Konlida Reveals: The EMI Shielding Materials You Didn't Know About

Electromagnetic shielding is essential to prevent interference from high electric field strength on components. The design principle of electromagnetic shielding involves using a shield to minimize the distributed capacitance between the interference source and the base, thereby reducing the impact of the interference source on the base.

EMI shielding materials are used between heat sources and radiators, eliminating air gaps between them to ensure more even heat dissipation and improve thermal efficiency in electronic devices. Generally, these thermal interface materials must possess good thermal conductivity and surface wettability.

Electromagnetic shielding materials primarily include the following aspects:

1)Conductive Adhesives
Conductive adhesives are adhesives with conductive properties. These adhesives exhibit certain conductive characteristics after curing or drying. Typically composed of base resin and conductive fillers (conductive particles), conductive adhesives create a conductive path through the bonding action of the base resin, enabling the conductive connection of the bonded materials.

Due to the basic resin of conductive adhesives being an adhesive, suitable curing temperatures can be selected for bonding. Additionally, with the rapid development of miniaturized and highly integrated electronic components and printed circuit boards (PCBs), conductive adhesives can be made into pastes, achieving high line resolution. The process is simple and easy to operate, improving production efficiency, making conductive adhesives an ideal choice to replace lead-tin solder for conductive connections.

2)EMI Shielding Materials
These materials primarily include conductive foam, conductive cloth, conductive double-sided tape, copper foil tape, and aluminum foil tape. Below is an overview of each:
❶ Conductive foam
Conductive foam is mainly divided into ordinary conductive foam and omnidirectional conductive foam. It is made of textile fibers with metal plating, wrapped around elastic PU foam, providing good elasticity and conductivity. It is widely used for EMI prevention in various electronic products.

Applications: Suitable for situations where high pressure is not required, providing effective electromagnetic sealing. Examples include electronic shielding enclosures, laptops, mobile communication devices, plasma displays, etc.

❷ Conductive Fabric
Conductive fabric is mainly divided into grid-type conductive fabric and knitted conductive fabric. Grid-type fabric has good conductivity, excellent shielding effects, and is easy to process, making it ideal for wrapping into various regular and irregular conductive foams. It is mainly used for ultra-thin shielding, conductive fabric foam, conductive fabric tape, and conductive fabric gaskets, offering good abrasion resistance. Knitted conductive fabric has excellent abrasion resistance and is easy to punch and form, making it a primary choice for I/O gaskets due to its low cost and ease of wrapping.

Characteristics:

01：Grid-Type Conductive Fabric: Woven fabric type with metal plating (nickel/copper), conductivity < 0.05 ohms/square, easy to form, high shear strength, and abrasion resistance. Surface resistance below < 0.07 ohms/square, shielding effectiveness over 60dB, soft texture, easy to wrap, suitable for ultra-thin shielding, and can withstand 500,000 abrasion cycles (ASTM-D4966).

02：Knitted Conductive Fabric: Conductivity < 0.07 ohms/square, low cost, ideal for I/O foam wrapping, can withstand 400,000 abrasion cycles (ASTM-D4966), easy to form after wrapping.

❸ Copper and Aluminum Foil Conductive Tape

These tapes are made by rolling copper or aluminum into thin sheets. In electronics, their purity is generally above 99%, offering a soft texture, good ductility, and a silver or golden luster. However, they easily oxidize and darken upon contact. Hence, good protective measures are essential during processing.

Applications: Copper and aluminum foil tapes are used for EMI elimination, electromagnetic wave isolation to protect human health, and are applied to computer peripheral cables, computer monitors, and transformer manufacturers.

Uses: Suitable for various transformers, mobile phones, computers, PDAs, PDPs, LCD monitors, laptops, copiers, and other electronic products requiring electromagnetic shielding.

❹Omnidirectional Conductive Foam

This foam consists of a core foam wrapped in conductive fabric, with a vacuum metallized coating throughout the foam. It offers low cost, excellent three-dimensional shielding, and metal-like protective performance.

Characteristics: Excellent shielding, good conductivity, high abrasion resistance, flame retardancy, and thermal conductivity.

Applications: Suitable for shielding various computers, TVs, laptops, card readers, etc.

Applications of Electromagnetic Shielding Materials

Electromagnetic shielding materials are used in communication equipment, network terminals, data transmission, LED, automotive, electronics, consumer electronics, and medical devices.

Suzhou Konlida Precision Electronics Co., Ltd., established in 2006, specializes in the R&D and production of electromagnetic shielding components. We serve industries such as consumer electronics, communications, medical, and automotive, providing OEM services for EMI and EMC components and ODM solutions for electromagnetic shielding design. For inquiries, please contact us by phone, or you can consult/leave a message online to communicate directly with our customer service.