RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
0077006602 Laird - Performance Materials	FINGERSTOCK BECU 8.1X406.4MM	148
4630PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 4.6X457.2MM BELL	0
3020602 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	698
3029564 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	143
WS-3260-KD-2400 3G Shielding Specialties	FAB/FOAM GASKET .375WX.250HX24L	88
SMG118118R-0.079 Leader Tech Inc.	SURFACE MOUNT GASKET	3175
4051PA51G01800 Laird - Performance Materials	RECTANGLE	0
3020401 Würth Elektronik Midcom	GASKET FABRIC/FOAM 4MMX1M RECT	92
4055PA51H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 8X457.2MM RECT	0
6000-0100-71 Leader Tech Inc.	1.00 X 50' LONG MESH TAPE	14
4B88PA51H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 8X457.2MM BELL	0
0097054202 Laird - Performance Materials	GASKET BECU ALLOY 6.35X406.4MM	415
3851170 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	49
67B5G2504004108R00 Laird - Performance Materials	SP,CON,5,AU,TNR	0
4200PA51G01800 Laird - Performance Materials	RECTANGLE	0
S7271-45R Harwin	RFI SHIELD FINGER AU 2MM SMD	5137
3021307 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	89
3851280 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	50
0077007502 Laird - Performance Materials	GASKET BECU 8.26X406.4MM	0
4789PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 9.5X457.2MM DSHAPE	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)