Antenna directivity control system and radio device

A radio device, comprising:

• an antenna directivity control system comprising an antenna including a plurality of antenna elements having mutually different feeding points;
• and
• a controller comprising circuitry configured to control weight for each of the antenna elements,
• wherein each of the antenna elements includes a feed element connected to a respective one of the feeding points, and a radiating element configured to establish electromagnetic field coupling with the feed element such that the radiating element functions as a radiating conductor upon power being fed by establishing the electromagnetic field coupling with the feed element, the circuitry of the controller is configured to control a directivity of the antenna by adjusting an amplitude of a signal at each of the feeding points without controlling a phase of the signal, and each of the antenna elements is formed such that a distance in which the feed element and the radiating element are extended in parallel while separated by a shortest distance is less than or equal to ⅜ of a length of the radiating element.