RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
1554901-1 TE Connectivity AMP Connectors	RFI SHIELD FING CU ALLOY AU SLDR	33627
S7131-45R Harwin	RFI SHIELD FINGER AU 2MM SMD	992
SG060100R-48 Leader Tech Inc.	FSG, .060"H X .100"W X 48"L	388
100R375-024000 Orbel	GASKET FABRIC FOAM RECTANGULAR 0	100
WS-3250-KD-2400 3G Shielding Specialties	FAB/FOAM GASKET .250WX.150HX24L	57
4056PA22101800 Laird - Performance Materials	GASKET FAB/FOAM 5.1X457.2MM RECT	0
WS-3275-KD-2400 3G Shielding Specialties	FAB/FOAM GASKET .709WX.562HX24L	96
0077006002 Laird - Performance Materials	FINGERSTOCK BECU 8.1X406.4MM	0
30508 Würth Elektronik Midcom	CONDUCTIVE NI/CU GLASS SLEEVE 1M	296
08-5302-UN Parker Chomerics	METALASTIC EMI GEL 0.03X11.5X22"	4
WS-3645-KB-2400 3G Shielding Specialties	FAB/FOAM GASKET .750WX.400HX24L	94
4791PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 10X457.2MM RECT	0
0C97055902 Laird - Performance Materials	RFI EMI GROUNDING MATERIAL 25FT	0
0097091702 Laird - Performance Materials	S3 STR BF	0
67B5G4004005108R0B Laird - Performance Materials	SP,CON,5,AU,TNR	0
W9908 PulseLarsen Antenna	ANTENNA	0
3031007 Würth Elektronik Midcom	GASKT FABRIC/FOAM 10MMX1M DSHAPE	104
0097095402 Laird - Performance Materials	FINGERSTOCK BECU 11.43X381MM	0
0077012002 Laird - Performance Materials	SLMT STR BF	0
WS-3545-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET 1.000WX.500HX24L	100

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)