ANSOFT_射频PA仿真设计
- 格式：pdf
- 大小：6.89 MB
- 文档页数：42
Presentation #8
Outline
w w
Introduction Motorola MET Model Design Kit in Ansoft Designer
w
Model consideration and validation
w
Matching Techniques for Power Amplifier Design
w w
Conventional approach to design matching circuits which uses analytical equations to calculate the circuits elements is very time consuming. Smith Tool in Ansoft DesignerTM is a powerful solution to design arbitrary matching networks.
LDMOS MET Model Design Kit
w
MET (Motorola Electro Thermal) Model is available from Ansoft
Nonlinear model for high power RF LDMOS transistor w Calculate both electrical and thermal phenomena
?/8 transformer : any RS -> any ZL
Arbitrary transmission line : any ZS -> any ZL
Transmission Line Matching(2)
w
Shunt C and Series L can be replaced by series low impedance line and series high impedance line respectively.
ΓIN
ΓOUT
Layout view of Ansoft DesignerTM
Schematic for MET Model Validation
w w
Ansoft DesignerTM Circuit Simulator is used to valid MET model. MRF21125 was used.
Vds=28V, Tsnk=25,60,80,100oC
Property
DC I-V setup
Vgs = 4V Vgs = 3.95V
Id [A]
100oC
20oC Low-current region
Vgs [V]
Input Transfer Characteristics
Output Transfer Characteristics
w w
Output power, efficiency, and harmonic contours can plot Max, Min, Step value can be assigned
Lowpass Multi Section Matching
w w w w
Lowpass networks suppress harmonics and improve linearity RF power transistor usually has a small input impedance (RT ≈ 2 or 3) Large ratio of m=R0/RT decrease PA’s bandwidth (R0 is 50ohm) Bandwidth of matching networks can be increased by lowpass multi section
w
w
LDMOS (Laterally Diffused Metal- Oxide- Semiconductor)
wUsed
in making high power, high frequency RF amplifier
/products/hf/ansoft_designer
w
All transistors model include die, package, and bond wire models.
Package model Die mode planes are defined without leads.
Demo Board
MET Model Considerations
w
Capable of performing
w w
Small and Large Signal HB, Noise, and Transient Simulations More accurate because of its ability to simulate self–heating effects
w w w w
Balanced Amplifier Design Doherty and Balanced Amplifier Comparison Conclusion References
Introduction
w
Why a power amplifier is important?
w
Power amplifier is a key element to build a wireless communication system successfully. There is a trade-off between power per cost vs. efficiency and linearity. Digital communications require more peak power for the same bit error rate. To minimize spectral re-growth and interferences, transmitters have to be more linear. Clear modulation scheme requires more higher power and broader bandwidth.
RS+XS
Z0=ZT
RL+ XL
Z0 = (RSRL)1/2
Z0 = (RL2+XL2)1/2 Z0 =
RS(RL2+XL2)-RL(RS2+XS2) RL - RS
RS - RL , ? = tan-1 Z0 RSXL - XSRL
?/4 transformer : any RS -> any RL
Pin [dBm]
Load-pull Analysis Setup
2. Add HB1Tone Analysis
4. Add Load-pull Analysis
1. Add Tone1
3. Create Load-pull Tuner in Port definition
Load-pull Contours
MET Model Validation
w
MRF21125 performances were compared with measurements.
w w
Vds=28V, Idq=1600mA, f = 2120MHz HB1Tone analysis , Linear sweep with Pin
POUT
Gain [dB]
Dotted line : measured Straight line : simulated
Efficiency
Gain
PIN [W]
Efficiency [%]
POUT [dBm]
Matching for Power Amplifier
w w
w
Maximum gain matching based on the small signal S- parameters is not useful to design power amplifier. The information of source and load reflection coefficients as a function of output power is useful to get higher power output. Load-pull Analysis is a method to obtain an optimum power matching point
w
w
w
w
w
What is a solution from Ansoft?
Ansoft DesignerTM
w
Power Amplifier Design
w w w w w w w w w w w
DC network analysis Stability analysis Harmonic balanced analysis Transient analysis Convolution analysis Modulation envelop analysis 3D EM analysis Load-pull analysis Motorola MET model Smith-Tool utility Transmission Line Utility
Series L Z0 >R0 Shunt L Z0=R0 Z0<R0
TRL
Z0 < R0 : Transmission Line Shunt C
R0
Shunt C Series C
Z0 > R0 : Transmission Line Series L
Low Q Matching technique
Outline
w w
Introduction Motorola MET Model Design Kit in Ansoft Designer
w
Model consideration and validation
w
Matching Techniques for Power Amplifier Design
w w
Conventional approach to design matching circuits which uses analytical equations to calculate the circuits elements is very time consuming. Smith Tool in Ansoft DesignerTM is a powerful solution to design arbitrary matching networks.
