RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
0097093402 Laird - Performance Materials	S3 STR BF	0
4206PA51H01800 Laird - Performance Materials	GASKET FABRIC/FOAM 10X457.2MM SQ	463
3851060 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	50
4569PA01H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 5X457.2MM RECT	0
81-02-14449-2000 Parker Chomerics	FINGERSTOCK 0.12X0.5X16"	27
3020202 Würth Elektronik Midcom	GASKET FABRIC/FOAM 2MMX1M SQ	54
2199248-6 TE Connectivity AMP Connectors	SHIELD FINGER, LOOSE PIECE, TYPE	67017
S7241-45R Harwin	RFI SHIELD FINGER AU 1.3MM SMD	6755
0097097602 Laird - Performance Materials	FINGERSTOCK BECU 7.57X431.8MM	498
WS-3415-KP-2400 3G Shielding Specialties	FAB/FOAM GASKET .200WX.080HX24L	92
4788PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 6.4X457.2MM RECT	0
38401308 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5
10-04-9732-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.156" 1'	42
0077004702 Laird - Performance Materials	GASKET BECU 8.1X13.77MM	0
S7171-45R Harwin	RFI SHIELD FINGER AU 4MM SMD	3063
3021015 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	17
0077009902 Laird - Performance Materials	GASKET BECU 15.24X35MM	0
0077003002 Laird - Performance Materials	GASKET BECU 20.32X18.24MM	0
303076048 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	100
4594PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 8.9X457.2MM RECT	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)