RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4688PA51H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 3X457.2MM RECT	0
S1741-46R Harwin	RFI SHIELD FINGER TIN 2.5MM SMD	11514
331171302030 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	1245
4633PA51G01800 Laird - Performance Materials	GASKT FAB/FOAM 7.62X457.2MM BELL	0
S1001-46R Harwin	RFI SHIELD CLIP MICRO TIN SMD	87477
67B3G2507009010R0B Laird - Performance Materials	SP,CON,3,AU,TNR	0
19-04-22951-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.070" 1'	46
19-04-27855-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.048" 1'	487
4094PA22101800 Laird - Performance Materials	GASKET FAB/FOAM 4.1X457.2MM RECT	0
WS-3440-KP-2400 3G Shielding Specialties	FAB/FOAM GASKET .500WX.250HX24L	250
1903646-1 TE Connectivity AMP Connectors	SHIELD FINGER 3014 LOW FORCE	184
7062-17601880-71 Leader Tech Inc.	.062" T X 1.760" ID X 1.880" OD	50
SG060125R-48 Leader Tech Inc.	FSG, .060"H X .125"W X 48"L	276
331061603010 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	1389
4520PA22101800 Laird - Performance Materials	GASKET FAB/FOAM 2.03X457.2MM SQ	0
4522PA51G01800 Laird - Performance Materials	GASKET FABRIC/FOAM 4X457.2MM SQ	74
4078PA51G01800 Laird - Performance Materials	GSKT FAB/FOAM 9.1X457.2MM DSHAPE	0
4134PA51G01800 Laird - Performance Materials	GASKT FAB/FOAM 10X457.2MM DSHAPE	0
0097097302 Laird - Performance Materials	CARD GUI CLIPON BECU 3.05X9.53MM	83
38401502 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	4

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)