Antennas
Yagi Antenna (4)
- The length and spacing of the parasitic elements are such that they
reinforce radiation in the direction of the director and reduce it in the
opposite direction. This is how the antenna achieves its gain
over a half wave dipole (see radiation pattern on a previous slide)
- Because of the radiation pattern of Yagi antennas they need
to be rotated in the direction to which a signal is to be transmitted/received
- The maximum theoretical gain of a three element Yagi antenna over
a half wave dipole is about 7dBd (about 5 times).
An important advantage is that the gain also applies to received signals