RFI and EMI - Contacts, Fingerstock and Gaskets

Part Number	Description / PDF	Quantity
38401107 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	3
0097056802 Laird - Performance Materials	FINGERSTOCK BECU 10.4X406.4MM	0
2199249-3 TE Connectivity AMP Connectors	SHIELD FINGER, LOOSE PIECE, TYPE	1760
38401505 Würth Elektronik Midcom	WE-EGS EMI ELASTOMER GASKET	4
3029040030035 Würth Elektronik Midcom	WE-SMGS SURFACE MOUNT SOLDERABLE	3880
37-131-1030-02400 Parker Chomerics	SOFT SHIELD 3700 EMI 1030 24"	299
5401-0009-40-300 Leader Tech Inc.	M83528/001D009, AG/AL FILLED FLO	4
0097053802 Laird - Performance Materials	GASKET BECU 19.81X609.6MM	0
BMI-C-002 Laird - Performance Materials	CONTACT RETAINER FOR BOARDSHIELD	6941
77-12-3150-02400 Parker Chomerics	SOFT SHIELD 3500 EMI 3150 24"	480
0097095202 Laird - Performance Materials	FINGERSTOCK BECU 15.82X381MM	0
4055PA51G01800 Laird - Performance Materials	RECTANGLE	0
3031210 Würth Elektronik Midcom	WE-LT CONDUCTIVE SHIELDING GASKE	50
3020501 Würth Elektronik Midcom	GASKET FABRIC/FOAM 5MMX1M RECT	141
331011452535 Würth Elektronik Midcom	WE-SECF SMD EMI CONTACT FINGER	565
0097056302 Laird - Performance Materials	FINGERSTOCK BECU 5.33X406.4MM	0
3020502 Würth Elektronik Midcom	GASKET FABRIC/FOAM 5MMX2MMx1M	130
8101010540 Laird - Performance Materials	RFI EMI SHIELDING MATERIAL 1FT	0
07-0701-9012 Parker Chomerics	POLA SOLID SHEET 36X9X0.125"	3
4215PA51G01800 Laird - Performance Materials	RECTANGLE	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)