RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
S1761-46R Harwin	EMI SHIELD FINGER T&R(2000/R)	19950
S1791-42R Harwin	RFI SHIELD FINGER TIN 4MM SMD	0
S7141-45R Harwin	RFI SHIELD FINGER AU 2.5MM SMD	21499
S7261-45R Harwin	RFI SHIELD FINGER AU 1.5MM SMD	7420
S7181-45R Harwin	RFI SHIELD FINGER AU 4.5MM SMD	3999
S7041-42R Harwin	RFI SHIELD FINGER AU 4MM SMD	59688
S0911-46R Harwin	RFI SHIELD CLIP COMPACT TIN SMD	131
S7111-42R Harwin	RFI SHIELD FINGER AU 4.5MM SMD	10792
S0921-46R Harwin	RFI SHIELD CLIP CORNER TIN SMD	1986
S7131-45R Harwin	RFI SHIELD FINGER AU 2MM SMD	992
S7221-45R Harwin	RFI SHIELD FINGER AU 1.23MM SMD	36046
S7161-45R Harwin	RFI SHIELD FINGER AU 3.5MM SMD	2543
S1711-46R Harwin	RFI SHIELD CLIP TIN SMD	8524
S7081-42R Harwin	RFI SHIELD FINGER AU 2.75MM SMD	4123
S7061-42R Harwin	RFI SHIELD FINGER AU 5.5MM SMD	0
S7241-45R Harwin	RFI SHIELD FINGER AU 1.3MM SMD	6755
S7171-45R Harwin	RFI SHIELD FINGER AU 4MM SMD	3063
S2711-46R Harwin	SMT RFI CLIP 1900/TR (T&R)	87132
S0961-46R Harwin	RFI SHIELD CLIP MINI TIN SMD	4990
S7121-42R Harwin	RFI SHIELD FINGER AU 1.7MM SMD	39701

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)