3_Waveguide Based Devices
Transcript of 3_Waveguide Based Devices
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The waveguide components generallyencountered are:
Tee junctions
E-plane, H-plane &Magic Tee
Attenuators
Directional couplers Waveguide terminating devices
Slotted sections
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Components that reduce the amount of power a fixedamount, a variable amount or in a series of fixed stepsfrom the input to the output of the device.
Operate on the principle of interfering with the electricfield or magnetic field or both.Slide vane attenuators: a resistive material placed in
parallel with the E-lines of a field current will induce acurrent in the material that will result in I2Rpower loss.
Flap attenuator: has a vane that is dropped into thewaveguide through a slot in the top of the guide. Thefurther the vane is inserted into the waveguide, thegreater the attenuation.
Rotary vane attenuator: It is a precision waveguide
attenuator & attenuation is independent on frequency.
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provides a termination designed to absorb allthe incident power with very little reflection,
effectively terminating the line or port in itscharacteristic impedance.
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Waveguide Tees
Cutting arectangular slotalong the width
of the mainwaveguide &attachinganother
waveguide
H-plane Tee
Main arm
H-arm /side arm
Port 3
Port
1
Port 2
Collinear ports
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Axis of the side arm is parallel to the plane ofthe main TL
All the 3 arms lies in the plane of magnetic fieldmagnetic field divides itself into the armsCURRENT JUNCTION
When TE10
mode is allowed to propagate intoport 3, the electric fields do not change theirdirection when coming out of port 1 & 2 Hplane tee
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S-matrix of H-plane Tee
S13 = S23 due to plane ofsymmetry at the junction
Symmetric propertyS12 = S21S23 = S32 = S13S13 = S31 Perfect match at the junction
S33 = 0
333231
232221
131211
SSS
SSS
SSS
S
01313
132212
131211
SS
SSS
SSS
S
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Unitary property [S] [S] * = [ I ]
100
010
001
0**
***
***
0 1313
132212
131211
1313
132212
131211
SS
SSS
SSS
SS
SSS
SSS
21)(
11
1***)(
213
222
21222
213
212
211
13131212111111
SSSCR
SSS
SSSSSSCRfrom (1) & (2)|S11|
2 = |S22|2
S11 = S22 (3)
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52
1,12
41)(
13
2
13
213
21333
SS
SSCR
70**
0
0**
60**)(
1211
1211
13
121113
1213111313
SS
SS
S
SSS
SSSSCR
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Using (3,5,7) in (1)
92
1
82
1
2
12
12
1
12
11
2
11
2
11
2
11
S
S
S
SS
102
122 S
02
1
2
12
1
2
1
2
12
1
2
1
2
1
S
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3
2
1
3
2
1
02
1
2
121
21
21
2
1
2
1
2
1
a
a
a
b
b
b
aSb
213
3212
3211
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
aab
aaab
aaab
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0
2
2
0,0,0)1(
3
32
31
213
b
ab
ab
aaaa3 power input at port 3
Power gets equally divided
b/n the ports (1) & (2)
P3 = P1+P2=2 P1=2P2Amount of power coming out of port 1 or 2 due to i/p at port 3
dBP
P
P
P3
2
1log10log10log10
3
2
3
1 3 dB Power splitter
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2222
0222
0222
0,)2(
213
3212
3211
321
aaaab
aaab
aaab
aaaa
Power output at port 3 is
addition of power inputs from(1) & (2) in phaseH arm is
also called SUM ARM
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Waveguide Tees
Cutting arectangular slotalong the
broaderdimension ofthe main
waveguide &attachinganother
waveguide
E-plane Tee
H-arm /side arm
Main arm
Port3
Port
1
Port 2
Collinear ports
Port 1
Port 2
Collinear ports
Port 3E arm
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S-matrix of E-plane Tee
S13 = -S23 due to plane ofsymmetry at the junction & o/p
180
out of phase Symmetric property
S12 = S21S23 = S32 = -S13S13 = S31 Perfect match at the junctionS33 = 0
333231
232221
131211
SSS
SSS
SSS
S
01313
132212
131211
SS
SSS
SSS
S
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Unitary property [S] [S] * = [ I ]
100
010
001
0**
***
***
0 1313
