| 摘要 |
PROBLEM TO BE SOLVED: To provide an antenna device capable of wireless communication without causing a null phenomenon for a plurality of types of corresponding devices having different resonance frequencies, and to provide a portable wireless apparatus provided with the antenna device.SOLUTION: This antenna device performs wireless communications by means of inductive coupling, and includes: a loop antenna; a communication circuit unit which is connected to the loop antenna and for performing wireless communications by means of the inductive coupling; a metal plate disposed in the shape of a loop on the inside or the outside of the loop antenna, with a switch therebetween that can be opened and closed; and a wave detector which detects the level of reception of the wireless signal received by the loop antenna. The communication circuit unit causes the state of the metal plate to be a closed loop state or a non-closed non-loop state by controlling the opening/closing of the switch in response to the level of reception of the wireless signal detected by the wave detector. |
