A Phase-Locked Loop is provided that includes a main loop, a calibration loop, and Control Logic. A fan duct receives the heat sink therein and has an inlet and an outlet at opposite sides thereof. In some instances, a contender monitors the contention channel and withdraws from contention if it detects from the contention channel that a higher priority contender is in contention. The connections to the elements fed from one of the feed lines are rotated with respect to the connections to the elements fed from the other to provide another phase difference between the elements. One or more nematic phase regions are formed along the surface of the liquid crystal film structure within which liquid crystal molecules are oriented along a direction and to a surface depth sufficient to realize one or more phase retardation regions therein having optical axes along the direction of liquid crystal molecule orientation.