RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
4850-12-1212-0300 Parker Chomerics	SOFT SHIELD 4850 12"X12" 3MM	57
10-04-2657-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.080" 1'	0
81-02-11818-2000 Parker Chomerics	FINGERSTOCK 0.03X0.23X16"	267
77-12-3174-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3174 24"	899
10-04-W204-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.125" 1'	592
19-04-27546-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.062" 1'	471
10-04-8363-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.103" 1'	171
19-04-28067-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.060" 1'	178
10-04-W204-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.125" 1'	0
4850-12-1212-0100 Parker Chomerics	SOFT SHIELD 4850 12"X12" 1MM	0
10-05-6419-6502 Parker Chomerics	CHO-SEAL 6502 0.156X0.156" 1'	80
56-55700 Parker Chomerics	FINGERSTOCK 0.11X0.35X15"	25
10-04-2737-6502 Parker Chomerics	CHO-SEAL 6502 NI/AL 0.250" 1'	83
4850-12-1212-0500 Parker Chomerics	SOFT SHIELD 4850 12"X12" 5MM	32
81-02-14308-2000 Parker Chomerics	FINGERSTOCK 0.22X0.6X16"	249
10-04-2737-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.250" 1'	300
10-04-2657-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.080" 1'	985
10-04-2865-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.093" 1'	284
10-04-8817-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.125" 1'	0
19-04-22951-S6305 Parker Chomerics	CHO-SEAL S6305 NI/C 0.070" 1'	222

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)