| 摘要 |
The purpose of the present invention is to implement a compact antenna device that can be shared among a plurality of systems having different frequency bands, and has a good communication characteristic by a simple configuration, and a communication terminal apparatus provided with the antenna device. An antenna device (101) is provided with a radiation element (1) having conductivity, a conductive member (conductor plate (2)), and a first impedance circuit. The first impedance circuit has a first parallel resonance circuit (LC parallel resonance circuit), and is directly connected between the radiation element (1) and the conductive member (conductor plate (2)). Since the first parallel resonance circuit has high impedance and goes into an equivalently open state in the resonance frequency band thereof, one end of the radiation element (1) is opened in the resonance frequency band. In consequence, in the antenna device (101), the radiation element (1) acts as a standing wave antenna that contributes to electric field radiation, and a loop part including the radiation element (1), the conductive member (conductor plate (2)) and the first impedance circuit acts as a magnetic field radiation antenna that contributes to magnetic field radiation. |
