RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
3029100100150 Würth Elektronik Midcom	WE-SMGS SURFACE MOUNT SOLDERABLE	202
BMI-C-001 Laird - Performance Materials	CONTACT BECU 3.1X2.5MM	43533
38401409 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	0
0097060302 Laird - Performance Materials	FINGERSTOCK BECU 9.65X406.4MM	0
6-31CPG-SN-12 Leader Tech Inc.	COPPER BERYLLIUM FINGERSTOCK EMI	0
4046PA51G01800 Laird - Performance Materials	GASKET FABRIC/FOAM 3X457.2MM SQ	0
4094PA51G01800 Laird - Performance Materials	GASKET FAB/FOAM 4.1X457.2MM RECT	0
21118380 Laird - Performance Materials	MF-117 1X12	0
7062-02500500-71 Leader Tech Inc.	.062" T X .250" ID X .500" OD KN	50
331246501860 Würth Elektronik Midcom	WE-SECF SMT EMI CONTACT FINGER	2551
0095091800 Laird - Performance Materials	S3,STR,SS	0
SG187250D-48 Leader Tech Inc.	FSG, .187"H X .25"W X 48"L	344
3851100 Würth Elektronik Midcom	WE-CSGS CONTACT SPRING GASKET	100
4078PA22101800 Laird - Performance Materials	GSKT FAB/FOAM 9.1X457.2MM DSHP	0
0D97098402 Laird - Performance Materials	CGCLIP BF CLO	0
4572AB01K09600 Laird - Performance Materials	GASKET FAB/FOAM 10MMX2.44M RECT	196
SMG118118R-0.118 Leader Tech Inc.	SURFACE MOUNT GASKET	1635
4797PA22101800 Laird - Performance Materials	GSKT FAB/FOAM 11.3X457.2MM KNIFE	149
4112PA51G01800 Laird - Performance Materials	D-SHAPE	55
0077005802 Laird - Performance Materials	GASKET BECU 8.1X23.29MM	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)