RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
0097062302 Laird - Performance Materials	FINGERSTOCK BECU 10.67X406.4MM	0
0097054002 Laird - Performance Materials	GASKET BECU 7.11X406.4MM	62
3030605 Würth Elektronik Midcom	GASKET FABRIC/FOAM 6MMX1M DSHAPE	46
7125-12502250-71 Leader Tech Inc.	.125" T X 1.250" ID X 2.250" OD	50
3022202 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	0
38401415 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5
3-2199250-4 TE Connectivity AMP Connectors	3.6H SPRNG FINGER TYPE C SMT	0
331141352540 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	3120
3020403 Würth Elektronik Midcom	GASKET FABRIC/FOAM 4MMX1M RECT	62
4919PA51H01800 Laird - Performance Materials	GASKT FAB/FOAM 12.7X457.2MM BELL	0
38401413 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	4
4131PA51G01800 Laird - Performance Materials	GASKT FAB/FOAM 12.7X457.2MM BELL	0
TC-01 Leader Tech Inc.	SMS,TECH CLIP--PCB--SHIELD COVER	115328
4056PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 5.1X457.2MM RECT	36
331051472057 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	912
0097043602 Laird - Performance Materials	FINGERSTOCK BECU 24MMX406.4MM	89
4049PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 6.35X457.2MM SQ	0
S7041-42R Harwin	RFI SHIELD FINGER AU 4MM SMD	59688
07-0701-9006 Parker Chomerics	POLA SOLID SHEET 36X9X0.062"	14
0097063402 Laird - Performance Materials	FINGERSTOCK BECU 15.24X406.4MM	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)