RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4078PA51H01800 Laird - Performance Materials	GSKT FAB/FOAM 9.1X457.2MM DSHAPE	633
WS-3535-KF-2400 3G Shielding Specialties	FAB/FOAM GASKET .750WX.350HX24L	50
4850-12-1212-0300 Parker Chomerics	SOFT SHIELD 4850 12"X12" 3MM	57
3029040030025 Würth Elektronik Midcom	WE-SMGS SURFACE MOUNT SOLDERABLE	4786
30205005 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	146
10-04-2657-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.080" 1'	0
4701PA51H01800 Laird - Performance Materials	GASKET FAB/FOAM 9.5X457.2MM RECT	417
3023002 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	72
30308055 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	28
3030403 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	77
81-02-11818-2000 Parker Chomerics	FINGERSTOCK 0.03X0.23X16"	267
7093-01870750-71 Leader Tech Inc.	.093" T X .187" ID X .750" OD KN	50
S2711-46R Harwin	SMT RFI CLIP 1900/TR (T&R)	87132
4080PA51H01200 Laird - Performance Materials	GK NICU PTAFG PU V0 REC	0
0097060502 Laird - Performance Materials	FINGERSTOCK BECU 9.65X406.4MM	0
77-12-3174-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3174 24"	899
1775073-1 TE Connectivity AMP Connectors	SHIELD FINGER 434025N7	27562
0097061302 Laird - Performance Materials	FINGRSTCK BECU ALY 7.57X406.4MM	494
WS-4515-01-A 3G Shielding Specialties	CONDUCTIVE PE FOAM EMI GASKET	5
38401108 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	5

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)