Waveguide Technology
“ Waveguide Subsystems for Antenna Feed“
Angel Mediavilla Sánchez*, Francisco Marante Rizo**, Karen Cepero**
* Departamento de Ingeniería de Comunicaciones
Escuela Técnica Superior de Ingenieros de Telecomunicación
Universidad de Cantabria (UNICAN) – España
** Departamento de Telecomunicaciones
Instituto Superior Técnico José Antonio Echeverría (ISPJAE)
La Habana - Cuba
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Where are we ?
Power Amplifier
or
Low Noise Amplifier
BRNO- march 2011
Antenna
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
GENERALITIES
RADIOASTRONOMY
MULTIPLE FEED
RADAR
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
GENERALITIES
Bricolage also WORKS
Short
N type Connector
BRNO- march 2011
Circular Waveguide
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
“Planar” Transmission Lines
w >> b
Strip
Parallel Plate
Pure TEM mode
no dispersion
b
εr
w
µstrip
εr
Important dispersion
Radiation Losses
closed µstrip
Propagate
Propagate
TEMor
or
TEM
quasi-TEM
quasi-TEM
εr
No radiation Losses
Waveguide modes could appear
suspended µstrip
suspended Strip with Vias
εr
εr
Small Losses
In the dielectric
BRNO- march 2011
No dielectric Losses
No dispersion
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
“Coaxial” Transmission Lines”
dielectric εr
Rext=b
Rint=a
0.5.Ln(b/a)
Zo==60.(
60.(µµr/r/εεr)r)0.5
Zo
.Ln(b/a)
vp = c / (µr.εr)0.5
TEM mode
Attenuation in dB/m:
λ = λo.(vp/c)
0.5
general: λλgg==λλoo/ /(ε
(εr)r)0.5
general:
α = αc + αd
0.5
b/a]
δδss. .(ε(εr)r)0.5. .[1[1++b/a]
13.6 ----------------------------------------------------------ααcc==13.6
Ln(b/a)
λλoo. .bb. .Ln(b/a)
(εr)r)0.5. .tan
tanδδ
(ε
27.3 ----------------------------------ααdd==27.3
0.5
λλoo
in db/m
- δs : Skin effect
- tanδ : dielectric
Both values increase with Frequency
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
LINEAS DE TRANSMISION “COAXIAL”
If we Increase the transmission
frequency
TEM mode
TEM mode
0
SUPERIOR modes
TE11 mode
Freq
Fc TE11
Fc TEnm
Nearest superior mode : TE11
Pout
cc
(forb/a
b/a<<7)
7) approximate
approximate λλcc==ππ.(a+b)
.(a+b) Fc
Fc== --------------------------------------------------(for
0.5
(a+b)(µ
(µr.r.εεr)r)0.5
ππ(a+b)
Example : SMA connector 2b=4.1mm 2a=1.26mm Er=2.0
Zc=50ohm
Fc (TE11) = 25 GHz
BRNO- march 2011
Fmax
Freq (GHz)
0.01
0.1
1
10
Safely:Fmax=0.9Fc
Fmax=0.9Fc
Safely:
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular Waveguides
a
Standard Rectangular Waveguides
WR
BW TE10
(GHz)
Fc TE10
(GHz)
Power
(MW)
Attn
dB/33m
Dimensions BAND
axb (mm)
229
137
112
90
62
42
28
22
10
3.3-4.9
5.85-8.2
7.05-10.0
8.2-12.4
12.4-18
18-26.5
26.5-40
33-50
75-110
2.57
4.3
5.25
6.55
9.48
14.05
21.08
26.34
59.01
2
0.6
0.4
0.25
0.12
0.045
0.025
0.016
0.003
1
2.2
3
4.8
5.4
15
58.17x29.08
34.8x15.8
28.5x12.6
22.86x10.16
15.8x7.9
10.7x4.3
7.11x3.56
5.7x2.8
2.54x1.27
b
Multiple Modes
TEmn y TMmn
Depending on the working
frequency
Usually a=2b
Fc = c/2. [(m/a)2+(n/b)2]0.5
for TEmn on air
a
S
C
Xl
X
KU
K
KA
Q
.
