The information terminal unit comprises a transceiver and a processor, while
the variable directional antenna comprises a main antenna element to which the
transceiver directly supplies a radio frequency signal, and a plurality of sub
antenna elements. The sub antenna elements are connected with variable phase shifter
circuits for determining a phase shift amount of a reflecting wave, respectively.
The control circuit receives the directivity data from the CPU of the information
terminal unit and analyzes the received data to control the phase shift amount
of each variable phase shifter circuit. Thereby the phase shift amounts of the
respective sub antenna elements are adjusted so that the wave fronts of the waves
radiated or secondarily radiated from the main antenna element and sub antenna
elements are aligned in a certain direction, and then the variable directional
antenna is controlled so as to have a directivity in that direction.
