EMI
CATALOG
www.lairdtech.com
ABOUT LAIRD
Laird is a global technology business focused on enabling wireless
communication and smart systems, and providing components and systems that
protect electronics. Laird operates through two divisions, Wireless Systems and
Performance Materials. Wireless Systems solutions include antenna systems,
embedded wireless modules, telematics products and wireless automation and
control solutions. Performance Materials solutions include electromagnetic
interference shielding, thermal management and signal integrity products.
As a leader in the design, supply and support of innovative technology, our
products allow people, organisations, machines and applications to connect
effectively, helping to build a world where smart technology transforms the
way of life. Custom products are supplied to major sectors of the electronics
industry including the handset, telecommunications, IT, automotive, public
safety, consumer, medical, rail, mining and industrial markets. Providing value
and differentiation to our customers though innovation, reliable fulfilment and
speed, Laird PLC is listed and headquartered in London, and employs over 9,000
people in more than 58 facilities located in 18 countries.
.
TABLE OF CONTENTS
EMI INTRODUCTION
2
EMI SUMMARY
3
BOARD LEVEL SHIELDS
6
Product Selection Guide
6
Introduction
8
Standard Design Shields
9
EZ Peel™
11
Rigid Corner
11
ReCovr™ 12
ReMovl 12
Overview 13
FINGERSTOCK
Product Selection Guide
Introduction
Mounting Methods
Ordering Information
UltraSoft® Series
Recyclable Clean Copper
Slot Mount Series
Dual Slot Series
Teardrop Series
Compact PCI Symmetrical Mount
Alternate Slot Series
Variable Slot Mount
Symmetrical (S3) Slotted Shielding
Solid Top (S3) Symmetrical Slotted Shielding
Clip-On Symmetrical Shielding
No Snag Gasket
All-Purpose Series
Clip-On Series
Low Profile Hook-On Gasket
Low Profile Gasket
Large Enclosure Series
Double-Sided Contact Series
Foldover Series
Stainless Steel I/O Shielding
Flexible Low Compression Series
Clip-On Twist Series
Twist Series
Divider Edge Shielding
Card Guide Clip-On
Clip-On Perpendicular Shielding
Clip-On Perpendicular Grounding Strip
Clip-On Longitudinal Grounding Strip
Mini-Longitudinal Grounding Gasket
Longitudinal Grounding Series
Custom Stamping
Contact Strips / Contact Rings
IEEE 1394 Horizontal Connector Gasket
DIN Connector Series
USB Connector
www.lairdtech.com
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31
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32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
39
39
40
Fiber Optic Shield
40
GBIC Fiber Optic Shield
40
"D" Connector Shielding / Slotted "D"
41
Precision Stamped Metals
42
Contacts 42
Custom Design
44
Metals Galvanic Compatibility Chart
46
VENT PANELS
48
MaxAir™ 49
Elecro-Air™
50
Electrovent™ 51
FABRIC-OVER FOAM
52
Product Selection Guide
52
Introduction
54
EcoGreen™ 56
I/O / Gasket Selection Guide
57
Profile Selection Guide
58
I/O Selection Guide
62
Knitted Conductive Gaskets
65
Visual Part Reference Guide
66
Part Number Cross Reference
67
Ultraflex®
68
All Mesh
69
Elastomer Core
70
Electroground® EMI Washers
72
Electromesh® Tape
75
Conductive Fabric
76
MRI "A" Fabric
77
Conductive Tape
78
ELECTRICALLY CONDUCTIVE ELASTOMERS 79
Introduction 79
Product Selection Guide
80
Case Study
81
Visual Part Reference Guide
85
Electroseal™ Conductive Elastomer
86
Extrusions Guide
87
Gemini™ Coextrusions 93
Fabricated Components Guide
95
Metal Impregnated Materials
99
Specialty Products
102
Automated Form-In-Place Gaskets
103