.
.
.
.
.
.
.
.
Cutoff Frequency TEmn
E
b
BW TE10: 1.2FcTE10 y 1.9FcTE10
TE10
TE10 mode
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular Waveguides
a
Example: WR90 (X band)
a=22.86mm
b=10.16mm
TE20
b
b
Mode
TE10
TE20
TE01
Fc(GHz)
6.557
13.114
14.753
Fc = c/2. [(m/a)2+(n/b)2]0.5
for TEmn
TE11
TM11
16.145
16.145
Cutoff Frequency TEmn
TE30
19.671
BW TE10: 1.2Fc10 y 1.9Fc10
TE21
TM21
19.739
19.739
TE31
TM31
24.589
24.589
TE40
26.228
BW=33%
BW=33%
BRNO- march 2011
a
TM11
b
a
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular Waveguides
TE10 mode
z
Fc==2.a
2.a
λλcc==cc/ /Fc
Dispersive world:
properties vary with
frequency
Cutoff wavelength
λλoo
Empty Waveguide
-----------------λλgg==-----------------(λo/o/λλc)c)22]0.5
]0.5
[1[1––(λ
ββ==22ππ/ /λλgg
Guided wavelength
Prop. Constant
Zc==120
120π.
π.(b/a).(
(b/a).(λλg/g/λλo)
o)
Zc
Zc Power-Voltage
λg/2
Waveguide Losses in dB/m:
27.3 tan
tanδδ
27.3
-------------------------ααdd==-------------------------(Fc/F)22]0.5
]0.5
λλoo[1[1––(Fc/F)
b
27.3δδs.[1+2b/a.(Fc/F)
s.[1+2b/a.(Fc/F)22] ]
27.3
---------------------------------ααcc==---------------------------------o.b[1[1––(Fc/F)
(Fc/F)22]0.5
]0.5
λλo.b
Empty Waveguide: only conductor losses, and they are
Considerably lower with respect to a coaxial
a
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular Waveguides
Rectangular waveguide works like a
High-Pass FILTER . Cutoff frequency
is the mode cutoff.
Conductor Attenuation (dB/m)
0.4
TE10 mode
a=20 b=10mm
0.3
0.2
0.1
Fc TE20 =15.0
Fc TE10 =7.5
8.0
10.0
12.0
14.0
a
b
16.0
Freq (GHz)
Highly Dispersive Transmission Line
E
Zc (Ohm)
TE10 mode
800
TE10 mode
a=20 b=10mm
600
400
Fc TE10 =7.5
200
8.0
BRNO- march 2011
10.0
Fc TE20 =15.0
12.0
14.0
16.0
Freq (GHz)
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
SQUARE waveguides
Fc = c/2. [(m/a)2+(n/b)2]0.5
para TEmn
a
a=b Cutoff frequency TEmn
FcTEmn=FcTEnm
FcTMmn=FcTMnm
b
Example: a = b = 14.6mm
TE10 and TE01 are
Orthogonal modes
TE01
TE10
BW 10.26 y 14.5GHz
BRNO- march 2011
BW=17%
BW=17%
Mode
TE10
TE01
Fc(GHz)
10.266
10.266
TE11
TM11
14.519
14.519
TE20
TE02
20.533
20.533
TE21
TE12
TM21
TM12
22.957
22.957
22.957
22.957
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
SQUARE waveguides
Conductor attenuation in SQUARE waveguide
is lower than in RECTANGULAR waveguide
TE01
TE10
TE10 mode
TE10 and TE01 are
orthogonal modes
Conductor Attenuation (dB/m)
0.4
a=20mm b=10mm
0.3
a=20mm b=20mm
0.2
Fc TE20 =15.0
0.1
Fc TE10 =7.5
8.0
BRNO- march 2011
10.0
12.0
14.0
16.0
Freq (GHz)
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
CIRCULAR Waveguides
- Cutoff Frequencies: BESSEL functions
- Lower mode TE11: λc = 3.412 R
- immediate superior mode TM01 : λc = 2.612 R
- Can support DUAL polarization: Two orthogonal TE11 modes
R
Example: R=11mm : C97
Multiple Modes
TEmn y TMmn
depending on the working
frequency.
