1. RF Front End Radio Design- Simulations and Specifications
11/13/2018
RF Front End Radio Design- Simulations and Specifications
Hemish Parikh
Advisor: Prof. William R. Michalson

2. RF Front End Receiver Design - Outline
Overview
System parameters
Specifications
System Analysis
System Parameter relations
System Simulations in ADS
Roadmap
Questions
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3. RF Front End Receiver Design - Overview
You are Here
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4. Possible Front End Models
RF Front End Receiver Design - Overview
Possible Front End Models
Model 1: Direct RF Sampling
Today’s Focus
Model 2: Direct Down Conversion
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5. RF Front End Receiver Design – System Parameters
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RF Front End Receiver Design – System Parameters
System Parameters
System Gain (G)
System Noise Figure (NF)
Input 3rd Order Intercept Point (IIP3)
Receiver Sensitivity (Rx-Sens)
Receiver Spurious Free Dynamic Range (SFDR)
Inter Modulation Distortion (IMD)
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6. Component Identification
RF Front End Receiver Design - Specifications
Component Identification
RF MICRO DEVICES
RF-2361
ANALOG DEVICES
AD-8367
COMTELCO
PEXW-400
ANALOG DEVICES
AD-8343
MURATA
MHz
MURATA
0-50 MHz
VECTRON
OSC-1B0-10MHz
VARI-L
VCO T
ANALOG DEVICES
ADF-4112
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7. RF Front End Receiver Design - Specifications
Specifications - LNA
RFMD – 2361
Low Noise Figure (NF): 1.9 dB
Gain (G): 20 dB
Input 3rd order intercept point (IIP3): 6 dBm
Max input RF level: +10 dBm
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8. RF Front End Receiver Design - Specifications
Specifications - AGC
AD 8367:
Variable Gain: dB to 42.5 dB
NF ???
IIP3 ???
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9. Specifications – Mixer (1)
RF Front End Receiver Design - Specifications
Specifications – Mixer (1)
LO-RF
LO+RF
IM Products RF LO
Big role in overall system performance
Mixing is just frequency shifting
Produces LO+RF and LO-RF
Produces Unwanted Inter Modulation Distortion (IMD)
IM products: (M*LO + N*RF) and (M*LO - N*RF)
Good Mixer or a Bad Mixer !!!!!????
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10. Specifications – Mixer (2)
RF Front End Receiver Design - Specifications
Specifications – Mixer (2)
Good Mixer
Low Noise Figure (< 15dB)
High IP3 ( > 15dB)
Good Port Isolation (~ 50dBm)
High Conversion Gain
LO drive level (application dependent)
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11. Specifications – Mixer (3)
RF Front End Receiver Design - Specifications
Specifications – Mixer (3)
AD 8343:
NF: 11 dB
Gain: 7.1 dB
IIP3: 20 dBm
LO drive level: -10 dBm
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12. Specifications – Mixer (4)
RF Front End Receiver Design - Specifications
Specifications – Mixer (4)
LO = 400 MHz
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13. Specifications - TCXO / VCO
RF Front End Receiver Design - Specifications
Specifications - TCXO / VCO
Vectron TCXO:
Frequency: 10 MHz
Stability: 2.5 ppm
Mechanical Trip: /- 3 ppm
Vari-L VCO:
Tuning Range: 400 to 500 MHz
Tuning Sensitivity: 15MHz/V
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14. Specifications – PLL (1)
RF Front End Receiver Design - Specifications
Specifications – PLL (1)
ADF 4113:
Programmable counters: P, B, A, R
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15. RF Front End Receiver Design – Analysis
System Gain
G1= -2dB G2= 20dB G3= 7.1dB G4= -2dB
G(dB) = G1+G2+G3+G4
P_in = G + P_out
BPF
LNA
MIXER
LPF
P_in (dBm)
-40
-42
-22
-14.9
Gain (dB) -2 20
7.1
Cumulative Gain 18
25.1
23.1
P_out (dBm)
-12.9
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16. RF Front End Receiver Design – Analysis
System Noise Figure (1)
Noise Sources
System Noise
Thermal Noise
Noise Figure quantifies how noisy the system is
System noisy due to losses in circuit, solid state devices.
