8. 8
Where Are We? 1. Introduction
2. Transmission Line Basics
1. Transmission Line Theory
2. Basic I/O Circuits
3. Reflections
4. Parasitic Discontinuities
5. Modeling, Simulation, & Spice
6. Measurement: Basic Equipment
7. Measurement: Time Domain Reflectometry
3. Analysis Tools
4. Metrics & Methodology
5. Advanced Transmission Lines
thenhan 12/16/2011
9. 9
CzoPnrotpeangattsion Velocity
z Characteristic Impedance
z Visualizing Transmission Line Behavior
z General Circuit Model
z Frequency Dependence
z Lossless Transmission Lines
z Homogeneous and Non-homogeneous Lines
z Impedance Formulae for Transmission Line
Structures
z Summary
z References
thenhan 12/16/2011
10. y
I+ d I dz
dz
V+ d V dz
z
x
[2.1.1]
[2.1.2]
I
V
C V
I
∂
∂
= −
Ldz
Cdz
dz
dz
V, I
the Telegraphist’s Equations [2.1.3a]
[2.1.3b]
10
Wave propagates in z Propagation direction
Velocity
z Physical example:
9 Circuit: L = [nH/cm]
C = [pF/cm]
V
dz ( Ldz )
I
z
∂
t
∂
∂
9 Total voltage change across = −
∂
Ldz (use Δ V L d I ):
= − dt
9 Total current change across
ΔI = −C dV
Cdz (use d t ):
I
∂
dz ( Cdz )
V
z
t
∂
∂
∂
= −
9 Simplify [2.1.1] & [2.1.2] to get
t
∂
L I
∂
t
z
∂
V
∂
z
∂
∂
= −
thenhan 12/16/2011
11. 2 2
C V
I
∂
∂
9 Differentiate [2.1.3a] by t: 2 [2.1.4]
t
z t
∂
= −
∂ ∂
∂ 2
L I
2
V
∂
9 Differentiate [2.1.3b] by z: [2.1.5]
2
t z
z
∂ ∂
= −
∂
2
2 2
1
V
LC V
V
∂
∂
∂
9 Equate [2.1.4] & [2.1.5]: [2.1.6] 2
[2.1.7]
[2.1.8]
11
Propagation Velocity (2)
∂
9 Equation [2.1.6] is a form of the wave equation. The solution to
[2.1.6] contains forward and backward traveling wave
components, which travel with a phase velocity.
9 Phase velocity definition: v
2
z
=
≡ 1
LC
9 Equation in terms of current:
t
∂
I
2
2
=
2 2
t
∂
ν
2 1
LC I
=
2 2
2
I
2
t
t
z
∂
∂
∂
∂
=
∂
∂
ν
An alternate treatment of propagation velocity is contained in the appendix.
thenhan 12/16/2011
12. dz = segment length
C = capacitance per segment
L = inductance per segment
12
Z1 Z2 Z3
Characteristic Impedance
b c
Ldz
(Lossless)
V1 V2 V3 Cdx
to ∞
Ldz
Cdz
Ldz
Cdz
d e f
dz dz
a
dz
z The input impedance (Z1) is the impedance
of the first inductor (Ldz) in series with the
parallel combination of the impedance of
the capacitor (Cdz) and Z2.
[2.1.9]
( )
Z j Cdz
Z j Ldz Z j ω
Cdz
ω
= ω
+
1/
2
1/
2
1 +
( 1/ ) ( 1/ ) (1/ ) 0 1 2 2 2 Z Z + jωlC − jωlL Z + jωlC − Z jωlC =
thenhan 12/16/2011
13. 13
Characteristic Impedance
(Lossless)
z Assuming a uniform line, the input
impedance should be the same when
looking into node pairs a-d, b-e, c-f, and so
fo( rth1./ So, Z) 2 = Z(1= 1Z/0. ) (1/ ) 0 0 0 0 0 Z Z + jωCdz − jωlLdz Z + jωCdz − Z jωCdz = [2.1.10]
ω
Z j LZ dz j Ldz
j Cdz
Z
2
0
2 0
0 0
+ − − − 0
= = − 0
− j Cdz
ω
j LZ dz Ldz
Cdz
Z Z
j Cdz
ω
ω
ω ω
ω
ω
0
Z 2
− jωLZ L 0 0
dz − =
0 [2.1.11]
C
9 Allow dz to become very small, causing the frequency
dependent term to drop out:
Z L [2.1.12]
2 0
0 − =
C
9 Solve for Z0:
Z = L 0
C
[2.1.13]
thenhan 12/16/2011
14. 14
Visualizing Transmission Line
h
Behavior
f
z Water flow
– Potential = Wave
height [m]
– Flow = Flow rate
[liter/sec]
I
+++++++
- - - - - - -
I
V
9 Transmission Line
¾ Potential = Voltage [V]
¾ Flow = Current [A] =
[C/sec]
9 Just as the wave front of the water flows in the pipe, the
voltage propagates in the transmission line. The same
holds true for current.
