RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4379PA51G01800 Laird - Performance Materials	GSKT FAB/FOAM 14.33X457.2MM BELL	0
67SLH080080080PI00 Laird - Performance Materials	METAL FILM OVER FOAM CONTACTS	721
4295PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 6.4X457.2MM DSHAPE	237
S7121-42R Harwin	RFI SHIELD FINGER AU 1.7MM SMD	39701
4247PA51H01800 Laird - Performance Materials	GASKT FAB/FOAM 17.8X457.2MM RECT	0
WS-3140-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .395WX.060HX24L	100
38401003 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5
WS-3540-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET .750WX.375HX24L	100
WS-3165-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .375WX.250HX24L	200
3021310 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	78
0097055217 Laird - Performance Materials	FINGERSTOCK BECU 3.81X406.4MM	0
30206025 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	0
0077007202 Laird - Performance Materials	GASKET BECU 15.24X411.48MM	0
2306654-3 TE Connectivity AMP Connectors	SPRING FINGER 1.8H	67603
WS-3255-KD-2400 3G Shielding Specialties	FAB/FOAM GASKET .250WX.187HX24L	97
3851130 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	96
10-04-8363-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.103" 1'	171
4619PA51G01800 Laird - Performance Materials	GASKT FABRIC/FOAM 5X457.2MM RECT	606
WS-3160-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .375WX.125HX24L	150
19-04-28067-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.060" 1'	178

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)