Passive radiator

A parasitic element is an active element of an antenna, which is not connected as an active element on the antenna cable to the transmitter or receiver.

In a Yagi -Uda antenna in addition to the active element ( dipole ), a reflector and one or more directors are mounted as a parasitic element to said antenna supporting typically. These are coupled to the active element on, only the electromagnetic waves and enhance the directivity of the dipole in the direction of the directors.

Directors are mechanically shorter and longer than the reflectors fed dipole.