MICROWAVE ABSORBERS
Product Selection Guide
Design Guide
Q-Zorb® 2000 HF
Q-Zorb® 3000 HP
RFRET 4000
RFLS 5000
Analysis, Test and Prototype Development
105
105
106
109
110
111
112
113
TABLE OF CONTENTS
EMI INTRODUCTION
2
EMI SUMMARY
3
BOARD LEVEL SHIELDS
6
Product Selection Guide
6
Introduction
8
Standard Design Shields
9
EZ Peel™
11
Rigid Corner
11
ReCovr™ 12
ReMovl 12
Overview 13
FINGERSTOCK
Product Selection Guide
Introduction
Mounting Methods
Ordering Information
UltraSoft® Series
Recyclable Clean Copper
Slot Mount Series
Dual Slot Series
Teardrop Series
Compact PCI Symmetrical Mount
Alternate Slot Series
Variable Slot Mount
Symmetrical (S3) Slotted Shielding
Solid Top (S3) Symmetrical Slotted Shielding
Clip-On Symmetrical Shielding
No Snag Gasket
All-Purpose Series
Clip-On Series
Low Profile Hook-On Gasket
Low Profile Gasket
Large Enclosure Series
Double-Sided Contact Series
Foldover Series
Stainless Steel I/O Shielding
Flexible Low Compression Series
Clip-On Twist Series
Twist Series
Divider Edge Shielding
Card Guide Clip-On
Clip-On Perpendicular Shielding
Clip-On Perpendicular Grounding Strip
Clip-On Longitudinal Grounding Strip
Mini-Longitudinal Grounding Gasket
Longitudinal Grounding Series
Custom Stamping
Contact Strips / Contact Rings
IEEE 1394 Horizontal Connector Gasket
DIN Connector Series
USB Connector
www.lairdtech.com
14
14
15
16
17
18
18
19
21
21
22
22
23
24
25
26
27
28
29
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
39
39
40
Fiber Optic Shield
40
GBIC Fiber Optic Shield
40
"D" Connector Shielding / Slotted "D"
41
Precision Stamped Metals
42
Contacts 42
Custom Design
44
Metals Galvanic Compatibility Chart
46
VENT PANELS
48
MaxAir™ 49
Elecro-Air™
50
Electrovent™ 51
FABRIC-OVER FOAM
52
Product Selection Guide
52
Introduction
54
EcoGreen™ 56
I/O / Gasket Selection Guide
57
Profile Selection Guide
58
I/O Selection Guide
62
Knitted Conductive Gaskets
65
Visual Part Reference Guide
66
Part Number Cross Reference
67
Ultraflex®
68
All Mesh
69
Elastomer Core
70
Electroground® EMI Washers
72
Electromesh® Tape
75
Conductive Fabric
76
MRI "A" Fabric
77
Conductive Tape
78
ELECTRICALLY CONDUCTIVE ELASTOMERS 79
Introduction 79
Product Selection Guide
80
Case Study
81
Visual Part Reference Guide
85
Electroseal™ Conductive Elastomer
86
Extrusions Guide
87
Gemini™ Coextrusions 93
Fabricated Components Guide
95
Metal Impregnated Materials
99
Specialty Products
102
Automated Form-In-Place Gaskets
103
MICROWAVE ABSORBERS
Product Selection Guide
Design Guide
Q-Zorb® 2000 HF
Q-Zorb® 3000 HP
RFRET 4000
RFLS 5000
Analysis, Test and Prototype Development
105
105
106
109
110
111
112
113
EMI ESSENTIALS
EMI INTRODUCTION
Overview of EMC/RFI Issues
The phenomenon of electromagnetic interference (EMI) is familiar to virtually everyone, even if they do not
understand the underlying principles. Most people have witnessed firsthand the effects of interference.
To control EMI, government organizations, such as the FCC, CSA, and EEC, mandate that manufacturers may
not design, produce or sell electronic equipment that jams the public broadcast services. In other instances,
however, EMI can constitute more than a mere nuisance. The military and medical communities, for example,
require trouble-free operation of their electronic equipment in adverse electromagnetic environments since
malfunctions could jeopardize missions and personnel. The European Union’s EMC directive also mandates
that “the apparatus has an adequate level of intrinsic immunity to electromagnetic disturbance to enable it
to operate as intended”.
