RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
5409-0009-60-300 Leader Tech Inc.	NI/C FILLED SILICONE, 0.5" X 0.1	1
1054390002 Woodhead - Molex	CLIP SPRING ASSY 1.42MM	16419
0077008202 Laird - Performance Materials	GASKET BECU 27.94X609.6MM	0
19-05-11440-S6305 Parker Chomerics	CHO-SEAL S6305 0.145X0.246" 1'	167
120220-0310 VEAM	MICRO UNIVERSAL CONTACT Z 1.3MM	36618
4046PA22101800 Laird - Performance Materials	GASKET FABRIC/FOAM 3X457.2MM SQ	114
S7221-45R Harwin	RFI SHIELD FINGER AU 1.23MM SMD	36046
0077006402 Laird - Performance Materials	GASKET BECU 8.1X13.77MM	0
302064064 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	0
1053860003 Woodhead - Molex	ANTI SNAG SPRING CONT 0.25UM GLD	15788
0097065502 Laird - Performance Materials	FINGERSTOCK BECU 1.7X304.8MM	582
4202PA22101800 Laird - Performance Materials	GSKT FAB/FOAM 6.4X457.2MM DSHAPE	0
26B06-BFA018000T Orbel	FINGER STOCK BECU NO SNAG 0.120"	91
SMG236354R-0.315 Leader Tech Inc.	SURFACE MOUNT GASKET	0
0C97055002 Laird - Performance Materials	RFI EMI GROUNDING MATERIAL 25FT	12
S7161-45R Harwin	RFI SHIELD FINGER AU 3.5MM SMD	2543
4286PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 10X457.2MM RECT	0
4584PA51G01800 Laird - Performance Materials	GSKT FAB/FOAM 3.8X457.2MM DSHAPE	0
67B5G2504506010R00 Laird - Performance Materials	SP,CON,5,AU,TNR	0
5409-0004-60-300 Leader Tech Inc.	NI/C FILLED SILICONE; 0.125" X .	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)