1. RF Front End Radio Design-
Simulations and Specifications
Hemish Parikh
Advisor: Prof. William R. Michalson
2. 9/27/2022 2
Outline
• Overview
• System parameters
• Specifications
• System Analysis
• System Parameter relations
• System Simulations in ADS
• Roadmap
• Questions
RF Front End Receiver Design - Outline
3. 9/27/2022 3
Filters, Amps
Mixers, Osc
Analog Front End Location Estimate
A/D, Latches,
SDRAM
Digital Back End
Vin
GND
Vref
D1
D4
Sign
ENB
Vref
FB
Comp
Reset
I-sense
Drain
Source
Shtdwn
Interface
Overview
RF Front End Receiver Design - Overview
You are Here
4. 9/27/2022 4
Today’s Focus
A/D
AMP
LO
BPF MIXER DSP
LPF
Possible Front End Models
• Model 1: Direct RF Sampling
• Model 2: Direct Down Conversion
A/D
AMP
BPF DSP
880 MHz
RF Front End Receiver Design - Overview
5. 9/27/2022 5
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)
RF Front End Receiver Design – System Parameters
6. 9/27/2022 6
Component Identification
AGC
VCO
BPF MIXER LPF
PLL
TCXO
LNA
0-50 MHz
COMTELCO
PEXW-400
MURATA
415-465 MHz
ANALOG DEVICES
AD-8343
MURATA
0-50 MHz
VARI-L
VCO190-445T
VECTRON
OSC-1B0-10MHz
ANALOG DEVICES
ADF-4112
ANALOG DEVICES
AD-8367
RF MICRO DEVICES
RF-2361
RF Front End Receiver Design - Specifications
7. 9/27/2022 7
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
AGC
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design - Specifications
8. 9/27/2022 8
Specifications - AGC
• AD 8367:
– Variable Gain:
-2.5 dB to 42.5 dB
– NF ???
– IIP3 ???
AGC
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design - Specifications
mV
mV
V
V
dB
Gain
Gain
Gain
950
50
5
50
)
(
9. 9/27/2022 9
Specifications – Mixer (1)
• 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 !!!!!????
RF
LO
LO-RF LO+RF
IM Products
RF Front End Receiver Design - Specifications
10. 9/27/2022 10
Good Mixer
Low Noise Figure
(< 15dB)
Good Port Isolation
(~ 50dBm)
High IP3
( > 15dB)
High Conversion Gain
LO drive level
(application dependent)
RF Front End Receiver Design - Specifications
Specifications – Mixer (2)
11. 9/27/2022 11
• AD 8343:
– NF: 11 dB
– Gain: 7.1 dB
– IIP3: 20 dBm
– LO drive level: -10 dBm
AGC
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design - Specifications
Specifications – Mixer (3)
14. 9/27/2022 14
Specifications – PLL (1)
• ADF 4113:
– Programmable
counters: P, B, A, R
AGC
VCO
MIXER
PLL
TCXO
LNA
R
f
A
B
P
f TCXO
vco /
RF Front End Receiver Design - Specifications
15. 9/27/2022 15
System Gain
G1= -2dB G2= 20dB G3= 7.1dB G4= -2dB
BPF LNA MIXER LPF
P_in (dBm) -40 -42 -22 -14.9
Gain (dB) -2 20 7.1 -2
Cumulative Gain -2 18 25.1 23.1
P_out (dBm) -42 -22 -14.9 -12.9
G(dB) = G1+G2+G3+G4
P_in = G + P_out
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design – Analysis
16. 9/27/2022 16
System Noise Figure (1)
Noise Sources
System Noise Thermal Noise
System noisy due to losses in
circuit, solid state devices.
Noise Figure
quantifies
how noisy the
system is
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
RF Front End Receiver Design – Analysis
18. 9/27/2022 18
System Input IP3 (1)
IP3 is a measure of system linearity.
Point where the desired signal and the 3rd order
distortion have equal magnitudes.
Third Order products:
2f1+f2, 2f1-f2, 2f2+f1, 2f2-
f1, where f1 and f2 are two
inputs.
Problem: Relatively large
magnitude and difficult to
filter
Reference Min allowed IIP3:
Cellular: -13 dBm
PCS: -11.425 dBm
RF Front End Receiver Design – Analysis
23. 9/27/2022 23
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 (1.1 + 80.78)
= 54.6 dB
RF Front End Receiver Design – Analysis
24. 9/27/2022 24
AGC Issues
• Max AGC Gain:
– Lowest NF
– Lowest IIP3
RF Front End Receiver Design – Analysis
• Min AGC Gain:
– High IIP3
– High NF
• Poor Dynamic
Range: 25dB
25. 9/27/2022 25
Dynam ic
Range
dBm
Noise
Figure
Min SNR
Reqd
Approx :
IP3-15
Min Reqd Rx .
Signal Level
Effective Rx. Noise
= -90dBm
Therm al Noise
Floor
System Parameters Relations
Application
Dependent
Maximize
Rx. Sens
Maximize
DR
Higher
IP3
Bandwidth
Dependent
Minimize
NF
RF Front End Receiver Design – Parameters Relations
26. 9/27/2022 26
ADS simulations for Gain (1)
m2
Component=
our_bgain[0::x,0]=22.375
b6
b2_AMP1 b3_MIX1 b5_BPF2
b1_BPF1 b6
0
10
20
-10
30
Component
our_bgain[0::x,0]
m2
Gain in the Receive RF chain
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design - Simulations
27. 9/27/2022 27
ADS simulations for Gain (2)
m1
Component=
our_bgain[0::x,0]=22.018
b6
b2_BPF1 b3_MIX1 b5_BPF2
b1_AMP1 b6
0
10
20
-10
30
Component
our_bgain[0::x,0]
m1
Gain in the Receive RF chain
MIXER
BPF LPF
LNA
P_in P_out
Swapped
RF Front End Receiver Design - Simulations
28. 9/27/2022 28
ADS simulations for NF(1)
m1
Component=
our_bnf[0::x,0]=4.259
b6
b2_AMP1 b3_MIX1 b5_BPF2
b1_BPF1 b6
1
2
3
4
0
5
Component
our_bnf[0::x,0]
m1
NF in the Receive RF chain
BPF MIXER LPF
LNA
P_in P_out
RF Front End Receiver Design - Simulations
29. 9/27/2022 29
ADS simulations for NF(2)
MIXER
BPF LPF
LNA
P_in P_out
Swapped
m5
Component=
our_bnf[0::x,0]=2.468
b6
b2_BPF1 b3_MIX1 b5_BPF2
b1_AMP1 b6
0.5
1.0
1.5
2.0
0.0
2.5
Component
our_bnf[0::x,0]
m5
NF in the Receive RF chain
RF Front End Receiver Design - Simulations