¾ Voltage and current propagate as waves in the transmission line.
thenhan 12/16/2011
15. 15
Visualizing Transmission Line
Behavior #2
z Extending the analogy
– The diameter of the pipe relates the flow rate
and height of the water. This is analogous to
electrical impedance.
– Ohm’s law and the characteristic impedance
define the relationship between current and
potential in the transmission line.
z Effects of impedance discontinuities
– What happens when the water encounters a
ledge or a barrier?
– What happens to the current and voltage
waves when the impedance of the
transmission line changes?
thenhan 12/16/2011
16. 16
General Transmission Line
Model (No Coupling)
z Transmission line parameters are
distributed (e.g. capacitance per unit
length).
R L
R L
R L
z A G C
transmission line can G be C
modeled G C
using
a network of resistances, inductances, and
capacitances, where the distributed
parameters are broken into small discrete
elements.
thenhan 12/16/2011
17. ω
ω [2.1.14]
Propagation Constant γ = (R + jωL)(G + jωC) =α + jβ [2.1.15]
α = attenuation constant = rate of exponential attenuation
β = phase constant = amount of phase shift per unit length
ν = Phase Velocity p [2.1.16]
In general, α and β are frequency dependent.
17
General Transmission Line
Model #2
Symb Units
ol
Parameters Parameter
Conductor R Ω•cm-1
Resistance
Self Inductance L nH•cm-1
Total Capacitance C pF•cm-1
Ω-1•cm -
1 Dielectric G
Conductance
Characteristic Impedance Z R j L
+
+
0 G j C =
ω
β
thenhan 12/16/2011
18. 18
Frequency Dependence
From [2.1.14] and [2.1.15] note that:
z Z0 and γ depend on the frequency content
of the signal.
z Frequency dependence causes attenuation
and edge rate degradation.
Attenuation
Output signal from lossy
transmission line
Output signal from
lossless transmission line
Edge rate degradation
Signal at driven end of
transmission line
thenhan 12/16/2011
19. 19
FrzeRqaunede nGncarye sDomeeptiemnesd neegnlicgiebl e#, 2
particularly at low frequencies
– Simplifies to the lossless case: no attenuation
& no dispersion
z In modules 2 and 3, we will concentrate on
lossless transmission lines.
z Modules 5 and 6 will deal with lossy lines.
thenhan 12/16/2011
20. H E
20
Lossless Transmission Lines
Quasi-TEM Assumption
z The electric and magnetic fields are
perpendicular to the propagation velocity
in the transverse planes.
x
y z
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21. 21
z Lossless transmission lines are characterized
by the following two parameters:
Lossless Line Parameters
Z = L 0
C
v
= 1
LC
Characteristic Impedance
Propagation Velocity
z Lossless line characteristics are frequency
independent.
z As noted before, Z0 defines the relationship
between voltage and current for the traveling
waves. The units are ohms [Ω].
z υ defines the propagation velocity of the
waves. The units are cm/ns.
thenhan 12/16/2011
S ti th ti dl
[2.1.17]
[2.1.18]
22. 22
Lossless Line Equivalent Circuit
L
L
L
z The transmission line equivalent circuit
shown C
on the C
left is C
often represented by
the coaxial cable symbol.
