How Does a Parabolic Reflector Work?

Satellite dish image by Scrivener from

A variety of electronics, including microphones, satellite television receivers and even flashlights, use parabolic dishes to focus waves and signals. Parabolic dishes are used to gather sound, radio waves, light and other signals.


Parabolic dishes are often used to focus a signal or wave that emanates in several directions from a single source. For example, the light from an open light bulb may be of little use in seeing across a large open field, but placing the same bulb in front of a reflective parabolic dish will direct its light in a single, more useful direction.


Parabola-shape dishes work equally well receiving signals. A naked receiver is only able to capture so much of the light or signal that passes it. A parabolic reflector catches and collects a signal so that it is more concentrated.


When a ray or signal strikes the back of a parabolic dish it is bounced toward a central point called the focus. The sides of the dish are gradually steeper so the reflected rays all reach the focus at the same time. Because the reflected rays reach the focus at once they are amplified without being distorted.