EMC Design of High Speed Systems
The interference and susceptibility (immunity) effects of electronic apparatus are created by time-variant
electromagnetic fields which may be propagated along a conducting medium or by radiation through space.
Because the source of the conducted and radiated interference energy levels may be related, a coordinated
systems design effort is required to reduce these effects.
A design program for an equipment item that must meet both an emission and an immunity requirement
consists of:
• Suppression: Reducing the interference at its source.
• Isolation: Isolating the offending circuits by filtering, grounding and shielding.
• Desensitization: Increasing the immunity of any susceptible circuits.
These three steps should be carried on throughout the entire equipment design and implemented as early
as possible within the design program.
Effects of Logic Speed
The trend in today’s electronic devices is faster, smaller, and digital rather than analog. Most equipment
(95%) of today contains digital circuits. Today’s digital designer must create a circuit board that has the
lowest possible EMI, combined with the highest possible operating/processing speeds. Design of the PCB
is the most critical EMC influencing factor for any system, since virtually all active devices are located on
the board. It is the changing current (accelerated electron movement) produced by the active devices that
result in EMI.
Design Approaches
There are two approaches that can be used to reduce the emission from the PC board. The first approach is
to operate the circuit at the slowest speeds consistent with the functionality of the system, lay out the PCB
with the smallest possible loop areas (especially the high speed devices), and insert suppression components
such as filters, ferrite beads, and bypass capacitors into the circuit to reduce its bandwidth. These techniques
will result in a desired decrease in the high frequency harmonic amplitudes and circuit bandwidth and a
corresponding undesired decrease in both the operating speed and system reliability. The use of slower
speeds with reduced bandwidth will help to desensitize the circuit to external susceptibility fields.
The second is to use shielding. Shielding is the only non-invasive suppression technique. Since the shielding
is not inserted into the circuit, it does not affect the high frequency operating speed of the system, nor does
it affect the operation of the system should changes be made to the design in the future. In addition,
shielding does not create timing problems and waveform distortion; it does not decrease system reliability;
and it reduces crosstalk. Plus, shielding works for both emission suppression as well as susceptibility
(immunity) problems.
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Even with the overall advantages of shielding, the most cost-effective approach is to use a combination
of circuit suppression/hardening and shielding.
www.lairdtech.com
Fabric-Over-Foam and Conductive Foam
Wire Mesh
Tape
Applications
• Shielding or grounding of computer and
telecommunication equipment seams
and apertures
• Covers opened infrequently for servicing
(6-12 times per year)
• Long lasting resiliency is ideal for highly
sensitive components in permanent or
semi-permanent enclosures
• Consistent point-to-point contact for high
shielding effectiveness over the life of the
gasket
• Design flexibility provides grounding and
shielding solutions for I/O shielding panels,
disk drive insulators, ground planes or circuit
boards, electromedical devices, keyboard
devices
• Mask-and-peel tape for painted electronic
enclosures
• Cable and wire harness wrapping
Features and Benefits
Product Highlights
• UL 94VO and HB flame retardant
• Ideal for applications requiring low
pressure force
• Self-terminating cut-to lengths
• High conductivity and shielding attenuation
• Galvanically-compatible with most mating
surfaces
• High abrasion and shear resistance
• Most economical gasket for low-cycling
applications
• High shielding effectiveness over broad
frequency range
• Available in wide variety of sizes and shapes
• Knit construction for long lasting resiliency
• Versatile mounting options
• Available with elastomer gasket for moisture
and dust sealing
• Simple installation
• Ideally suited for thin or low-profile
applications
• Conductive foil tape with release mask for
painted enclosures
• Tin copper cloth and nickel copper cloth
versions provide easy-to-handle alternatives
to foils
Electrical Shielding
Effectiveness
Transfer Impedance (500 MHz)
>85 dB
90 - 105 dB
—
H-field (200 MHz)
Modified Mil 285
30 - 45 dB
55 - 65 dB
—
Plane Wave (2 GHz)
Modified Mil 285
90 - 100 dB
80 - 115 dB
85 - 95 dB
Surface Resistivity