A parabolic antenna is an antenna

Antenna (radio)

An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

 that uses a parabolic reflector

Parabolic reflector

A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis...

, a curved surface with the cross-sectional shape of a parabola

Parabola

In mathematics, the parabola is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface...

, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it is highly directive

Directivity

In electromagnetics, directivity is a figure of merit for an antenna. It measures the power density the antenna radiates in the direction of its strongest emission, versus the power density radiated by an ideal isotropic radiator radiating the same total power.An antenna's directivity is a...

; it functions similarly to a searchlight

Searchlight

A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...

 or flashlight

Flashlight

A flashlight is a hand-held electric-powered light source. Usually the light source is a small incandescent lightbulb or light-emitting diode...

 reflector to direct the radio waves in a narrow beam, or receive radio waves from one particular direction only.