BW=13%
BW=13%
BRNO- march 2011
Mode
TE11
TM01
TE21
Fc(GHz)
7.98
.
10.43 .
13.25 .
TE01
TM11
16.62
16.62
.
TE31
18.22
.
TE11
.
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
CIRCULAR Waveguides
TE11
Losses are really lower than RECTANGULAR waveguides
TE11 mode
Conductor Attenuation(dB/m)
0.16
Very interesting for
Antenna feed systems
R = 15mm
0.12
0.08
Fc TM01 =7.62
0.04
Fc TE11 =5.84
6.0
BRNO- march 2011
6.5
7.0
7.5
8.0
Freq (GHz)
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
RIDGE Waveguides
Double Ridge
a
g
b
Whenusing
usingaaridge
ridge(single
(singleor
ordouble),
double),the
thefundamental
fundamentalmode
modeTE10
TE10
When
cutoff decreases
decreasesmuch
muchmore
morethan
thanthe
thecutoff
cutofffrequency
frequencyofofthe
the
cutoff
nextpropagating
propagatingmode
modeTE20.
TE20.
next
Very
Verybroadband
broadbandMONOMODE
MONOMODEoperation
operation
s
Example: Rectangular
a=22.86mm b=10.16mm (WR90)
Single Ridge
a
FcTE10 = 6.56GHz
FcTE20 = 13.11GHz
Example: Single Ridge
a=22.86mm b=10.16mm (WR90)
s=9.1mm g=2mm
FcTE10 = 3.125GHz
FcTE20 = 10.95GHz
g
b
s
BW=33%
BW=33%
BRNO- march 2011
BW=56%
BW=56%
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Mode CUTTERS
RadialWires
Wires: :
Radial
Totalreflection
reflectionfor
forthe
thefundamental
fundamentalTE11
TE11and
andall
allofofTM
TM
- -Total
Doesnot
notaffect
affectthe
thecircular
circularmodes
modesTE01,
TE01,TE02,
TE02,…
…TE0n
TE0n
- -Does
Circular Waveguide
- A given mode PASS if its E field is normal to the wires.
- If we want avoid reflection: Resistive elements
Circularwires
wiressupported
supportedby
by“foam”:
“foam”:
Circular
Totalreflection
reflectionfor
forall
allthe
theTEmn
TEmnmodes
modes
- -Total
Doesnot
notaffect
affectthe
theimmediate
immediatesuperior
superiorTM01
TM01mode
mode
- -Does
Transversalwires
wires: :
Transversal
Totalreflection
reflectionfor
forthe
thefundamental
fundamentalTE10
TE10
- -Total
Totalreflection
reflectionfor
forTE11
TE11and
andall
allthe
theTM
TMmodes
modes
- -Total
Doesnot
notaffect
affectthe
thepossible
possibleTE01
TE01mode.
mode.
- -Does
Rectangular Waveguide
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Coaxial Transducer
ELECTRICAL Probe to the TE10 mode
Coaxial TEM
z
TE10
TE10 mode
E
b
TE10
b
waveguide short
b
a
z
a
λg/4
Electrical Probes to the TE20 mode
Signals in the two coaxial probes must be
in phase.
