RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
LT18CJ1920 Laird - Performance Materials	VSLMT,STR,SNB,USFT,CTL 0.11*0.32	0
5401-0006-90-300 Leader Tech Inc.	NI/C FILLED SILICONE 25FT ROLL	0
WS-3510-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET .315WX.106HX24L	95
0097061802 Laird - Performance Materials	FINGERSTOCK BECU 10.67X406.4MM	0
1746854-1 TE Connectivity AMP Connectors	SHIELD FINGER	31738
331171302035 Würth Elektronik Midcom	CONTACT FINGER EMI SMD	2257
30512 Würth Elektronik Midcom	CONDUCTIVE NI/CU GLASS SLEEVE 1M	34
55-74000 Parker Chomerics	FINGERSTOCK 0.11X0.32X16.3"	50
4246PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 2.3X457.2MM RECT	1196
0097065517 Laird - Performance Materials	FINGERSTOCK BECU 1.7X304.8MM	199
WS-3445-KP-2400 3G Shielding Specialties	FAB/FOAM GASKET .600WX.250HX24L	100
77-12-3270-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3270 24"	452
38401307 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	2
08-5602-UN Parker Chomerics	METALASTIC EMI GEL .055X11.5X22"	24
4052AC51H00071 Laird - Performance Materials	GASKET FAB/FOAM 2.03X18MM DSHAPE	0
5411-0005-20-300 Leader Tech Inc.	M83528/011B005, AG/AL FILLED SIL	0
3021313 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	88
67SLG050060050PI00 Laird - Performance Materials	METAL FILM OVER FOAM CONTACTS	10763
4694PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 12.7X457.2MM REC	0
120220-0204 VEAM	UNIVERSAL CONTACT 3.5MM SMD	26254

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)