Z0Z, 0ν, ,v l,e lnegntghth
thenhan 12/16/2011
23. [2.1.19]
23
Homogeneous Media
z A homogeneous dielectric medium is
uniform in all directions.
– All field v
= 1 lines = are 1 = 0 = contained 30
within the
dielectric.
LC
c cm /
ns
εμ ε μ ε
r r r
0 ε ε ε r = Dielectric Permittivity
εNote: only r
r
εz For a ε 0 = 8.854 x transmission 10− 14 F
line in a Permittivity of free homogeneous
space
medium, μ the cm
8 0 =1.257 x 10− H
propagation velocity depends
only on material cm
properties:
Magnetic Permeability
0 μ ≅ μ Permeability of free space
εr
is the relative permittivity or dielectric constant.
is required to
calculate νν.
thenhan 12/16/2011
24. 24
Non-Homogeneous Media
z A non-homogenous medium contains
multiple materials with different dielectric
constants.
z For a non-homogeneous medium, field
lines cut v
= 1 ≠ 1
across LC
the εμ
boundaries between
dielectric materials.
z In this case the propagation velocity
depends on the dielectric constants and the
proportions of the materials. Equation
[2.1.19] does not hold:
9 In practice, an effective dielectric constant, εr,eff is
often used, which represents an average dielectric
constant.
thenhan 12/16/2011
25. 25
Some Typical Transmission
Line Structures
And useful formulas for Z0
thenhan 12/16/2011
26. 26
r
R
εr
Trởở kháng cáp đđồồng trụục
εr = 2
εr = 2.5
εr = 3
2 3 4 5 6 7 8 9 10
R/r
140
120
100
80
60
40
20
⎞
Z = 1
ln ⎛
R
0 ε
2πε
⎞
⎛
R
⎞
μ
L = ln ⎛
R
thenhan 12/16/2011
Z0 [ Ω]
εr
= 1
εrr= 4 ε = 3.5
, lZe0n, gυth, vle, n0gZth
⎟⎠
⎜⎝
r
2
μ
π
[2.1.20]
⎟⎠
⎜⎝
=
r
C
ln
[2.1.21]
⎟⎠
⎜⎝
r
2π
[2.1.22]
27. ⎞
h
4
60 ln 2
( )⎟ ⎟ ⎟
⎠
w
0.35
0.25
27
Centered Stripline Impedance
⎛
⎜ ⎜ ⎜
0 ε π
r 0.67 0.8
⎝
w +
t
=
Z
w
t
h1
h2
εr
Source: Motorola
application note
AN1051.
Valid for w
h −t
2
<
h <
2
t
60 Z0 [Ω]
55
50
45
40
35
30
25
20
15
h2
0.003 0.005 0.007 0.009 0.011 0.013 0.015
thenhan 12/16/2011
w [in]
10
0.070
0.060
0.050
0.040
0.030
0.025
0.020
t = 0.0007”
εr = 4.0
28. [2.1.24]
[2.1.25]
[2.1.26]
[2.1.27]
28
Dual Stripline Impedance
w
h1
t
h2
Z YZ
⎞
⎛
Y h
60 ln 8 1
ε π
⎞
⎛
Z h h
60 ln 8 1 2
ε π
⎤
1
h h t h t
ln ⎡
1.9 2
+
⎤
⎡
⎞
⎛
110
100
90
80
70
60
50
40
30
20
thenhan 12/16/2011
εr
w
t
h1
Y +
Z
= 2
0
( )⎟ ⎟ ⎟
⎠
⎜ ⎜ ⎜
⎝
+
=
w
w t
r 0.67 0.8
( )
( )⎟ ⎟ ⎟
⎠
⎜ ⎜ ⎜
⎝
+
+
=
w
w t
r 0.67 0.8
( ) ( )
⎥⎦
⎢⎣
+
⎥⎦
⎢⎣
⎟ ⎟⎠
⎜ ⎜⎝
+ +
−
=
w t
h
Z
r 0.8
4
80 1
1 2 1
0 ε
1 1. 0.5h ≤ w ≤ h
Source: Motorola
application note
AN1051.
