ANTENNA AND WIRELESS IC DEVICE

摘要

Disclosed are an antenna facilitating impedance matching with a wireless IC to reduce deterioration of gain, and a wireless IC device provided with the same. The antenna (101) is provided with a loop electrode (10) that is formed into a loop shape and has two feeding points (11 and 12), and an auxiliary electrode (20) that is electrically connected to the loop electrode (10) and that is formed in a position along the outer periphery of the loop electrode (10). A first end portion of the auxiliary electrode (20) is electrically connected to a vicinity of one feeding point (11) of the loop electrode (10). A second end portion of the auxiliary electrode (20) is open. A resonant circuit is constituted by the auxiliary electrode (20) and the loop electrode (10), and compared to the case in which the antenna is constituted by a single loop electrode (10), impedance of the antenna can be increased, and impedance matching with the wireless IC is facilitated.