132212
131211
1313
132212
131211
SS
SSS
SSS
SS
SSS
SSS
21)(
11
1***)(
213
222
21222
213
212
211
13131212111111
SSSCR
SSS
SSSSSSCRfrom (1) & (2)|S11|
2 = |S22|2
S11 = S22 (3)
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52
1,12
41)(
13
2
13
213
21333
SS
SSCR
7
0
0**
60**)(
221211
13
121113
1213111313
SSS
S
SSS
SSSSCR
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Using (3,5,7) in (1)
92
1
82
1
2
12
12
1
12
11
211
2
11
2
11
S
S
S
SS
102
122 S
02
1
2
12
1
2
1
2
12
1
2
1
2
1
S
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3
2
1
3
2
1
02
1
2
121
21
21
2
1
2
1
2
1
a
a
a
b
b
b
aSb
213
3212
3211
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
aab
aaab
aaab
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0
2
2
0,0,0)1(
3
32
31
213
b
ab
ab
aaaa3 power input at port 3
Power gets equally divided
b/n the ports (1) & (2) with a
phase difference of 180E plane tee 3 dBPower splitter
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0
22
22
0,)2(
3
2
1
321
b
aab
aab
aaaa
Power output atport 3 is zero with
equal inputs at
port 1 & 2
2
2
2
0,0,0)3(
13
12
11
321
ab
ab
ab
aaa
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H-arm
E-arm
Port1
Port2
Port3
Port4
00
00
1414
131314132212
14131211
SS
SS
SSSS
SSSS
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H-plane Tee section S23 = S13 E-plane section S24 = -S14 Geometry of the section S34 = S43 = 0
Symmetric propertyS12 = S21S23 = S32S13 = S31S
24
= S42S43 = S34
S14 = S41 Port 3 & 4 matched S33 = S44 = 0
00
00
1414
1313
14132212
14131211
SS
SS
SSSS
SSSS
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1000
0100
0010
0001
00**
00**
****
****
00
00
1414
1313
14132212
14131211
1414
1313
14132212
14131211
SS
SS
SSSS
SSSS
SS
SS
SSSS
SSSS
3
21)(
11)(
2211
2
14
2
13
2
22
2
1222
214
213
212
21111
SS
SSSSCR
SSSSCR
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80
0
121
21
1211
2
12
2
11
212211
SS
SS
SS
Using (3,5,7) in (1)
52
1
41)(
13
213
21333
S
SSCR
721
61)(
14
214
21444
S
SSCR
002
1
2
1
002
1
2
12
1
2
100
2
1
2
100
S
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Four port waveguide junctionPrimary waveguide 1-2Secondary waveguide 3-4
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With matched terminations at all the ports, propertiesof ideal DC
1. Portion of power travelling from port 1 to port 2 is
coupled to port 4 not to port 3.2. Portion of power travelling from port 2 to port 1 iscoupled to port 3 not to port 4.
3. Portion of power incident at port 3 is coupled toport 2 but not to port 1
4. Portion of power incident at port 4 is coupled toport 1 but not to port 2
5. Ports 1 &2 are decoupled as are ports 2&4
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Coupling Factor C Directivity D Isolation I
dBP
PD
b
f
10log10
Piincident power at port1Prreceived power at port2Pfforward coupled power at port4
Pbback power at port3
dBP
PI
b
i
10log10
dBP
PC
f
i
10log10
)()()( dBDdBCdBI
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All ports are perfectly matched S12 =S22 = S33 =S44 =0 Symmetric property
S23 = S32, S13 = S31,S24 = S42,S43 = S34,S14 = S41 No coupling b/n port 1 & 3 S13 = S31 = 0 No coupling b/n port 2 & 4 S24 = S42 = 0
00
0000
00
3414
3423
2312
1412
SS
SSSS
SS
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1000
0100
0010
0001
0*0*
*0*0
0*0*
*0*0
00
00
00
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2314
3423
2312
1412
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3423
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SS
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SS
SS
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321)(
11)(
2314
21321222
214
21211
SS
SSCR
SSCR
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1234
234
214
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1)3(
41)(
SS
SS
SSCR
from
343412
12
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*SPSS
PS
S
ve&realasAssume
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jySjyS
SSPSSP
PSPS
SSSSCR
2323
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*,
0*,00*
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QP
jQSS
PSS
SjQSLet
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