RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
WS-3530-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET .707WX.312HX24L	90
3029080080100 Würth Elektronik Midcom	WE-SMGS SURFACE MOUNT SOLDERABLE	852
67B3G2504810010R00 Laird - Performance Materials	SP,CON,AU,TNR 10X2.5X4.8MM	0
WS-3270-KD-2400 3G Shielding Specialties	FAB/FOAM GASKET .500WX.375HX24L	98
0097061102 Laird - Performance Materials	FINGERSTOCK BECU 7.57X406.4MM	408
38401412 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	8
S1951-46R Harwin	RFI SHIELD FINGER TIN SMD	0
0097091802 Laird - Performance Materials	FINGERSTOCK BECU 8.9X381MM	0
10-04-2737-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.250" 1'	300
0077003702 Laird - Performance Materials	GASKET BECU 7.87X37.59MM	0
0097050008 Laird - Performance Materials	GASKET BECU 15.24X609.6MM	0
38401303 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	0
3021508 Würth Elektronik Midcom	GASKET FABRIC/FOAM 15MMX1M RECT	33
4134PA51H01800 Laird - Performance Materials	GASKT FAB/FOAM 10X457.2MM DSHAPE	668
4243PAH1K01800 Laird - Performance Materials	GSKT FAB/FOAM 10.9X 457.2MM CFLD	0
67BCG2003201508R00 Laird - Performance Materials	SP,CON,C,AU,TNR	0
10-04-2657-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.080" 1'	985
0077006502 Laird - Performance Materials	GASKET BECU 8.1X18.54MM	0
4359PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 18X457.2MM RECT	0
30364361 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	32

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)