ANTENNA DEVICE AND RADIO COMMUNICATION DEVICE

摘要

It is possible to provide an antenna device and a radio communication device capable of increasing the number of resonances and the bandwidth, improving the antenna efficiency, and performing accurate matching in all the resonance frequencies. The antenna device (1) includes a radiation electrode (2) to which capacity is fed via a capacity unit (C1) and additional radiation electrodes (3-1 to 3-3). The radiation electrode (2) has a tip end (2a) which is grounded to a ground region (402) and becomes a minimum voltage portion during power supply. Moreover, a capacity unit (C2) which becomes a maximum voltage portion during power feed is formed at the base end (2b) of the radiation electrode (2). A grounded variable capacity element (4) is connected in series to the capacity unit (C2). Moreover, the additional radiation electrodes (3-1 to 3-3) are connected to the radiation electrode (2) via switch elements (31 to 33) and have reactance circuits (5-1 to 5-3) in the middle of the connections. The additional radiation electrodes (3-1 to 3-3) have tip ends grounded to the ground region (402).