RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
0077001517 Laird - Performance Materials	GASKET BECU 15.24X6.35MM	0
5401-0006-40-300 Leader Tech Inc.	M83528/001D006, AG/AL FILLED FLO	4
4064PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 25.4X457.2MM REC	31
4181PA22101800 Laird - Performance Materials	GASKT FAB/FOAM 10X457.2MM DSHAPE	0
3031010 Würth Elektronik Midcom	GASKT FABRIC/FOAM 10MMX1M DSHAPE	81
S1791-42R Harwin	RFI SHIELD FINGER TIN 4MM SMD	0
1447360-8 TE Connectivity AMP Connectors	SHIELDFINGER1312ATYPE	189683
0097056002 Laird - Performance Materials	FINGERSTOCK BECU 12.7X609.6MM	464
4600PAH1K01800 Laird - Performance Materials	GSKT FAB/FOAM 11.4X457.2MM CFOLD	623
4693PA22101800 Laird - Performance Materials	GASKET FAB/FOAM 4.8X457.2MM RECT	0
67BCG2004705710R00 Laird - Performance Materials	SP,CON,C,AU,TNR	0
4693PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 4.8X457.2MM RECT	399
5411-0001-20-300 Leader Tech Inc.	M83528/011B001, AG/AL FILLED SIL	3
0C97054017 Laird - Performance Materials	RFI EMI GROUNDING MATERIAL 25FT	0
0097062002 Laird - Performance Materials	FINGERSTOCK BECU 11.176X406.4MM	0
080R400-024000 Orbel	GASKET FABRIC FOAM RECTANGULAR 0	200
0077008302 Laird - Performance Materials	GASKET BECU 9.4X406.4MM	0
4164PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 19.1X457.2MM REC	17
0097092102 Laird - Performance Materials	FINGERSTOCK BECU 6.6X609.6MM	0
S7141-45R Harwin	RFI SHIELD FINGER AU 2.5MM SMD	21499

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)