Noise Figure is Noise Factor in dB
GOAL: Design receiver with lowest NF !!!!!!
Reference Max allowed NF: WCDMA: 9 dB Cellular: 10 dB PCS: 6.8 dB
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17. RF Front End Receiver Design – Analysis
System Noise Figure (2)
Critical
G1= -2dB G2= 20dB G3= 7.1dB G4= -2dB
NF1=2dB NF2=1.9dB NF4=11dB NF5= 2dB
Noise Figure of Cascaded System
BPF
LNA
MIXER
LPF
NF (dB) 2
1.9 11
Cumulative NF (dB)
3.9
4.21
4.22
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18. RF Front End Receiver Design – Analysis
System Input IP3 (1)
Problem: Relatively large magnitude and difficult to filter
Third Order products: 2f1+f2, 2f1-f2, 2f2+f1, 2f2-f1, where f1 and f2 are two inputs.
Reference Min allowed IIP3:
Cellular: -13 dBm
PCS: dBm
IP3 is a measure of system linearity.
Point where the desired signal and the 3rd order distortion have equal magnitudes.
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19. RF Front End Receiver Design – Analysis
System Input IP3 (2)
G1= -2dB G2=20dB G3=7.1dB G4= -2dB
Critical
IIP1= dBm IIP2= 6dBm IIP3=20dBm IIP4= dBm
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20. Receiver Sensitivity (1)
RF Front End Receiver Design – Analysis
Receiver Sensitivity (1)
Rx. Sens quantifies the receivers ability to respond to weak signal.
A/D
Input
SNR_min = 12dB (Assume)
BW = 50MHz
Rx. Sens = Noise Floor + 10log(BW) + SNR_min + Noise Figure
Significantly reduces
The Rx. Sens
Rx. Sens =
= dBm
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21. Receiver Sensitivity (2)
RF Front End Receiver Design – Analysis
Receiver Sensitivity (2)
As BW increases, sensitivity becomes poor
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22. Receiver Sensitivity (3)
RF Front End Receiver Design – Analysis
Receiver Sensitivity (3)
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23. Receiver Spurious Free Dynamic Range
RF Front End Receiver Design – Analysis
Receiver Spurious Free Dynamic Range
High DR means Receiver can operate over wide range of input power levels.
Receiver’s Output starts to saturate if the Input is above the range
Below DR, the noise dominates.
SFDR = 0.66 (IIP3 – Rx. Sens)
= 0.66 ( )
= 54.6 dB
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24. RF Front End Receiver Design – Analysis
AGC Issues
Max AGC Gain:
Lowest NF
Lowest IIP3
Min AGC Gain:
High IIP3
High NF
Poor Dynamic Range: 25dB
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25. System Parameters Relations
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RF Front End Receiver Design – Parameters Relations
System Parameters Relations
Higher
IP3
Maximize DR
Maximize
Rx. Sens
Application
Dependent
Minimize NF
Bandwidth
Dependent
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26. ADS simulations for Gain (1)
RF Front End Receiver Design - Simulations
ADS simulations for Gain (1)
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27. ADS simulations for Gain (2)
RF Front End Receiver Design - Simulations
ADS simulations for Gain (2)
Swapped
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28. ADS simulations for NF(1)
RF Front End Receiver Design - Simulations
ADS simulations for NF(1)
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29. ADS simulations for NF(2)
RF Front End Receiver Design - Simulations
ADS simulations for NF(2)
Swapped
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30. ADS simulations for IMD (1)
RF Front End Receiver Design - Simulations
ADS simulations for IMD (1)
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31. ADS simulations for IMD (2)
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RF Front End Receiver Design - Simulations
ADS simulations for IMD (2)
here we want to do this
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32. ADS simulations for IMD (3)
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RF Front End Receiver Design - Simulations
ADS simulations for IMD (3)
here we want to do this
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33. ADS simulations for SFDR
RF Front End Receiver Design - Simulations
ADS simulations for SFDR
Rx Signal Level = -25dBm
SFDR ~= 50 dB
SFDR
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34. RF Front End Receiver Design - Simulations
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35. RF Front End Receiver Design
Roadmap
ADS with Matlab
ADS with Instruments
Set-up Evaluation board
Migrate to 2.4 GHz
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36. RF Front End Receiver Design?
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