RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4795PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 12.7X457.2MM REC	482
4742PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 3.8X457.2MM DSHAPE	0
0097055517 Laird - Performance Materials	FINGERSTOCK BECU 8.64X609.6MM	525
0D97098302 Laird - Performance Materials	FINGERSTOCK BECU 2.03X9.53MM	15377
0077009202 Laird - Performance Materials	GASKET BECU 15.24X457.2MM	0
3030202 Würth Elektronik Midcom	GASKET FABRIC/FOAM 2MMX1M DSHAPE	12
8-25FSC-BD-16 Leader Tech Inc.	COPPER BERYLLIUM FINGERSTOCK EMI	0
0077008102 Laird - Performance Materials	GASKET BECU 7.11X609.6MM	474
WS-3170-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .500WX.250HX24L	175
S7071-46R Harwin	RFI SHIELD FINGER TIN 2.5MM SMD	12283
120D150-024000 Orbel	GASKET FABRIC FOAM D SHAPED 0.12	159
S7091-42R Harwin	RFI SHIELD FINGER AU 2.7MM SMD	14871
0097097202 Laird - Performance Materials	FINGERSTOCK BECU 1.6X304.8MM	5324
5411-0001-40-300 Leader Tech Inc.	M83528/011D001, AG/AL FILLED FLO	0
4053PA22101800 Laird - Performance Materials	GSKT FAB/FOAM 2.3X457.2MM DSHAPE	0
4202PA51H01024 Laird - Performance Materials	GSKT FAB/FOAM 10" DSHAPE	49
0077009602 Laird - Performance Materials	GASKET BECU 15.24X27.81MM	0
4096PA51H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 7X457.2MM RECT	0
0077002415 Laird - Performance Materials	GASKET BECU 9.4X12.07MM	0
303064032 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	37

RFI and EMI - Contacts, Fingerstock and Gaskets

1. Overview

RF/IF (Radio Frequency/Intermediate Frequency) and RFID (Radio Frequency Identification) systems require effective electromagnetic interference (EMI) and radio frequency interference (RFI) shielding to maintain signal integrity. Contacts, fingerstock, and gaskets are critical components for ensuring electrical continuity and shielding performance in electronic enclosures. These components prevent electromagnetic leakage while maintaining mechanical functionality in connectors, housings, and assemblies.

2. Main Types and Functional Classification

Type	Functional Features	Application Examples
Contacts	Conductive elements for maintaining electrical connections under compression	RF connectors, PCB grounding pads
Fingerstock	Resilient metal strips with finger-like projections for continuous shielding	Server chassis, military equipment
Gaskets	Conductive elastomers or mesh materials for sealing gaps	Automotive sensors, medical devices

3. Structure and Composition

Typical structures include:

Contacts: Beryllium copper or phosphor bronze cores with conductive platings (gold, silver, nickel)
Fingerstock: Canted coil springs or stamped metal fingers with corrosion-resistant coatings
Gaskets: Silicone rubber with embedded silver-aluminum particles or wire mesh

4. Key Technical Parameters

Parameter	Typical Range	Significance
Contact Resistance	0.1-10 m	Affects signal transmission efficiency
Shielding Effectiveness	60-120 dB (100 MHz-10 GHz)	Determines EMI/RFI attenuation
Compression Force	0.5-5 N/mm	Impacts mechanical durability
Temperature Range	-55 C to +150 C	Defines operational stability

5. Application Fields

Main industries include:

Telecommunications (5G base stations, microwave links)
Automotive (V2X communication systems, radar sensors)
Aerospace (avionics shielding compartments)
Medical (MRI shielding enclosures)

6. Leading Manufacturers and Products

Manufacturer	Representative Products
Parker Chomerics	CHO-SEAL conductive gaskets
Laird Performance Materials	Form-in-Place EMI gaskets
3M	EMI Shielding Tapes 9703/9706
Samtec	RFI/EMI shielded connectors

7. Selection Recommendations

Considerations include:

Frequency range of the application (higher frequencies require tighter tolerances)
Environmental conditions (temperature, humidity, chemical exposure)
Material compatibility (avoid galvanic corrosion between mating surfaces)
Cost-effectiveness (balance performance vs. budget constraints)

Case Study: In automotive radar systems, Parker Chomerics' silicone-based gaskets reduced EMI leakage by 40% compared to traditional metal fingerstock.

8. Industry Trends

Key development directions:

Miniaturization for 5G mmWave applications
Low-PIM (Passive Intermodulation) material formulations
Multi-functional integration with thermal management
RoHS-compliant plating processes (eliminating hexavalent chromium)