SIGNAL PROCESSING CIRCUIT AND ANTENNA APPARATUS

摘要

To form a signal processing circuit and an antenna apparatus that do not need a circuit for adjusting the resonant frequency of a resonant circuit or resonant-frequency adjustment work and that are downsized. An antenna coil (AL) and a capacitor (CO) form an antenna resonant circuit (AR). An impedance matching circuit composed of capacitors (C1, C2, C3), a first coil (L1), and a second coil (L2) is provided between the antenna resonant circuit (AR) and a wireless IC (11). The first coil (L1) and the second coil (L2) are magnetically coupled.