PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 7: Start reading Chapter 3
PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 34:
13
1 PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 34: Special Topics in Electrodynamics: Review – Scattering and interference phenomena Course assessment forms 04/23/2014 PHY 712 Spring 2014 -- Lecture 34
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PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 34: Special Topics in Electrodynamics: Review – Scattering and interference phenomena Course assessment forms. r. Review of radiation from antenna. z. q. Linear center-fed antenna. d/2. - PowerPoint PPT Presentation
Transcript of PHY 712 Electrodynamics 10-10:50 AM MWF Olin 107 Plan for Lecture 34:
PHY 712 Spring 2014 -- Lecture 34 1
PHY 712 Electrodynamics10-10:50 AM MWF Olin 107
Plan for Lecture 34:
Special Topics in Electrodynamics:
Review – Scattering and interference phenomena
Course assessment forms
04/23/2014
PHY 712 Spring 2014 -- Lecture 34 204/23/2014
PHY 712 Spring 2014 -- Lecture 34 304/23/2014
PHY 712 Spring 2014 -- Lecture 34 404/23/2014
PHY 712 Spring 2014 -- Lecture 34 504/23/2014
PHY 712 Spring 2014 -- Lecture 34 604/23/2014
Review of radiation from antenna
Linear center-fed antennaz
r
qd/2
ˆ3 '0
0
,
' ',4
',
ˆsin | | ( ) ( )2
ikrik
kdk
ed r e
r
z xI y
r r
A r
J r
r zJ
PHY 712 Spring 2014 -- Lecture 34 704/23/2014
Linear center-fed antenna continued
/1
cos( '0
/2
)0
02
0
, ' 4
cos cos cos2 2
=2 sin
ˆ
sin | ' |2
ˆ
dikrik
d
ikr
zI edz e
r
kd kdI e
r
kdk z
z
z
A r
00
2
22
0
Time averaged power:
cos cos cos1 2 2
= 8 sin
kd kddP
Id
PHY 712 Spring 2014 -- Lecture 34 804/23/2014
Linear center-fed antenna continued
00
2
22
0
Time averaged power:
cos cos cos1 2 2
= 8 sin
kd kddP
Id
2
2 00 2 2
0
00 2 2
0
4
2
cos cos1 2
for = 8 sin
cos cos4 2
for 2
:
= 8 sin
:
dPkd I
d
dPkd I
d
PHY 712 Spring 2014 -- Lecture 34 904/23/2014
00
2
22
0
Time averaged power:
cos cos cos1 2 2
= 8 sin
kd kddP
Id
Linear center-fed antenna continued
Radiation patterns kd=m :p m=1 m=2 m=3
PHY 712 Spring 2014 -- Lecture 34 1004/23/2014
00
2
22
0
Time averaged power:
cos cos cos1 2 2
= 8 sin
kd kddP
Id
Linear center-fed antenna continued
Radiation patterns kd=m :p m=4 m=5 m=6
PHY 712 Spring 2014 -- Lecture 34 1104/23/2014
Antenna arrays
http://www.tennadyne.com/company.htm
z
x
rf
a
PHY 712 Spring 2014 -- Lecture 34 1204/23/2014
Antenna arrays z
x
rf
a
z’’
4 4z
/4 1
cos( )0 0
0/4
( 1) cos( )/20 0
ˆ, cos( )4
sin( cos( ) / 2)ˆ
2 sin( cos( ) / 2
)=
ikr Nikma
m
ikri N ka
I er dz kz e
r
I e Nkae
kr ka
A z
z
1
00
2
ˆ
4 4
, , , cos ( ) ( )N
i t
m
x y z I kz y x ma e
k zc
J z
PHY 712 Spring 2014 -- Lecture 34 1304/23/2014
Antenna arrays ( 1) cos( )/20 0
220 0
2
=
Time averaged power in x-y plane
sin( cos( ) / 2)ˆ,
2 sin( cos( ) / 2)
sin( cos( ) / 2)
8 sin( cos( )
:
)
/ 2
ikri N kaI e Nka
r ekr ka
I Nka
ka
cdP
d
A z
f
N=3 N=12