OR
0.003 0.005 0.007 0.009 0.011 0.013 0.015
w [in]
10
Z0 [ Ω]
0.020”
0.018”
0.015”
0.012”
0.010”
0.008”
0.005”
2h1 + h2 + 2t = 0.062”
t = 0.0007”
εr = 4.0
h1
29. 29
Surface Microstrip Impedance
w
t
h
⎞
Z = 1
⎛
h
0 ε
⎞
Z h
ln ⎛
5.98
87
160
140
120
100
80
60
40
h
thenhan 12/16/2011
ε0
εr
[ ] Ω ⎟⎠
⎜⎝
d
eff
ln 4
2
μ
π
d = 0.536w+ 0.67t
( ) 0 ε = 0.475ε + 0.67 ε eff r
[ ] Ω ⎟⎠
⎜⎝
+ +
=
w t
r 1.41
0.8
0 ε
0.003 0.005 0.007 0.009 0.011 0.013 0.015
w [in]
20
Z0 [Ω]
0.025”
0.020”
0.015”
0.012”
0.009”
0.006”
0.004”
t = 0.0007”
εr
= 4.0
[2.1.28]
[2.1.29]
[2.1.30]
[2.1.31]
30. [2.1.32]
[2.1.33]
[2.1.34]
[2.1.35]
30
Embedded Microstrip
t
h1
ε0
εr
w
h2
⎞
⎟⎠
Z K ln ⎛
5.98
h
⎜⎝
1
w t
0 ε
where 60 ≤ K ≤ 65
r 0.8
+ +
=
0.805 2
⎞
⎟⎠
Z h
ln 5.98
87 ⎛
1
⎜⎝
0 ε
[1 1.55h2 h1 ]
r r eε ′ =ε − −
=1.017 0.475 + 0.67 r ε
w t
r 0.8
′ + +
=
1.41
τ
Or
140
120
100
80
60
40
20
0
h1
0.015”
0.012”
0.010”
0.008”
0.006”
0.005”
0.003”
h2 - h1 = 0.002“
t= 0.0007”
εr
= 4.0
0.003 0.005 0.007 0.009 0.011 0.013 0.015
w [in]
Z0 [Ω]
thenhan 12/16/2011
31. 31
Summary
z System level interconnects can often be
treated as lossless transmission lines.
z Transmission lines circuit elements are
distributed.
z Voltage and current propagate as waves in
transmission lines.
z Propagation velocity and characteristic
impedance characterize the behavior of
lossless transmission lines.
z Coaxial cables, stripline and microstrip
thenhan 12/16/2011
32. 32
References
z S. Hall, G. Hall, and J. McCall, High Speed
Digital System Design, John Wiley & Sons, Inc.
(Wiley Interscience), 2000, 1st edition.
z H. Johnson and M. Graham, High-Speed Signal
Propagation: Advanced Black Magic, Prentice
Hall, 2003, 1st edition, ISBN 0-13-084408-X.
z W. Dally and J. Poulton, Digital Systems
Engineering, Cambridge University Press, 1998.
z R.E. Matick, Transmission Lines for Digital and
Communication Networks, IEEE Press, 1995.
