RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
LT18CJ1921 Laird - Performance Materials	VSLMT,STR,SNB,USFT,CTL 0.11*0.32	145
4212PA51H01200 Laird - Performance Materials	GK NICU PTAFG PU V0 SQ	0
0077008502 Laird - Performance Materials	GASKET BECU 15.24X457.2MM	0
4176PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 20X457.2MM RECT	0
0077005902 Laird - Performance Materials	GASKET BECU 9.4X406.40MM	0
4096PA51G01800 Laird - Performance Materials	GASKT FABRIC/FOAM 7X457.2MM RECT	0
0077004402 Laird - Performance Materials	GASKET BECU 8.1MMX28.04MM	0
0097042402 Laird - Performance Materials	CSTR,FRG,BF	0
8417-3078-62 Laird - Performance Materials	USRE,PU,AGNYLON,PSA,CTL 5.1X6.4X	0
0098055908 Laird - Performance Materials	TWT,STR,SNSAT,USFT,PSA	0
4695PA51G01800 Laird - Performance Materials	GK,NICU,NRSG,PU,V0,SQ	0
0078005417 Laird - Performance Materials	SLMT,9F,SNB,USFT	0
8864-0120-72 Laird - Performance Materials	OSTRHOL,CUSTMATL 7.92X4.89MM	0
4060PA51H01800 Laird - Performance Materials	GASKT FAB/FOAM 12.7X457.2MM DSHP	0
67BCG2505005410R0B Laird - Performance Materials	SP,CON,C,AU,TNR	0
0098060709 Laird - Performance Materials	CSTR,STR,NID,USFT,CLO	0
0077002015 Laird - Performance Materials	SLMT,2F,ZNC	0
8863-0110-12 Laird - Performance Materials	OSTRSD,ECE012 1.57MM	0
67BCG2504002108R00 Laird - Performance Materials	SP,CON,C,AU,TNR	0
0097025502 Laird - Performance Materials	CSTR,FRG,BF	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)