Transcript Lee - ECE Users Pages - Georgia Institute of Technology

ECE 6361
Single Balanced Mixer
Vinu Govind
Leekyung(Winnie) Kwon
Todd Lee
Outline
• Project objectives
• Mixer specifications
• Material properties and process
constraints
• Rat-race simulation
• Experimental results
• Conclusions
2
Project Objectives
• Design 2.4 GHz single balanced mixer
using advanced organic material
• Send layout to PRC for fabrication
• Assemble circuit and test
• Compare measurements to simulated
results
3
Mixer Specifications
IF Frequency
IF Bandwidth
RF Frequency
LO Power
LO-RF rejection
LO-IF rejection
Upconverter:
IF Power
Conversion Loss
Downconverter:
RF Power
Conversion Loss
Spurious Response
(as upconverter)
2400-2485 MHz
2485-2900 MHz
2325-2400 MHz
1000-2120 MHz
Specification
140 MHz
5 MHz
2400-2485 MHz
8 dBm (max)
< -20 dB
< -30 dB
Measured Results (Rat-race)
~
~
~
~
-17.3 – -15.8 dB
-18.7 – -16.8 dB
Met Specs?
~
~
~
~
NO
NO
0 dBm (max)
> -9.5 dB
~
Not Measured
~
~
-10 dBm (max)
> -9.5 dB
~
-9.1 – -7.55 dB
~
YES
< -50 dBc
< -40 dBc
< -40 dBc
< -30 dBc
-51.40 dBc
-33.88 dBc
-48.93 dBc
-33.49 dBc
YES
NO
YES
YES
4
Process Details
• 4-metal layer organic MCM-L technology, developed at the
Packaging Research Center (PRC), Georgia Institute of Technology
• 50µ thick APPE© laminate material (εr = 2.85, tan δ = 0.0025)
• 12µ thick copper lines, 0.5mm through-holes
• Size restricted to ~1.5” x ~2.5”
5
Designs Attempted
Marchand Mixer
• Small size, good
simulated
performance
• Performance depends
on amount of
coupling  accurate
overlap control
required
Rat Race Mixer
• Larger size, good
simulated
performance
• Performance depends
on line lengths  no
coupling required
6
Rat Race Balun Schematic
7
Rat Race Mixer Schematic
8
Simulation Results:
Conversion Loss
Conversion Loss:
> -9.5dB
9
Simulation Results:
Isolation
10
Simulation Results: Spurious Signals
IF @ 140 MHz, LO @ 2.26 GHz
LO
LO+IF
LO-IF
11
Rat Race Mixer Layout
12
Measurement Setup:
Conversion Loss
Agilent 8753ES VNA
1
2
RF
Agilent
E4433B
Signal
Generator
R
IF
X
LO
300 MHz
LPF
13
Measurement Setup:
Spurious Signals
HP 8994E Spectrum Analyzer
Agilent
E4433B
Signal
Generator
RF
LO
Agilent
E4433B
Signal
Generator
X
IF
14
Modified Rat Race Mixer
6.6 cm
4.3 cm
15
LO-RF Isolation
16
Modified Mixer Schematic
17
Measured Conversion Loss
18
Measured Isolation
19
Measured Spurious Signals
(as Upconverter)
0 dBm
LO-IF
LO
LO+IF
-20 dBm
-40 dBm
-60 dBm
-80 dBm
1 GHz
20
2.9 GHz
Summary of Rat Race Mixer
LO-RF rejection
LO-IF rejection
Downconverter:
Conversion Loss
Spurious Response
(as upconverter)
2400-2485 MHz
2485-2900 MHz
2325-2400 MHz
1000-2120 MHz
Specification
< -20 dB
< -30 dB
Measured Results (Rat-race)
-17.3 – -15.8 dB
-18.7 – -16.8 dB
Met Specs?
NO
NO
> -9.5 dB
-9.1 – -7.55 dB
YES
< -50 dBc
< -40 dBc
< -40 dBc
< -30 dBc
-51.40 dBc
-33.88 dBc
-48.93 dBc
-33.49 dBc
YES
NO
YES
YES
21
Marchand Mixer
• Area: 7.36 cm2 (26% the size of
the Rat Race mixer)
• Simulations:
Conversion Loss: -9.269 dB
LO-RF Isolation: -27.9 dB
LO-IF Isolation: -33.8 dB
• Measurements:
Conversion Loss: -13 – -12 dB
LO-RF Isolation: -24.8 dB
LO-IF Isolation: -28.1 dB
4.6 cm
1.5 cm
22
Cross Section of Marchand Mixer
Metal 1 (Top Layer)
Layer 2
Overlap = 3.5 mils!
(instead of 7 mils)
23
Conclusions
Design 2.4 GHz single balanced mixer
using advanced organic material
Send layout to PRC for fabrication
Assemble circuit and test
Compare measurements to simulated
results
24
Questions?
25
Comparison of Conversion Losses
26