Coaxial TEM
TE20
b
TE20 mode
a
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Coaxial Transducer
Different Improvements
short
TE10 mode
short
TE10 mode
Dielectric
short
TE10 mode
BRNO- march 2011
BroaderBandwidth
Bandwidth
Broader
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Coaxial Transducer
20dB
WR137:a=34.8
a=34.8 b=15.8mm
b=15.8mm
WR137:
TE10:5.5
5.5aa8.1
8.1GHz
GHz
TE10:
30dB
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Coaxial Transducer
MAGNETIC Probe to the TE10
z
Coax
b TE10 mode
NarrowBandwidth
Bandwidth
Narrow
z
Coax
TE10 mode
Broadband
Broadband
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Coaxial Transducer
30dB
BW 20%
WR112:a=28.5
a=28.5 b=12.6mm
b=12.6mm
WR112:
TE10:6.5
6.5aa10
10GHz
GHz
TE10:
30dB
BW 40%
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Circular Transducer
Taper Transition
TE11
Stepped Transition
TE11
TE10
Perpendicular Transition
TE10
TE11
Short
TE10
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Circular Transducer
TE11
WR112:a=28.5
a=28.5 b=12.6mm
b=12.6mm
WR112:
TE10:6.5
6.5aa10
10GHz
GHz
TE10:
BW@30dB: :18%
18%
BW@30dB
TE10
Stepped Transition
BRNO- march 2011
30dB 18%
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular-to-Circular Transducer
TE11
WR229:a=42.8
a=42.8 b=21.4mm
b=21.4mm
WR229:
TE10:3.6
3.6aa7.2
7.2GHz
GHz
TE10:
BW@30dB: :66%
66%
BW@30dB
TE10
Stepped Transition
Using Intermediate Octagons
BRNO- march 2011
35dB 66%
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Square-to-Circular Transducer
BW@30dB: :25%
25%
BW@30dB
TE10
TE01
30dB 25%
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
Step in Height
Wesuppose
supposetotobe
beoperating
operatingininaafrequency
frequencyband
bandwhere
where
- -We
theonly
onlypropagating
propagatingmode
modeisisthe
thefundamental
fundamentalone
oneTE10
TE10
the
b1
b2
z
a
Atthe
thediscontinuity,
discontinuity,high
highorder
ordermodes
modesare
areexcited
excitedbut
but
- -At
theycannot
cannotpropagate
propagateenergy
energy
They
Theystore
storeenergy
energyacting
acting
they
ascapacitors,
capacitors,inductors
inductorsor
orcombinations.
combinations.
as
Theycreate
createaareactive
reactivenetwork.
network.
- -They
High Order modes TEnm
TE10
TE10
TE10
TE10
z
Zc1
BRNO- march 2011
Reactive
Network
Zc2
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
TEnm
Whentwo
twodiscontinuities
discontinuitiesare
areclose
closeenough,
enough,
- -When
highorder
ordermodes
modesmay
may“touch”
“touch”the
thesecond
second
high
discontinuity.
discontinuity.
TE10
TE10
b
thiscase,
case,the
thereactive
reactivenetworks
networksare
are
- -InInthis
Multimodewith
withmode-transmission-lines
mode-transmission-lines
Multimode
betweenboth
bothmulti-ports.
multi-ports.
