The growing complexity of modern electronic and electrical systems, along with the ever increasing distance signals are required to travel, have increased the electrical interference in cables. In order to diminish the effects of signal interference in cables appropriate shielding is vital.
Types of Signal Interferences
The primary function or the shielding is to limit the signal from escaping the wire or cable. Besides, it also prevents external interference or signals from flowing into the wire. Depending on the kind of application, cables can be affected by different types of signal interferences. These include:
- Electrostatic interference
- Electromagnetic interference
- Radio frequency interference
Types of Cable Shielding Popularly Used in the Industry
Mentioned below are the most popular types of cable shielding that are used in the wire and cable industry today:
- Foil Shields: They are generally constructed of a Mylar and aluminum composite tape. They are lightweight, economical, and easy to use. They are normally grounded with a drain wire, and provide 100% shield coverage. Although foil shielding provides good flexibility, it can be damaged in high-flex applications.
- Braid Shields: This is the oldest form of shielding, and is still used in the industry. It is a woven pattern consisting of small gauge wires. Braid shields are mostly made up of bare, tinned, or silver plated copper, and aluminum or steel. They have a typical coverage of 55% to 95%.
- Spiral Shields: This shielding is made up of single strands of wires, which are spirally wrapped around the cable core. This shield is more flexible, and easier to terminate than the woven braid. They have a typical coverage of 95% to 98%. As they are most effective in the audio frequency range, they are typically used in audio and microphone cables.
- Tape Shields: This shielding is made from various types of materials. They normally comprise a laminate of aluminum and polyester layers, which is combined together with an adhesive. These shields are fragile, and offer considerable mechanical strength. Some of the popularly used tape shielding are:
- Bonded Aluminum Polyester
- Aluminum/Polypropylene (AP)
- Aluminum/Polyester/Aluminum (APA)
The cable shielding types mentioned above serve specific applications. Hence, you must consult a manufacturer or supplier to understand which shielding can suit your needs.