z R. Poon, Computer Circuits Electrical Design,
Prentice Hall 1st edition 1995
thenhan 12/16/2011
33. 33
BẢẢN CHẤẤT CỦỦA QUÁ TRÌNH
TRUYỀỀN SÓNG
z THỰC CHẤT LÀ ĐƯỜNG DÂY
TRUYỀN SÓNG TRUYỀN NĂNG
LƯỢNG DƯỚI DẠNG SÓNG CAO TẦN
z QUÁ TRÌNH TRUYỀN NÀY CÓ VẬN
TỐC NHẤT ĐỊNH
z ĐIỆN ÁP VÀ DÒNG ĐIỆN THAY ĐỔI
TƯƠNG ỨNG THEO
thenhan 12/16/2011
37. 37
PHƯƯƠƠNG TRÌNH TRUYỀỀN SÓNG
TRÊN ĐĐƯƯỜỜNG DÂY
HỆ PHƯƠNG TRÌNH
MAXWELL
r
E B
t
∂
∂
= −
r
rot
r
H J D
t
∂
∂
r r
= +
rot
ρ = D r
div
0 div = B r
thenhan 12/16/2011
38. 38
MÔ HÌNH VẬẬT LÝ
S Z
i(x,t) i(x + Δz,t)
S V L Z
+
-
v(x,t) v(x + Δz,t)
x x + Δx l
thenhan 12/16/2011
39. 39
MÔ HÌNH VẬẬT LÝ
S Z
i(x,t) i(x + Δz,t)
S V L Z
+
-
v(x,t) v(x + Δz,t)
x x + Δx l
i(x + Δz,t)
v(x + Δz,t)
x x + Δx
i(x,t)
v(x,t)
i(x,t) i(x + Δz,t)
v(x,t) v(x + Δz,t)
thenhan 12/16/2011
42. 42
i(x,t) i(x + Δz,t)
LΔx
GΔx CΔx
RΔx
v(x,t) v(x + Δz,t)
x x + Δx
( ) ( ) ( ) v(x x t)
v x,t RΔx i x,t LΔx i x,t + + Δ ,
x
∂
∂
= • + •
( ) ( ) ( ) i(x x t)
∂ +
Δ
i x,t = G Δ x • v x + Δ x,t + C Δ x •
v x x,t + +
Δ ,
x
∂
thenhan 12/16/2011
55. 55
TRỞỞ KHÁNG ĐĐẶẶC TÍNH CỦỦA
ĐĐƯƯỜỜNG DÂY 0 Z
thenhan 12/16/2011
56. 56
TẢẢI TRÊN ĐĐƯƯỜỜNG DÂY
TRUYỀỀN SÓNG
thenhan 12/16/2011
57. 57
+
V0
S V L Z
+
-
HỆỆ SỐỐ PHẢẢN XẠẠ
S Z
z
l
−
V0
Z0 ,β
d
thenhan 12/16/2011
PS
( ) + − j β d
− j β d
Ii z = I 0 e Ir ( z ) = I 0
e ( ) j d
Vi z V e = + − β 0
( ) j d
Vr z V e = − β 0
−
VL
+|L
V
58. 58
HỆỆ SỐỐ PHẢẢN XẠẠ TẠẠI TẢẢI
0
0
Z Z
L
−
−
Γ ≡ = +
L +
Z Z
V
V
L
L
L
thenhan 12/16/2011
59. Γ d = V d = Γ • −2 β
j d
59
HỆỆ SỐỐ PHẢẢN XẠẠ TẠẠI MỘỘT ĐĐiỂỂM
TRÊN ĐĐƯƯỜỜNG DÂY
( ) ( )
r e
V ( d
)
L
i
d = l − z
thenhan 12/16/2011
60. 60
HỆỆ SỐỐ PHẢẢN XẠẠ CÔNG SUẤẤT
+
-
Z0 ,β
thenhan 12/16/2011
S Z
S V L Z
z
l
+
V0
−
V0
d
Pi (z)
Pr (z)
Pi (l)
Pr (l)
PL
PS
Pi (0)
Pr (0)
61. 61
HỆỆ SỐỐ PHẢẢN XẠẠ CÔNG SUẤẤT
P
i
2 ( )2 d
Γ = r = Γ
P
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62. 62
CÁC TRƯƯỜỜNG HỢỢP ĐĐẶẶC BIỆỆT
TẢẢI NGẮẮN MẠẠCH
Z R
L
0
L
−
Γ =
L +
Z R
0
1
0
0
R
0 = −
R
0
Vi (l) = −Vr (l)
V(l) = Vi (l)+Vr (l) = 0
−
+
=
ΓL
thenhan 12/16/2011
63. 63
Z0 ,β
thenhan 12/16/2011
+
-
TRỞỞ KHÁNG ĐĐƯƯỜỜNG DÂY
S Z
S V L Z
d l
Z(d )
ZIN
64. Z d Z Z jZ β
d
( )Ω
64
TRỞỞ KHÁNG TẠẠI ĐĐiỂỂM CÁCH TẢẢI
MỘỘT KHOẢẢNG d
( ) L
+
0
tan
( )
Z +
jZ d
=
L
β
tan
0
0
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85. 85
CÁC TRƯƯỜỜNG HỢỢP ĐĐẶẶT BIỆỆT
z ĐƯỜNG DÂY NGẮN
MẠCH TẢI
( ) ( )
+
β
Z d Z Z L
jZ 0
tan
d
Z jZ ( d )
=
in β
L
tan
0 +
0
Zin (d ) jZ ( d ) 0 tan β =
= 0 ZL
thenhan 12/16/2011
86. 86
CÁC TRƯƯỜỜNG HỢỢP ĐĐẶẶT BIỆỆT
z ĐƯỜNG DÂY HỞ
MẠCH TẢI
( ) ( )
+
β
Z d Z Z L
jZ 0
tan
d
Z jZ ( d )
=
in β
L
tan
0 +
0
Zin (d ) jZ ( d ) 0 cotan β = −
= ∞ ZL
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87. 87
