| 摘要 |
<p>With the expansion of communication functions, it is required that mobile terminal devices with communication functions should be equipped with a variety of applications such as a radio, a TV, a wireless LAN, Bluetooth and RFID. Among other things, an AC adapter connected to a mobile terminal device is provided for stable communication or reception. By inserting (connecting) a connector (11) of the AC adapter (10) into the mobile terminal device, an antenna is switched from an internal antenna to an external one that uses parallel wires (A wire (13) and B wire (14)) of a cord (12) of the AC adapter 10. By changing positions of radio frequency cutoff coils (A coil (15) and B coil (16)), it is possible to tune the antenna in response to a target frequency and to secure stable communication or reception.</p> |
