Generally, if the position of an object acting as a communication object is changed or if scanning is needed to search for the position of the communication object, a directional pattern of an antenna must be changed.
Conventional art controls the direction of a main beam by changing a phase difference between array radiation elements, or changes a directional pattern using mechanical rotation.
However, according to the conventional art in which the phase difference between array radiation elements is changed, a plurality of additional circuits may be needed to control the phase of each array radiation element, the angle of pattern variation is a small angle, and a high side lobe occurs, resulting in a reduction of radiation efficiency of each antenna.
In addition, according to the conventional art in which the directional pattern changed using mechanical rotation, a separate structure for rotating the antenna is needed. If the communication object moves at high speed, it may be difficult for the directional pattern to be changed in the accurate direction.