion
-10- Propagation Mechanisms
Lect
ure
VII
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Ant
enna
s &
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ropa
gatio
nA
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nas
&
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paga
tion
-11-
Free Space Propagation
Frii’s Transmission Formula:
Variations with Distance d:
The dB mysticism:
‘Loss’ Myth:
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-12-
Reflection and Transmission
TE and TM waves
Snell’s Law:
Fresnel Coefficients:
‘Object Size’ Myth:
Lect
ure
VII
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Ant
enna
s &
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ropa
gatio
nA
nten
nas
&
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paga
tion
-13-
Reflection and Transmission
Reflection: TE and TM waves
Transmission: TE and TM waves
Lect
ure
VII
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Ant
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s &
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gatio
nA
nten
nas
&
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paga
tion
-14-
Reflection and Transmission
Circular Elliptical After Reflection or
Transmission of non-linear
polarisation we always
obtain elliptical
polarisation.
Elliptical Elliptical
Linear Linear
i < Brewster i > Brewster
Left Right
Right Left
Left Left
Right Right
Change of Polarisation
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
nten
nas
&
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paga
tion
-15-
Scattering
Smooth Rough Rougher
Fraunhofer Criterion for
smooth surfaces
Rayleigh Criterion for
smooth surfaces
Lect
ure
VII
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Ant
enna
s &
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ropa
gatio
nA
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nas
&
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paga
tion
-16-
Scattering
Correlation Function
Correlation Length
Correlation Height
Roughness Factor
Lect
ure
VII
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Ant
enna
s &
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gatio
nA
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nas
&
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paga
tion
-17-
Diffraction
Huygen's Principle
‘Sharp Edges’ Myth
Consequences of Diffraction
Field-Strength in
shadowed areas
Rapid Field-strength
fluctuations
Lect
ure
VII
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Ant
enna
s &
P
ropa
gatio
nA
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nas
&
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paga
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-18-
Diffraction
Optical and Shadow Region
Lect
ure
VII
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Ant
enna
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gatio
nA
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nas
&
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paga
tion
-19-
Diffraction
Diffraction Coefficient
Lect
ure
VII
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Ant
enna
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gatio
nA
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nas
&
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paga
tion
-20-
Diffraction
Diffraction Coefficient
Lect
ure
VII
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Ant
enna
s &
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ropa
gatio
nA
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nas
&
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paga
tion
-21-
Diffraction
Diffraction Coefficient