RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
S0951-46R Harwin	RFI SHIELD CLIP MINI TIN SMD	469883
S1941-46R Harwin	RFI SHIELD FINGER TIN SMD	9968
S7151-45R Harwin	RFI SHIELD FINGER AU 3MM SMD	37837
S7191-45R Harwin	RFI SHIELD FINGER AU 5MM SMD	14362
S1951-46R Harwin	RFI SHIELD FINGER TIN SMD	0
S1741-46R Harwin	RFI SHIELD FINGER TIN 2.5MM SMD	11514
S1001-46R Harwin	RFI SHIELD CLIP MICRO TIN SMD	87477
S0941-46R Harwin	RFI SHIELD CLIP MINI TIN SMD	0
S7051-42R Harwin	RFI SHIELD FINGER AU 6MM SMD	4190
S0981-46R Harwin	RFI SHIELD CLIP R/A TIN SMD	13889
S1411-46R Harwin	RFI SHIELD CLIP MAXI TIN SMD	60042
S7101-42R Harwin	RFI SHIELD FINGER AU 3.5MM SMD	2190
S1721-46R Harwin	RFI SHIELD CLIP MINI TIN SMD	0
S7251-45R Harwin	RFI SHIELD FINGER AU 1.5MM SMD	2534
S7271-45R Harwin	RFI SHIELD FINGER AU 2MM SMD	5137
S7071-46R Harwin	RFI SHIELD FINGER TIN 2.5MM SMD	12283
S7091-42R Harwin	RFI SHIELD FINGER AU 2.7MM SMD	14871
S0971-46R Harwin	RFI SHIELD CLIP MINI TIN SMD	226809
S1761-42R Harwin	RFI SHIELD FINGER GOLD 3.5MM SMD	129178
S0991-46R Harwin	RFI SHIELD CLIP MICRO TIN SMD	340565

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)