LDMOS MET Model Design Kit
w
MET (Motorola Electro Thermal) Model is available from Ansoft
Nonlinear model for high power RF LDMOS transistor w Calculate both electrical and thermal phenomena
?/8 transformer : any RS -> any ZL
Arbitrary transmission line : any ZS -> any ZL
Transmission Line Matching(2)
w
Shunt C and Series L can be replaced by series low impedance line and series high impedance line respectively.
ΓIN
ΓOUT
Layout view of Ansoft DesignerTM
Schematic for MET Model Validation
w w
Ansoft DesignerTM Circuit Simulator is used to valid MET model. MRF21125 was used.
Vds=28V, Tsnk=25,60,80,100oC
Property
DC I-V setup
Vgs = 4V Vgs = 3.95V
Id [A]
100oC
20oC Low-current region
Vgs [V]
Input Transfer Characteristics
Output Transfer Characteristics
w w
Output power, efficiency, and harmonic contours can plot Max, Min, Step value can be assigned
Lowpass Multi Section Matching
w w w w
Lowpass networks suppress harmonics and improve linearity RF power transistor usually has a small input impedance (RT ≈ 2 or 3) Large ratio of m=R0/RT decrease PA’s bandwidth (R0 is 50ohm) Bandwidth of matching networks can be increased by lowpass multi section
w
w
LDMOS (Laterally Diffused Metal- Oxide- Semiconductor)
wUsed
in making high power, high frequency RF amplifier
/products/hf/ansoft_designer
w
All transistors model include die, package, and bond wire models.
Package model Die mode planes are defined without leads.
Demo Board
MET Model Considerations
w
Capable of performing
w w
Small and Large Signal HB, Noise, and Transient Simulations More accurate because of its ability to simulate self–heating effects
w w w w
Balanced Amplifier Design Doherty and Balanced Amplifier Comparison Conclusion References
Introduction
w
Why a power amplifier is important?
w
Power amplifier is a key element to build a wireless communication system successfully. There is a trade-off between power per cost vs. efficiency and linearity. Digital communications require more peak power for the same bit error rate. To minimize spectral re-growth and interferences, transmitters have to be more linear. Clear modulation scheme requires more higher power and broader bandwidth.
RS+XS
Z0=ZT
RL+ XL
Z0 = (RSRL)1/2
Z0 = (RL2+XL2)1/2 Z0 =
RS(RL2+XL2)-RL(RS2+XS2) RL - RS
RS - RL , ? = tan-1 Z0 RSXL - XSRL
?/4 transformer : any RS -> any RL
Pin [dBm]
Load-pull Analysis Setup
2. Add HB1Tone Analysis
4. Add Load-pull Analysis
1. Add Tone1
3. Create Load-pull Tuner in Port definition
Load-pull Contours
MET Model Validation
w
MRF21125 performances were compared with measurements.
w w
Vds=28V, Idq=1600mA, f = 2120MHz HB1Tone analysis , Linear sweep with Pin
POUT
Gain [dB]
Dotted line : measured Straight line : simulated
Efficiency
Gain
PIN [W]
Efficiency [%]
POUT [dBm]
Matching for Power Amplifier
w w
w
Maximum gain matching based on the small signal S- parameters is not useful to design power amplifier. The information of source and load reflection coefficients as a function of output power is useful to get higher power output. Load-pull Analysis is a method to obtain an optimum power matching point
w
w
w
w
w
What is a solution from Ansoft?
Ansoft DesignerTM
w
Power Amplifier Design
w w w w w w w w w w w
DC network analysis Stability analysis Harmonic balanced analysis Transient analysis Convolution analysis Modulation envelop analysis 3D EM analysis Load-pull analysis Motorola MET model Smith-Tool utility Transmission Line Utility
Series L Z0 >R0 Shunt L Z0=R0 Z0<R0
TRL
Z0 < R0 : Transmission Line Shunt C
R0
Shunt C Series C
Z0 > R0 : Transmission Line Series L
Low Q Matching technique
