RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
3021213 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	84
WS-3135-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .200WX.060HX24L	99
SG250375D-48 Leader Tech Inc.	FSG, .25"H X .375"W X 48"L	114
37-131-1011-02400 Parker Chomerics	SOFT SHIELD 3700 EMI 1011 24"	429
331021483040 Würth Elektronik Midcom	WE-SECF SMT EMI CONTACT FINGER	3770
4375PA51G01800 Laird - Performance Materials	GSKT FAB/FOAM 5.1X457.2MM DSHAPE	173
38401302 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5
WS-3155-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .250WX.125HX24L	92
2108609-5 TE Connectivity AMP Connectors	3.0H SPRING FINGER W/EMBOSS	3122
77-12-3175-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3175 24"	640
77-12-3149-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3149 24"	262
3030303 Würth Elektronik Midcom	GASKET FABRIC/FOAM 3MMX1M DSHAPE	93
07-0202-0488 Parker Chomerics	POLA SPONGE STRIP 11'X0.5X0.093"	25
3020808 Würth Elektronik Midcom	GASKET FABRIC/FOAM 8MMX1M SQ	100
4208PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 10X457.2MM RECT	0
07-0702-9012 Parker Chomerics	POLA SOLID SHEET 36X9X0.125"	0
4283PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 4X457.2MM DSHAPE	425
3021210 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	11
WS-3435-KP-2400 3G Shielding Specialties	FAB/FOAM GASKET .475WX.200HX24L	100
0077005002 Laird - Performance Materials	GASKET BECU 8.1X23.29MM	0

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)