ĐĐƯƯỜỜNG TRUYỀỀN MỘỘT PHẦẦN
TƯƯ BƯƯỚỚC SÓNG
( ) ( )
+
β
Z d Z Z L
jZ 0
tan
d
Z jZ ( d )
=
in β
L
tan
0 +
0
Z ( )
Z
2
λ 4 = 0
L
in Z
β = 2
π
λ
λ
4
d =
thenhan 12/16/2011
90. 90
Frequency Dielectric Comments and history
"Bayonet type-N connector", or "Bayonet Neill-
Concelman" according to Johnson
Components. Developed in the early 1950s
at Bell Labs. Could also stand for "baby N
connector".
"Sub-miniature type B", a snap-on subminiature
connector, available in 50 and 75 ohms.
Limit
Connector type
BNC 4 GHz PTFE
SMB 4 GHz PTFE
OSMT 6 GHz PTFE A surface mount connector
MCX was the original name of the Snap-
On"micro-coax" connector species. Available
in 50 and 75 ohms.
Micro-miniature coax connector, popular in the
wire industry because its small size and
cheap price.
Sub-miniature type C, a threaded subminiature
connector, not widely used.
Sub-miniature type A developed in the 1960s,
perhaps the most widely-used microwave
connector system in the universe.
"Threaded Neill-Concelman" connector,
according to Johnson Components, it is
actually a threaded BNC connector, to
reduce vibration problems. Carl Concelman
was an engineer at Amphenol.
OSX, MCX, PCX 6 GHz PTFE
MMCX PTFE
SMC 10 GHz PTFE
SMA 25 GHz PTFE
TNC 15 GHz PTFE
thenhan 12/16/2011
91. 91
Named for Paul Neill of Bell Labs in the 1940s,
available in 50 and 75 ohms. Cheap and
rugged, it is still widely in use. Originally was
usable up to one GHz, but over the years this
species has been extended to 18 GHz, including
work by Julius Botka at Hewlett Packard.
APC-7 stands for "Amphenol precision connector",
7mm. Developed in the swinging 60s, ironically
a truly sexless connector, which provides the
lowest VSWR of any connector up to 18 GHz.
OSP stands for "Omni-Spectra push-on", a blind-mate
connector with zero detent. Often used in
equipment racks.
A precision (expensive) connector, it mates to
cheaper SMA connectors.
OSP stands for "Omni-Spectra subminiature push-on",
a smaller version of OSP connector.
11 GHz PTFE
normal
18 GHz
precision
APC-7, 7 mm 18 GHz PTFE
OSP 22 GHz PTFE
3.5 mm 26.5 GHz Air
OSSP 28 GHz PTFE
SSMA 38 GHz PTFE Smaller than an SMA.
Precision connector, developed by Mario Maury in
1974. 2.92 mm will thread to cheaper SMA and
3.5 mm connectors. Often called "2.9 mm".
The original mass-marketed 2.92 mm connector,
made by Wiltron (now Anritsu). Named the "K"
connector, meaning it covers all of the K
frequency bands.
2.92 mm 40 GHz Air
K 40 GHz Air
thenhan 12/16/2011
N
"Threaded Neill-Concelman" connector, according to
Johnson Components, it is actually a threaded
BNC connector, to reduce vibration problems.
Carl Concelman was an engineer at Amphenol.