between
z
Zc10
TE10
Zc10
TE10
Reactive
Network
Zcmn
Reactive
Network
Zc10
Zcmn
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
E-Plane Step
b1
b2
Steps are Useful
for waveguide
circuits
H-Plane Step
a2
b
a
a1
jBC
Zo1
Zo2
TE10
-jBL
Zo1
TE10
(BC.Z01).(λg/b1)
Zo2
(BL.Z01).(2a1/λg)
5
1.0
4
decreaseswith
withb2
b2
CCdecreases
0.8
3
0.6
2
0.4
1
b2/b1
0
0.2
0.4
BRNO- march 2011
0.6
0.8
1.0
increaseswith
witha2
a2
LLincreases
0.2
a2/a1
0
0.2
0.4
0.6
0.8
1.0
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
d
w
diameter “d”
t
t
t
Iris-H symmetrical
Iris-circular
-jBL
Z0
Fin-H plane
Z0
For small values of t (t << a)
Useful for creating
Waveguide Circuits
jBc
Z0
BRNO- march 2011
jBc
-jBL
Z0
Additional Capacitors for
higher values of “t”
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
t
d
t
d
Iris-E symmetrical
Fin-E plane
Z0
jBC
Z0
jBc
Useful for creating
Waveguide Circuits
Z0
BRNO- march 2011
jBc
jBC
Z0
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Discontinuities in Rectangular Waveguides
Z0
jBc
jBc
C
L
jBc
jBc
Z0
Resonant Iris
C
Z0
Z0
L
Post of variable height
(square or circular)
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Matched Loads and Variable Shorts
Absorbing
material
BW: Full band
Rloss 30-40dB
Termination for “High Power”
Termination for “low VSWR”
Absorbing
Contact through
a Berillium strip
Contact
here
(HighFrequency
Frequency
(High
problems)
problems)
b
Sliding
“Contacting” variable Short
BRNO- march 2011
λ/4
λ/4
b
(Contactpoint:
point:where
wherethe
the
Sliding
(Contact
currentisisalmost
almostzero)
zero)
current
“Non-contacting” variable Short
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Differential Phase-Shifter “Narrow Band”
a
L
a’
E.ejΦ1
E.ejΦ2
Enun
untramo
tramode
deguía
guíavacío
vacío“L”
“L”laladiferencia
diferenciade
defase
fase
- -En
o2- -ΦΦo1
o1es
es∆φv
∆φv
v.Lyyvaría
varíacon
conlalafrecuencia.
frecuencia.
∆φ ==––ββv.L
ΦΦo2
∆φ
Ahoraqueremos
queremosconstruir
construirun
uncircuito
circuitode
deforma
formaque
que
- -Ahora
su∆Φd
∆Φd
(variablecon
conlalafrecuencia)
frecuencia)sea
seatal
talque
quealalcomcom∆Φ (variable
su
∆Φ
pararlocon
conlalaguía
guíavacía
vacíaresulte
resulteen
enun
undiferencial:
diferencial:
pararlo
∆Φd
∆Φv
cte==∆Φ
∆Φdeseada
deseada(tip.
(tip.45º,
45º,90º,
90º,180º)
180º)
∆Φ ––∆Φv
∆Φ ==cte
∆Φd
∆Φ
∆Φ
DPS by narrowing “a”
Una forma evidente es ensanchar ò estrechar la guía
puesto que la constante de propagación β varía con “a”
TE10 mode
∆Φ==[β[βvv––ββd].L
d].L==[2[2ππ/λ
/λgv
gv––22ππ/λ
/λgd].L
gd].L
∆Φ
Fc==2.a
2.a
λλcc==cc/ /Fc
λλoo
-----------------λλgg==-----------------(λo/o/λλc)c)22]0.5
]0.5
[1[1––(λ
ββ==22ππ/ /λλgg
BRNO- march 2011
Detalles:
- Al reducir la guía cambiamos su Fc el ancho de banda
de trabajo se restringe.
- El salto entre guías afectará a la adaptación del desfasador
- El cambio de fase deseado se verificará en un BW estrecho
ya que ∆Φ varía con la frecuencia.
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Differential Phase-Shifter “Narrow Band”
L
Unaforma
formaalternativa
alternativaconsiste
consisteen
enintroducir
introducirreactancias
reactancias
Una
enlalaguía
guíavacía.
vacía.Si
Sieleldiseño
diseñoes
escorrecto,
correcto,las
lasreflexiones
reflexiones
en
debidasaaestos
estoselementos
elementosse
secancelan
cancelanmientras
mientrasque
que
debidas
susefectos
efectosde
defase
faseson
sonaditivos
aditivos
sus
d
Si llamamos BLn al valor normalizado de BL: BLn=BL.Zo
entonces la matriz ABCD normalizada de la red es:
a
Desfasador con doble discont.
L
Z0
-jBL
Z0
-jBL Z0
An Bn =
1 0
Cn Dn
-jBLn 1
cos(β
βL) jsin(β
βL)
jsin(β
βL) cos(β
βL)
1 0
-jBLn 1
Si la impedancia de entrada norm. Zin_n=(An+Bn)/(Cn+Dn)
debe ser unidad para que exista adaptación, y ya que An=Dn
entonces necesitamos Cn=Bn por lo que:
β.L==ππ/2/2++arctan(BLn/2)
arctan(BLn/2)
β.L
β.β.
