RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
10-05-4308-6502 Parker Chomerics	CHO-SEAL 6502 0.312X0.312" 1'	81
4219PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 13X457.2MM RECT	1009
S1761-46R Harwin	EMI SHIELD FINGER T&R(2000/R)	19950
1447009-8 TE Connectivity AMP Connectors	SHIELDFINGER3525Z	33651
120220-0206 VEAM	UNIVERSAL CONTACT 4MM SMD	109751
0097061002 Laird - Performance Materials	FINGERSTCK BECU ALY 7.57X406.4MM	0
0097031002 Laird - Performance Materials	FINGERSTOCK BECU 12.20X381MM	0
19-05-11440-6502 Parker Chomerics	CHO-SEAL 6502 0.145X0.246" 1'	114
WS-3360-KC-2400 3G Shielding Specialties	FAB/FOAM GASKET .590WX.550HX24L	100
3020608 Würth Elektronik Midcom	GASKET FABRIC/FOAM 8MMX1M RECT	9
37-131-1013-02400 Parker Chomerics	SOFT SHIELD 3700 EMI 1013 24"	919
5401-0009-60-300 Leader Tech Inc.	NI/C FILLED SILICONE; 0.125" DIA	0
4181PA51G01800 Laird - Performance Materials	GASKT FAB/FOAM 10X457.2MM DSHAPE	0
WS-3130-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .125WX.060HX24L	99
2336713-2 TE Connectivity AMP Connectors	SPRING FINGER 1.45H	2261
4912PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 3.8X457.2MM DSHAPE	0
1054390005 Woodhead - Molex	CLIP SPRING ASSY 2.20MM	76106
4198PAH1K01800 Laird - Performance Materials	GSKT FAB/FOAM 10.67X457.2MM CFLD	0
3020706 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	11
4A58PA51H01800 Laird - Performance Materials	GASKT FABRIC/FOAM 6X457.2MM BELL	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)