Microwave Filter
-
Upload
yong-heui-cho -
Category
Technology
-
view
1.118 -
download
2
Embed Size (px)
Transcript of Microwave Filter

Microwave Filter
Microwave EngineeringMicrowave EngineeringCHO, Yong HeuiCHO, Yong Heui

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
2
Circuit Resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
3
Applications
1. LC resonator
Filter Oscillator Frequency meter Tuned amplifier

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
4
LC resonator: ideal resonator
Input impedance
Input power
Resonant frequency: Wm = We
C
jLjZ
in
C
jLjIIZVIP
22
in*
in 2
1
2
1
2
1
LC
1
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
5
Series resonator
R, L, C Input impedance
Input power
Resonant frequency
C
jLjRZ
in
C
jLjRIIZVIP
22
in*
in 2
1
2
1
2
1
LC
1
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
6
Quality factor
Definition
3 dB bandwidth
Q in terms of R, L, C
dloss/seconEnergy
stored energe AverageQ
BW0fQ
RCR
L
P
WQ
l
m
0
00
12
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
7
Perturbation
Input impedance
LjRLjRZ 2
2
20
2
in
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
8
Parallel resonator
R, L, C Input admittance
Input power
Resonant frequency
CjL
j
RY
1in
Cj
L
j
RVVYVIP
1
2
1
2
1
2
1 22*in
*in
LC
1
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
9
Quality factor
Q in terms of R, L, CRC
L
R
P
WQ
l
m0
00
2
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
10
Perturbation
Input admittance
Cj
RCj
RY 2
112
20
2
in
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
11
Loaded Q
Unloaded Q: resonant circuit itself Loaded Q: External load resistor
QQQ eL
111
1. LC resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
12
Short-circuited half-wave line
2. Tx line resonator
Transmission line Input impedance: lossy medium
)tanh()tan(1
)tan()tanh(
tanh
0
0in
llj
ljlZ
ljZZ

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
13
Approximation
Low-loss transmission line
Phase:
ll )tanh(
2/ ,0 l
00
)tan()tan(
l
2. Tx line resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
14
Equivalence
Input impedance
Quality factor
jLR
jlZlj
jlZZ
2
)/(1
)/(
00
0
00in
220
lR
LQ
2. Tx line resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
15
Open-circuited half-wave line
Transmission line Input impedance: lossy medium
)tan()tanh(
)tanh()tan(1
coth
0
0in
ljl
lljZ
ljZZ
2. Tx line resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
16
Approximation
Low-loss transmission line
Phase:
ll )tanh(
2/ ,0 l
00
)tan()tan(
l
2. Tx line resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
17
Equivalence
Input impedance
Quality factor
jCR
jl
Z
jl
ljZZ
2/1
1
)/()/(
)/(1
0
0
0
00in
220 l
RCQ
2. Tx line resonator

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
18
Rectangular waveguide
3. Waveguide cavity
Metallic wall Propagation constant
Resonant condition
22
2
b
n
a
mkmn
ldmn

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
19
Resonant wavenumber
Resonant wavenumber
TE101 mode and TM110 mode Q of cavity
222
d
l
b
n
a
mkmnl
l
e
P
WQ
20
3. Waveguide cavity

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
20
Circular waveguide
Metallic wall Propagation constant Resonant condition
TE111 mode and TM110 mode
ldmn
3. Waveguide cavity

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
21
Dielectric material
4. Dielectric cavity
High Q Fringing field High permittivity: magnetic wall Mechanical tuning TE01 mode Notation
1/2 gL

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
22
5. Mirror
Fabry-Perot resonator
Two mirrors High Q Laser Millimeter and optical applications

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
23
Microwave Filter

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
24
Characteristics
1. Filter
2 port network: S parameters Pass band and stop band Return loss and insertion loss Ripple and selectivity (skirt) Pole and zero Group delay

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
25
Characteristics
1. Filter
Phase response Signal distortion

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
26
Classification
LPF (Low Pass Filter) HPF (High Pass Filter) BPF (Band Pass Filter) BSF (Band Stop Filter): notch filter
1. Filter

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
27
Filter response
Maximally flat (Butterworth) filter Chebyshev filter Elliptic function filter Bessel function filter
1. Filter

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
28
2. Filter design
Design process
Filter specifications Design of low pass filter Scaling and conversion Design of transmission line Implementation

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
29
Insertion loss method
Precise design method Power loss ratio: transducer gain
Reflection coefficient
Results:
2LR)(1
1
load todeliveredPower
source from availablePower
P
)()(
)()(
22
22
NM
M
)(
)(1
2
2
LR
N
MP
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
30
Filter responses: LPF
Maximally flat response
Equal ripple response
Chebyshev polynomial
N
c
kP2
2LR 1
cNTkP
22
LR 1
)cos()(cos nTN
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
31
Example
Design 2-poles low pass filter in terms of the insertion loss method where
1,1 Sc Z
4LR 1 P
2in )(1
)1(
CZ
CZjZLjZ
L
LL
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
32
Impedance scaling
LL
s
ZZZ
ZZ
Z
CC
LZL
0
0
0
0
2in )(1
)1(
CZ
CZjZLjZ
L
LL
R
LQ 0
LC
10
Series RLC resonator
Example
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
33
Frequency scaling for LPF
Basic equation
c
PP LRLR )(
CjCjjB
LjLjjX
c
c
c
c
CC
LL
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
34
Frequency scaling for HPF
Basic equation
cPP LRLR )(
LjCjjB
CjLjjX
c
c
1
1
LC
CL
c
c
1
1
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
35
Frequency scaling for BPF
Basic equation:
12
00
0LRLR Q ,)(
QPP
22
0
0
11
0
0
1
1
LjCjCjQjB
CjLjLjQjX
210
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
36
Frequency scaling for BSF
Basic equation:
12
0
1
0
0LRLR Q ,
1)(
QPP
1
22
1
0
0
1
11
1
0
0
1
1
LC
jCQ
jjB
CL
jLQ
jjX
210
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
37
Example
Design 5-poles low pass filter with a cutoff frequency of 2 [GHz], impedance = 50 [Ohms], insertion loss = 15 dB at 3 [GHz]
618.0
618.1
2
618.1
618.0
5
4
3
2
1
g
g
g
g
g
Maximally flat response
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
38
Richard’s transformation
Transformation
Input impedance: stub
pv
ll
tan)tan(
)tan( ljLLjjX
)tan( ljCCjjB
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
39
LC to stubs
2. Filter design
)tan( ljLLjjX
)tan( ljCCjjB

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
40
Stub characteristics
Resonance: wavelength/8 related to the cutoff frequency
Attenuation pole: wavelength/4
Period: wavelength/2
)tan(1 l
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
41
Kuroda’s identity
Stub transformation: shunt and series stub
Series to shunt stub transform: microstrip line
Implementation
1
21Z
ZN
2. Filter design

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
42
Kuroda’s identity
2. Filter design
Stub transformation

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
43
Equivalent transmission line
2. Filter design
Series to shunt stub transform: microstrip line Implementation: realization

Microwave Microwave EngineeringEngineering
EM Wave EM Wave LabLab
44
Materials
3. Implementation
Microstrip line Dielectric resonator Waveguide Semiconductor MEMS (Micro ElectroMechanical System) LTCC (Low Temperature Cofired Ceramic) SAW (Surface Acoustic Wave) FBAR (Film Bulk Acoustic Resonator) Superconductor