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1
Electromagnetic Shielding of Plastic Packaging in Cost-Effective Optical
Transceiver Modules
Wood-Hi Cheng1, Tzong-Lin Wu2, Wern -Shiarng Jou3
1. Institute of Electro-Optical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
2. Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
3. Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan
2
Objective of Study
To develop the plastic optical transceiver modules with low cost and low electromagnetic interference (EMI) for use in Gigabit Ethernet or fiber to the home (FTTH) lightwave communication systems
3
Outline1. Motivation
2. Fabrication and Shielding Performance of Plastic Composites with Discontinuous Carbon Fiber Fillers
3. Fabrication and Shielding Performance of Plastic Composites with Continuous Carbon Fibers
4. Fabrication and Shielding Performance of Hallow Carbon Nanocapules
5. Comparison of Fabrication and Shielding Performance for Plastic Composites and Plastic Optical Transceiver Modules
6. Conclusion
4
Low Cost Laser Module Packages
10
102
103
104
1980 1985 1990 1995 2000 2005
Pric
e (S
.U. d
olla
rs)
PigtailPigtail
connectorized Connectorized
Box-type Box-type Coaxial-type
Coaxial-type
Automated assembly
DIP Butterfly Coaxial: cylindricalBox:
YearTelecom Cooled
Telecom & Datacom Uncooled
5
Transceiver Module Market
>10Gb/s 1%
<2.5Gb/s 9%
<1.25Gb/s 16%
<622Mb/s 7%
<155Mb/s 67%
Source: Fuji Chimera (2002)
6
Optical Transceiver ModuleData Rate :155Mb/s 1.25Gb/s 2.5Gb/s
1X9 Type
1.2 cm
5.7 cm 3.1 cm
Small Form Factor Pluggable (SFP)
55.72mm
13.3 mm
Height = 8.55 mm
8
Techniques for plastic EM shielding
• Conductive sprays • Conductive fillers • Zinc-arc spraying • Electro-plating or electrolysis-plating on housing
surfaces • Modifications of electrical properties during the
molding stage • Metallization processes
9
Conductive fillers for EM shielding
• Metal particles • Metal flakes • Stainless fiber • Graphitized carbon particles • Graphitized carbon fibers • Metal-coated glass • Carbon fibers
10
Fabrication of plastic composites
1.Twin–Screw Extruder
Plastic materials
Carbon fibers
Plastic composites
Injection Molding
Process:
Injection
Fiber Direction
3.specimen2.Injection-Molded Machine
11
Metallographic
LCP (25% Carbon Fiber)
LCP :with 25% carbon fiberorientation uniform
Nylon :with 25% carbon fiberorientation random
13
LCP and Nylon Composites
0
20
40
60
80
0 500 1000 1500Frequency (MHz)
Shie
ldin
g ef
fect
iven
ess (
dB)
LCP (uniform)
Nylon (random)
50 dB 55 dB
1.25GHz155MHz
10dB
45dB
14
Woven Continuous Carbon Fiber Fabrics
Advantages:1. continuous carbon fiber 2. complete conductive networks3. easy fabrication and low cost
Polymer composites Fabrics
15
Fabrication of WCC Fabrics
Different Weave Methods Epoxy
Compression molding machine
Test samples
Plain Balanced Twill Uni-direction
18
Comparison of SE Performance of Nylon, LCP, WCCF and HCNCs Composites
0
10
20
3040
50
60
70
0 1000 2000 3000Frequency(MHz)
Shie
ldin
g E
ffec
tiven
ess(
dB)
Weavon Carbon FiberLCP+20% CFnylon+20% CFHCNCs
21
Comparison of SE performance of realistic housings fabricated by HCNCs composites
0
10
20
30
40
50
0 1000 2000 3000 4000Frequency(MHz)
Shie
ldin
g E
ffec
tive
ness
(dB
)Weavon Carbon FiberLCP CompositeNylon CompositeHCNCs
22
Comparison of cost, and shielding performance of plastic composites
9
4
83
83
Total Weight
( g )
41
0.06
1.91
0.96
0.5
0.5
3
3
Thickness of Sample
(mm)
40~507Carbon
Nanocaplsule( 5.88 )
Epoxy
( 8.8 x 10-3 )
Carbon Nanocaplsule
40~502Carbon Fiber
( 2.3 x 10-2 )
Epoxy
( 8.8 x 10-3 )
Weavon Carbon Fiber
40~5016.6Carbon Fiber
( 2.3 x 10-2 )
LCP
( 2.3 x 10-2 )
LCP Composite
40~5016.6Carbon Fiber
( 2.3 x 10-2 )
Nylon-66
( 8.8 x 10-3 )
Nylon Composite
SE (dB)
Cost of Sample
(US)
Weight of Filler (g)
Filler(Cost/g)
Material(Cost/g)
Sample
23
Measurement setup of the radiated emission for the optical transceiver
module in normal operation
Pattern Generator
Spectrum Analyzer
Signal Analyzer
3m
Shielding Radiation
Fiber
SCSignal
AnalyzerPattern
Generator
Package
Holes(7mm)
24
Comparison of SE performance of optical transceiver modules at 1.25 GHz and 2.5 GHz fabricated by nylon,
LCP, WCCF and HCNCs composites
0
10
20
30
40
0 1 2 3 4Frequcency(GHz)
Shie
ldin
g E
ffec
tive
ness
(dB
)Weavon Carbon FiberLCP CompositeNylon CompositeHCNCs
26
Comparison of cost, and shielding performance of optical transceiver modules
8
2.5
51.5
51.5
Total Weight
( g )
35
0.04
1.18
0.64
0.5
0.5
3
3
Thickness of Sample
(mm)
126Carbon
Nanocaplsule( 5.88 )
Epoxy
( 8.8 x 10-3 )
Carbon Nanocaplsule
241.24Carbon Fiber
( 2.3 x 10-2 )
Epoxy
( 8.8 x 10-3 )
Weavon Carbon Fiber
1712.8Carbon Fiber
( 2.3 x 10-2 )
LCP
( 2.3 x 10-2 )
LCP Composite
1512.8Carbon Fiber
( 2.3 x 10-2 )
Nylon-66
( 8.8 x 10-3 )
Nylon Composite
SE (dB)
Cost of Sample
(US)
Weight of Filler (g)
Filler(Cost/g)
Material(Cost/g)
Sample
27
ConclusionLow-cost optical transceiver modules with transmission rates of 155Mb/s, 1.25Gb/s, and 2.5Gb/s were successfully fabricated to investigate the EM shielding ability.
• The LCP composites perform better SE than the nylon66. This is the LCP polymer chains have higher ordering structure under both melting and solid state.
• By comparison of cost, weight and shielding performance for optical transceiver modules fabricated by the housings of nylon, LCP, WCCF and HCNCs composites, the WCCF composite showed lower cost, lighter weight and higher EM shielding than the other types of composites.
• Due to the fact that the electronic and mechanical properties of HCNCs composites are remarkable, future research and development may push to develop the low cost and low EMI optical transceiver modules using nanoscale HCNCs.
• The packaged plastic optical transceiver modules with low cost and low EMI are suitable for use in Gigabit Ethernet or fiber to the home lightwave (FTTH) communication systems.