Por otro lado, el cambio de fase diferencial es:
- Al contrario ocurre si introducimos
reactancias capacitivas.
- Circuito de banda estrecha y sensitivo
con la frecuencia
BRNO- march 2011
∆Φ==β.L
π/2/2––arctan(BLn/2)]
arctan(BLn/2)]
β. ––[π
π[π
∆Φ
β.β.L
∆Φ==2.artan(BLn/2)
2.artan(BLn/2)
∆Φ
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Differential Phase-Shifter “Broadband”
Low-Pass type
40 dB
Capacitive Iris
90º +/- 2º
Capacitive Ridge
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Waveguide Junctions
3
3
2
1
1
E-plane T junction
(Magnetic Symmetry)
2
Port 3 Splits the input signal in 180º
3
- The THREE ports cannot be matched
simultaneously.
Z’0
- Port 3 splits power in phase opposition 180º, but
power splitting is not 3db due to mismatching.
1
Z0
Z0
2
- If port 3 is matched, power splitting is 3dB but S11
and S22 will have 6dB return loss.
-jX
Equivalent Circuit: Series connection
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Waveguide Junctions
H-Plane T junction
(Electrical Symmetry)
1
2
Port 3 Splits the input signal in 0º
3
- The THREE ports cannot be matched
simultaneously.
1
Z0
-jX
Z0
2
- Port 3 splits power in phase 0º, but power splitting
is not 3db due to mismatching.
Z’0
3
- If port 3 is matched, power splitting is 3dB but S11
and S22 will have 6dB return loss.
Equivalent Circuit: Parallel connection
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Hybrid Waveguide Junctions – Magic Tee
-Ports 1 and 2 decoupled
-Ports 3 and 4 decoupled
-Power splitting in 0º and 180º
3
1
Magic-T.- Completely matched Hybrid T.
It is necessary to introduce some discontinuities
In the junction.
- In this case, power splitting is always 3dB.
2
Iris
Hybrid T
4
3
Usefulas
asPower
PowerDivider
Divider
Useful
orPower
PowerCombiner
Combiner0º
0ºòò180º
180º
or
Example:
IN
(Sum)
Post
(Difference)
3
1
4
2
4
IN
BRNO- march 2011
BW: 10-20%
Magic-T
1
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Hybrid Waveguide Junctions – Magic Tee
iris
Usefulas
asPower
PowerDivider
Divider
Useful
orPower
PowerCombiner
Combiner0º
0ºòò180º
180º
or
Optimized Magic-T
BW : 12%
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Four-Port Waveguide junction (rat trace)
4
Zo/√2
b
Usefulas
asPower
PowerDivider
Divider
Useful
orPower
PowerCombiner
Combiner0º
0ºòò180º
180º
or
Zo
1
λg/4
2
3
3λg/4
BW: 10%
-Ports 1 and 2 decoupled
-Ports 3 and 4 decoupled
-(1) splits toward (3) and (4) in phase opposition (3dB).
-(4) splits toward (1) and (2) in phase (3dB).
