A wide classification of active defensive mechanisms of various different types, the common nominator of all shielding systems is that they are designed to deflect incoming energy and render it harmless to the user. Different shields are employed to counter different types of energy; these may include radiation of all types, kinetic energy from natural particles or projectile weapons, particle beams, sensor scans, and many other potentially harmful occurances.
Shielding systems, commonly referred to as Shield Generators, are most commonly observed aboard starships, which constantly have to face the harsh environments of space, and may be in danger of coming under attack by some hostile force. Almost all modern starships are equipped with some type of shield, at the very least an anti-particle shield designed to deflect microparticles that might otherwise puncture the hull at fast speeds.
Micro- and macro-scale shields
Shields are also employed on a much larger scale in planetary shields emanated by Shield Bases, which are designed to protect an entire planetary body from harm, as well as on a miniscule scale with personal shields and such devices. While the scale and power levels may vary, the fundamental principle behind shield technology stays the same.
For further information and discussion of various shield types, see Shield technology.