RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
5401-0006-20-300 Leader Tech Inc.	M83528/001B006, AG/AL FILLED SIL	0
0077003302 Laird - Performance Materials	GASKET BECU 9.4X406.40MM	0
3020601 Würth Elektronik Midcom	GASKET FABRIC/FOAM 6MMX1M RECT	2
4097PA51G01800 Laird - Performance Materials	KNIFE	0
303038023 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	210
0097022102 Laird - Performance Materials	FINGERSTOCK BECU 3.18X304.8MM	78
0077004902 Laird - Performance Materials	GASKET BECU 15.24X406.4MM	0
0097091102 Laird - Performance Materials	S3 STR BF	0
0077010602 Laird - Performance Materials	FINGERSTOCK BECU 15.24X406.4MM	0
LT18CJ1923 Laird - Performance Materials	SLMT,PCS,SNB,USFT,CTL .110X.320X	100
4184PA51H01800 Laird - Performance Materials	GASKT FAB/FOAM 3.8X457.2MM DSHAP	2450
3020705 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	5
4688PA51G01800 Laird - Performance Materials	GASKT FABRIC/FOAM 3X457.2MM RECT	0
4047PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 12.7X457.2MM REC	0
19-04-25875-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.050" 1'	118
3020702 Würth Elektronik Midcom	GASKET FABRIC/FOAM 7MMX1M RECT	0
4797PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 11.3X457.2MM KNIFE	0
S0991-46R Harwin	RFI SHIELD CLIP MICRO TIN SMD	340565
5409-0006-60-300 Leader Tech Inc.	NI/C FILLED SILICONE; 0.25" X .0	0
WS-3505-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET .340WX.070HX24L	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)