BRNO- march 2011
Path differences
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Waveguide Couplers xdB
3
4
-3 dB
isolation +
matching
BW: 10%
H-plane branch coupler
1
2
Asymmetric power division
Slot Coupler
BW: 20%
isolation
matching
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
3dB – 90º Couplers
4
λ /4
3
Homonym in
microstrip
1
3dB Ribblet coupler
2
Usefulas
asPower
PowerDivider
Divider
Useful
orPower
PowerCombiner
Combiner90º
90º
or
Phase shift : 90º
BW: 20%
coupling 3dB
isolation +
matching
BW: 20 - 30%
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Rectangular Waveguide Filters
C3
L3
C1
Some examples for Inverters
L1
Discrete Pass-Band circuit
λgo/4
K,J
Zc , Yc
K = Zc
J = Yc
K1
C3
L3
Zin , Yin
K2
C1
L1
Zin = Zc2/ZL @ Fo
Yin = Yc2/YL @ Fo
(a)
C1
ZL
L1
−θ
−θ
+θ
+θ
Zc
Zc
K Inverters
Using Inverters
Zc
L
Zc
X = K / [ 1 - ( K / Zc )2 ]
θ = 1/2 | ATN ( 2X / Zc ) |
C
X=LW
+θ
X=-1/CW
+θ
−θ
−θ
J Inverters
K1
K2
L
Yc
Yc
B=-1/LW
Inverters + waveguide sections
BRNO- march 2011
B = J / [ 1 - ( J / Yc )2 ]
θ = 1/2 | ATN ( 2B / Yc ) |
(b)
Yc
C
Yc
B=CW
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Band-Pass Waveguide Filters
BW : 6 - 15%
Symmetrical Iris
Asymmetrical Iris
Z0
Symmetrical pairs of Posts
BRNO- march 2011
-jBL
Z0
E-plane Fins
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Low-Pass Waveguide Filters
Destroys2nd
2ndHarmonic
Harmonicinin
Destroys
Microwavetransmitters
transmitters
Microwave
Low-pass
topology
2nd harmonic area
Element
t
d
Symmetrical E-plane Iris
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Elliptic Waveguide Filters
Short circuit
Transmission
zero
Transmission
Transmission
Zero
Zero
Conventional
section
E-plane Tee +
Series Stub
3
2
1
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
Elliptic Waveguide Filters
SupplementaryRejection
Rejection
Supplementary
oneside
sideofofthe
thefilter
filter
atatone
Transmission
zero
Important
slope
Short circuit
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
DUPLEXERS
TX
RX
Toselect
selecttwo
twodifferent
differentfrequency
frequencybands
bands
To
(intheory
theorycompletely
completelyisolated)
isolated)
(in
TX
Common Port
Towards the antenna
BRNO- march 2011
RX
isolation
TX-RX
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
DUPLEXERS (variants)
septum
matching
network
H-plane duplexer
(matched T)
H-plane duplexer
(septum)
Multi-step
for matching
E-plane duplexer
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
ORTHOMODE JUNCTIONS (OMT)
thecommon
commonwaveguide
waveguideTX
TXand
andRX
RX
- -InInthe
areorthogonal:
orthogonal:infinite
infiniteisolation.
isolation.
are
TE10
TX
Operationininthe
thesame
sameband
bandor
orinin
- -Operation
differentfrequency
frequencybands
bands
different
TE10
RX
TX
RX
TE11
BW: 10-15%
TE11
Common output
“CIRCULAR”
(towards the antenna)
TE01
Common output
“SQUARE”
(towards the antenna)
BRNO- march 2011
TE10
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
DUAL-BAND ORTHOMODE
Rx
Tx
WR75:Ku
Kuband
band
WR75:
transmission
Common output
“SQUARE”
(towards the antenna)
BRNO- march 2011
Rx
Tx
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
POLARIZERS for Circular Polarization
TE10
-To convert a LINEAR polarization to a
CIRCULAR polarization:
TE01
TE10
(lineal)
Transformador
adaptación
Sección
Circular
Phaseshift
shiftbetween
between
Phase
TE10and
andTE01
TE01isis
TE10
ZEROº
ZEROº
BW:40%
40%
BW:
BRNO- march 2011
1º.- Split the input signal TE10 into two
orthogonal modes TE10 and TE01 through
the use of a square waveguide rotated 45º
2º.- Delay one mode with respect to the other
by 90º.
