director

The term director is used in Fibre Channel and directional antenna technology.

1. Directors are FC switches typically used in backbones of enterprise-wide storage area networks( SAN). They are switching fabrics of the highest availability and high port density. With the directors, components can be hot-swapped during operation. Likewise, they offer fault-free operation with failover. To increase fail-safety, the servers and the storage units are each switched to two ports so that data communication is not interrupted if one port fails. Directors achieve mean time between failures( MTBF) of 99.999%.
2. In antennas, directors are direction-sensitive elements that determine the reception and radiation characteristics ofYagi antennas.
   

   Yagi antenna with multiple directors and reflectors

   The directors are placed at a certain distance in front of the dipole and influence the directivity and antenna gain. The spacing of the directors is calculated from the receive wavelength and is 0.10, 0.15 or 0.20 of the wavelength 'lambda' in front of the dipole. The directors widen towards the dipole. However, they are always narrower - about 5% - than the dipole. Behind the dipole are the reflectors, which increase the return loss. They are about 5% wider than the dipole.