RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
5411-0005-60-300 Leader Tech Inc.	NI/C FILLED SILICONE; 0.375" OD,	0
4110HA51H01800 Laird - Performance Materials	D-SHAPE	0
30502 Würth Elektronik Midcom	CONDUCTIVE NI/CU GLASS SLEEVE 1M	125
331161702513 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	826
3030903 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	40
07-0701-9009 Parker Chomerics	POLA SOLID SHEET 36X9X0.094"	7
0097065402 Laird - Performance Materials	FINGERSTOCK BECU 1.6X304.8MM	198
4048PA51G01800 Laird - Performance Materials	SQUARE	0
4C13PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 5X457.2MM DSHAPE	0
37-131-1008-02400 Parker Chomerics	SOFT SHIELD 3700 EMI 1008 24"	196
38401104 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5
WS-3110-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .275WX.020HX24L	69
81-01-14215-2000 Parker Chomerics	FINGERSTOCK 0.13X0.37X16"	47
4520PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 2.03X457.2MM SQ	0
22-S-60AH-BD-16 Leader Tech Inc.	0.22 X 0.60 BD 16--22-S-60AH-BD-	0
19-04-22371-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.043" 1'	182
3021414 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	79
38401410 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	4
38111027 Würth Elektronik Midcom	GASKET FAB/FOAM 11.3MMX1M KNIFE	6
WS-3425-KP-2400 3G Shielding Specialties	FAB/FOAM GASKET .520WX.145HX24L	100

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)