RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4208PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 10X457.2MM RECT	162
0077007602 Laird - Performance Materials	GASKET BECU 15.24X8.64MM	0
10-05-4308-S6305 Parker Chomerics	CHO-SEAL S6305 0.312X0.312" 1'	330
WS-3105-KR-2400 3G Shielding Specialties	FAB/FOAM GASKET .197WX0.02H	96
3851080 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	50
0077009402 Laird - Performance Materials	GASKET BECU 9.1X9.88MM	3968
0097055202 Laird - Performance Materials	FINGERSTOCK BECU 3.81X406.4MM	7
67SLH060080070PI00 Laird - Performance Materials	METAL FILM OVER FOAM CONTACTS	318
0077008602 Laird - Performance Materials	GASKET BECU 8.1X406.4MM	0
1551574-5 TE Connectivity AMP Connectors	PRE-LOADED SPRING FINGER 2.6MM	44720
331151722590 Würth Elektronik Midcom	WE-SECF SMT EMI CONTACT FINGER	1000
4609PA22101800 Laird - Performance Materials	GSKT FAB/FOAM 10.16X457.2MM DSHP	0
38401401 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	28
30304031 Würth Elektronik Midcom	GASKET FABRIC/FOAM 4MMX1M DSHAPE	6
3020303 Würth Elektronik Midcom	GASKET FABRIC/FOAM 3MMX1M SQ	17
10-04-1720-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.103" 1'	155
3022104 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	150
24B19-BFA024000T Orbel	FINGER STOCK BECU ADHESIVE MOUNT	88
WS-3355-KC-2400 3G Shielding Specialties	FAB/FOAM GASKET .420WX.465HX24L	90
SMG256197R-0.118 Leader Tech Inc.	SURFACE MOUNT GASKET	855

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)