ANTENNA DEVICE

摘要

A variable-directivity antenna device is manufactured to be thinner and smaller. For example, an antenna device (100) comprises a radiating element (10) and a parasitic element (20), which are parallel to and close to each other. The parasitic element (20) includes a capacitor (22). The parasitic element (20) acts as a reflector when the capacitor (22) is OFF, and acts as a waveguide when the capacitor (22) is ON. The capacitor (22) is switched ON or OFF by a control circuit connected in parallel with the capacitor (22). The control circuit includes a diode (24), a switch (26), and a DC power supply (28). The radiating element (10) and the parasitic element (20) are arranged horizontally.