2. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실2
1. Microwave systems
Transmission
Information
- Channel bandwidth
- Base band
- Inefficient wave radiation
Modulation – center frequency
Time domain Frequency domain
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3. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실3
Why’s modulation need?
Transmission efficiency
- Multiplexing
- Antenna length: wavelength
- Wave radiation: comparison with DC
Battery: DC
Antenna: AC
1. Microwave systems
4. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실4
Microwave transmitter (Tx)
Up-conversion: frequency
( ))cos()cos(
2
1
)cos()cos( yxyxyx −++=
BBf BBLO ff ± BBLO ff ±
1. Microwave systems
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5. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실5
Microwave receiver (Rx)
Down-conversion: frequency
( ))cos()cos(
2
1
)cos()cos( yxyxyx −++=
BBfBBIF ff ±BBLO ff ±
IFLO fff −= IFff =
1. Microwave systems
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6. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실6
Microwave transceiver
Duplexer: bandpass filter or switch
- Loss, tx suppression, channel selection
IF: superheterodyne
No IF: direct conversion
1. Microwave systems
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7. Fundamentals of RF SystemsFundamentals of RF Systems
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FDMA (FDM Access)
1. Microwave systems
Resource: frequency
Guard band
Simple transceiver
Interference
8. Fundamentals of RF SystemsFundamentals of RF Systems
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DS(Direct Sequence)-CDMA
1. Microwave systems
QPSK: Quadrature Phase Shift Keying
9. Fundamentals of RF SystemsFundamentals of RF Systems
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Fundamentals
Antenna gain: anisotropic radiation (G > 1)
isotropic radiation (G = 1)
Directivity and efficiency:
Angular beamwidth: 3dB
Radiation pattern [dBi]: dB isotropic
2. Antennas
DG η=
10. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실10
2. Antennas
Dipole antenna
Simple but long structure
Low efficiency
Microstrip type
11. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실11
Handy phone antenna
Helical antenna
2. Antennas
Complicated structure
Medium efficiency
12. Fundamentals of RF SystemsFundamentals of RF Systems
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Antenna simulation
Ansoft: Ensemble
CST: MWS
Ansoft: HFSS
2. Antennas
13. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실13
Wave propagation
}Re{
}Re{
)cos(),(
)(
tjzjj
o
ztj
o
o
eeeV
eV
ztVtzV
ωβφ
φβω
φβω
−
+−
=
=
+−=
3. Tx line theory
14. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실14
Distributed element
Lumped element: R, L, C
Distributed element: tx line
3. Tx line theory
15. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실15
Wave solution
Traveling wave solution
- Voltage:
- Current:
zz
s eVeVzV γγ −−+
+= 00)(
zz
s eIeIzI γγ −−+
−= 00)(
)())((
)(
2
2
zVCjGLjR
dz
zVd
s
s
ωω ++=
))(( CjGLjRj ωωβαγ ++=+=
3. Tx line theory
16. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실16
Characteristic impedance
Important parameter in tx line:
-
-
CjG
LjR
Z
ω
ω
+
+
=0
−
−
+
+
==
0
0
0
0
0
I
V
I
V
Z
3. Tx line theory
0Z
17. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실17
Reflection coefficient
0
0
0
11 ||
ZZ
ZZ
V
V
e
L
Loj
+
−
==Γ=Γ +
−
φ
Voltage wave continuity conditions
Current wave continuity conditions
3. Tx line theory
18. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실18
Wave power
( ) ( )2
0
2
0*
1
2
Re
2
1
Γ−==
+
Z
V
VIP
3. Tx line theory
19. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실19
SWR (Standing Wave Ratio)
SWR: field theory
VSWR (Voltage SWR): tx line theory
||1
||1
min
max
Γ−
Γ+
=
=
V
V
s
Experiment
3. Tx line theory
20. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실20
Smith chart
Graphical method
Essential diagram for
microwave engineering
P. Smith in 1939
3. Tx line theory
21. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실21
Induction of Smith chart
S-parameter: reflection
coefficient
|S11| = 0: all transmission
|S11| = 1: all reflection
3. Tx line theory
22. Fundamentals of RF SystemsFundamentals of RF Systems
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VNA (Vector Network Analyzer)
Measurement equipment
Reflection coefficients
with frequency sweep
3. Tx line theory
23. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실23
Scattering matrix: Two-port network