S22 for TE10 or TE01
(6dB)
S21 for TE10 or TE01
(3dB)
matching
S11 (<-30dB)
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
POLARIZERS for Circular Polarization
TE11c
- Same idea but using octagonal sections
TE11s
TE10
TE01
(linear)
Circular
output
Transformador
adaptación
Phaseshift
shiftbetween
between
Phase
TE10and
andTE01
TE01isis
TE10
ZEROº
ZEROº
BW:66%
66%
BW:
BRNO- march 2011
S21 for TE10 or TE01
(3dB)
matching
S11 (<-30dB)
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
POLARIZERS for Circular Polarization
Using E-plane iris
TE10
TE01
TE10mode
modeisisdelayed
delayed90º
90ºwith
withrespect
respecttotoTE01
TE01mode
mode
TE10
TE10
90º
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
POLARIZERS for Circular Polarization
Using Ridge waveguide
TE10mode
modeisisdelayed
delayed90º
90ºwith
withrespect
respecttotoTE01
TE01mode
mode
TE10
TE01
TE10
65%
BRNO- march 2011
9 GHz
90º +/- 4º
17.5 GHz
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – CIRCULAR POLARIZATION
RX
TX
The same for RX
but LHCP
3dB division
3dB with phase-shift of +90º
(RHCP)
Port matching
isolation TX-RX
Detail
BRNO- march 2011
BW 20%
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – BROADBAND LINEAR POLARIZATION
Turnstile Junction
BRNO- march 2011
Navarrini et al.
“A Turnstile Waveguide Junction
Orthomode Transducer”
IEEE Trans. on MTT, jan. 2006
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – BROADBAND LINEAR POLARIZATION
Isolation > 50dB
Typ. 60dB
BW@25dB: :28%
28%
BW@25dB
We can do
better
BRNO- march 2011
BW@25dB: :40%
40%
BW@25dB
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – BROADBAND LINEAR POLARIZATION
Turnstile Based
(evolution)
(60% Bandwidth)
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – BROADBAND LINEAR POLARIZATION
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
OMT – BROADBAND LINEAR POLARIZATION
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
MODE CONVERTER TE11 to TM01
Transition from “a traditional circular TE11” to a “special circular TM01”
TM01 mode:
null for the electric field along the waveguide axis
to conduct electron beams or circuitry
Null for the
Electric field
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
MODE CONVERTER TE11 to TM01
BW: 50%
S 21 (TM 01 )(TE11 )
Radiation Diagram for the TM01 mode
S 22 (TE11 )
9.6GHZ
BRNO- march 2011
S11 (TM 01 )
15.6GHz
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
C-band FOUR-PORT RECEIVER / TRANSMITTER
IN: RX:
RX:3.6
3.6––4.8
4.8GHz
GHz (30%
(30%BW)
BW)
IN:
TX:5.8
5.8––7.0
7.0GHz
GHz (20%
(20%BW)
BW)
TX:
OUT
TX
Common
circular
output
TE11
Duplexer TX/RX
CPR229
OMT TX/RX
TX
RX
Satellite Link
control
RX
BRNO- march 2011
CPR159
OUT:
OUT:
HorizontalTX
TXand
andRX
RX
Horizontal
VerticalTX
TXand
andRX
RX
Vertical
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
C-band FOUR-PORT RECEIVER / TRANSMITTER
Explode View
Satellite Link
control
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
C-band FOUR-PORT RECEIVER / TRANSMITTER
Duplexer detail
TX
Low-Pass filter
Towards OMT
BRNO- march 2011
RX
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
RADIOASTRONOMY: Cosmic Microwave Background
Measure the degree of Circular Polarization existing in the Cosmic microwave
radiation.
Alternative Broadband
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
RADIOASTRONOMY: Cosmic Microwave Background
System using 2 turnstile at 45º and
180º phase shifters
Alternative using Coaxial Probes
Polarised
Signal
Spin
Polariser
Output rotates
x2
Orthogonal outputs
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
TRACKING: following a Target
Radiation diagram
TE11
RX (Ku)
TX (Ku)
TM01
(Towards the antenna)
TE11 mode: Useful signal
TM01mode : Tracking
Tracking Port
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
FUTURE
Limit is our Imagination
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA
BRNO- march 2011
Dpto. Ingeniería de Comunicaciones Universidad de CANTABRIA