TNC 15 GHz PTFE
92. 92
"Gilbert push-on", "Omni-spectra microminiature
push-on"
GPO, OSMP, SMP 40 GHz PTFE
OS-50P 40 GHz Smaller version of OSP blind-mate connector.
2.4 mm, and 1.85 mm will mate with each other
without damage. Developed by Julius Botka and
Paul Watson in 1986, along with the 1.85 mm
connector.
2.4 mm 50 GHz Air
1.85 mm 60 GHz Air Mechanically compatible with 2.4 mm connectors.
Anritsu's term for 1.85 mm connectors because
they span the V frequency band.
The Rolls Royce of connectors. This connector
species works up to 110 GHz. It costs a fortune!
Developed at Hewlett Packard (now Agilent) by
Paul Watson in 1989.
V 60 GHz Air
1 mm 110 GHz Air
thenhan 12/16/2011
109. 109
HỆỆ SỐỐ PHẢẢN XẠẠ
(x) (x) j (x) r i Γ = Γ + Γ
r i Dạng đơn giản Γ = Γ + jΓ
⎧
Γ r
= Re
( Γ
)
⎨ ⎩ Γ i
= Im
( Γ
) thenhan 12/16/2011
110. 110
TRỞỞ KHÁNG ĐĐƯƯỜỜNG DÂY
Z(x) = R(x)+ jX (x)
Z = R + jX
thenhan 12/16/2011
111. 111
TRỞỞ KHÁNG CHUẨẨN HÓA
z(x) = r(x)+ jx
z = r + jx
r = R
0 R
x = X
0 R
Trở kháng đường
dây chuẩn hóa
Điện trở đường dây
chuẩn hóa
Điện kháng đường
dây chuẩn hóa
thenhan 12/16/2011
112. 112
r jx j
+ Γ + Γ
r i
j
− Γ − Γ
r i
+ =
1
1
thenhan 12/16/2011
113. 113
− Γ − Γ
2 2
1
r r i
( )2 2
1
− Γ + Γ
r i
=
2
Γ
x i
( 2 1
− Γ )+ Γ
2 r i
=
thenhan 12/16/2011
114. 114
PHƯƯƠƠNG TRÌNH ĐĐƯƯỜỜNG TRÒN
2
⎞
+ Γ 2
⎟⎠
= 2
⎛
+
r i
r r
1
1
1
⎞
⎟⎠
⎜⎝
⎛
⎜⎝
r
+
Γ −
⎞
⎟⎠
r
⎛
+
⎜⎝
0 ,
1 r
tâm
bán kính
1
1+ r
thenhan 12/16/2011
115. 115
Re(Γ)
Im(Γ)
i Γ
+1
Mặt phẳng phức
r = 0
r = 0.2
r = 0.5
−1 r =1 r = 2
+1
−1
0
r Γ
thenhan 12/16/2011
116. 116
PHƯƯƠƠNG TRÌNH ĐĐƯƯỜỜNG TRÒN
2 2
( )
2 1 1 ⎛ 1 ⎞
⎟⎠
= ⎟⎠
⎜⎝
⎞
Γ − + ⎛Γ −
⎜⎝
x x r i
⎞
⎟⎠
1, 1 tâm
⎛
x
⎜⎝
bán kính
1
x
thenhan 12/16/2011
117. 117
Re(Γ)
Im(Γ)
i Γ
+1
Mặt phẳng phức
x = 0.5 x =1
−1 +1
x = −0.5 x = −1
−1
0
r Γ
thenhan 12/16/2011
118. 118
Re(Γ)
Im(Γ)
i Γ
+1
Mặt phẳng phức
x = 0.5 x =1
−1 +1
x = −1
−1
0
r Γ
x = −0.5
thenhan 12/16/2011
119. 119
Re(Γ)
Im(Γ)
i Γ
+1
Mặt phẳng phức
r = 0
r = 0.2
r = 0.5
−1 r =1 r = 2
+1
−1
0
r Γ
thenhan 12/16/2011
120. 120
Re(Γ)
Im(Γ)
i Γ
+1
Mặt phẳng phức
x = 0.5
x =1
r = 0.2
r = 0.5
−1 +1
r =1 r = 2
x = −1
−1
0
r Γ
x = −0.5
thenhan 12/16/2011