Matrix definition: matched load
gain:
isolation:
reflection:,where
21
12
2211
2
1
2221
1211
2
1
S
S
SS
V
V
SS
SS
V
V
=
+
+
−
−
3. Tx line theory
24. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실24
Antenna impedance
Antenna impedance (not infinity) matching
No reflection, power efficiency
Handy phone antenna
3. Tx line theory
25. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실25
Coaxial line
3. Tx line theory
Wide bandwidth (TEM)
Characteristic impedance: 50 Ohms
Shielding
Conductor and dielectric loss
Measurement
RG (Radio Government) series
Coaxial line
26. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실26
Connector
BNC (Bayonet Neill Concelman) connector
SMA (SubMiniature type A) connector
Type N connector
Type K connector
APC (Amphenol Precision Connector)
3. Tx line theory
27. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실27
Microstrip line
3. Tx line theory
Quasi-TEM line
Easy fabrication: etching
Substrate
Characteristic impedance
28. Fundamentals of RF SystemsFundamentals of RF Systems
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Substrate
Relative permittivity
Thickness of a substrate: mil (inch/1000)
Thickness of a metal: oz (almost 1.4 mils)
Loss: loss tangent
Temperature
3. Tx line theory
Power amplifier module
29. Fundamentals of RF SystemsFundamentals of RF Systems
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Etching: PCB (Printed Circuit
Board)
FR4, RT/duroid 5880 (6010 …)
Film
Photoresist (PR)
Toluene
Ultraviolet
Iron chloride
3. Tx line theory
30. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실30
Selection of active device
4. Amplifier
pHEMT amplifier with package
Gain [dB]
Bandwidth [Hz]
Stability: oscillation
Noise figure [dB]: LNA
P1dB [dBm]: PA
Characteristics of
active device: bias
Bare chip
31. Fundamentals of RF SystemsFundamentals of RF Systems
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Wire bonding for bare chip
Wire bonding vs.
soldering
4. Amplifier
32. Fundamentals of RF SystemsFundamentals of RF Systems
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Bias design
Assignment of AC and DC path
4. Amplifier
33. Fundamentals of RF SystemsFundamentals of RF Systems
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S2P file: S-parameter information
Input impedance: S11
Output impedance: S22
Gain: S21
Isolation: S12
4. Amplifier
34. Fundamentals of RF SystemsFundamentals of RF Systems
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Impedance matching
Lumped elements (L or C)
Stub matching
Conjugate matching: maximum power transfer
Noise matching: low noise
( )*
LL ZZ →
4. Amplifier
35. Fundamentals of RF SystemsFundamentals of RF Systems
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Block diagram of cellular phone
LNA (Low Noise Amplifier), PA (Power
Amplifier), Mixer, VCO, switch
Filter, duplexer
4. Amplifier
36. Fundamentals of RF SystemsFundamentals of RF Systems
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Digital RF system
Transmitter and receiver
4. Amplifier
37. Fundamentals of RF SystemsFundamentals of RF Systems
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LNA (Low Noise Amplifier)
Noise figure: 2 dB
Amplifier gain: 15 dB
Return loss: 15 dB
Reverse isolation: 20 dB
Impedance matching: power and noise
4. Amplifier
38. Fundamentals of RF SystemsFundamentals of RF Systems
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SNR: signal to noise ratio
Noiseless system: NF = 1
Noisy system: NF > 1
Ground
Noise figure (NF)
4. Amplifier
in
out
out
in
out
in
N
N
S
S
SNR
SNR
NF ==
39. Fundamentals of RF SystemsFundamentals of RF Systems
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Simulation of LNA
Port
OUT
Num=2
Port
IN
Num=1
C
C2
C=1.0pF
C
C1
C=1.0pF
L
L3
R=
L=1.0nH
L
L2
R=
L=1.0nH
TSMC_CM025RF_PMOS_RF
PMOS_RF1
finger=16
width=10um
length=0.24um
Type=2.5Vtwin-well
TSMC_CM025RF_NMOS
NMOS2
Width=0.30um
Length=0.24um
Type=2.5V_nom
L
L1
R=
L=1.0nH
R
R3
R=50Ohm
R
R2
R=50OhmTSMC_CM025RF_NMOS
NMOS1
Width=0.30um
Length=0.24um
Type=2.5V_nom
R
R1
R=50Ohm
HP
ADS (Advanced Design System)
AC and DC path
4. Amplifier
40. Fundamentals of RF SystemsFundamentals of RF Systems
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HPA (High Power Amplifier)
Output power (P1dB), power gain
Linearity (OIP3)
Efficiency (PAE)
Temperature
Power amplifier scheme
4. Amplifier
41. Fundamentals of RF SystemsFundamentals of RF Systems
전자파연구실전자파연구실41
Characteristics
5. 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