NON-CONTACTING RADIO COMMUNICATION DEVICE, ADJUSTMENT METHOD OF NON-CONTACTING RADIO COMMUNICATION ANTENNA, AND PORTABLE TERMINAL DEVICE

摘要

PPROBLEM TO BE SOLVED: To facilitate the adjustment of a resonance frequency by enlarging the whole bandwidth (management width) of a resonance frequency of a non-contacting wireless communication antenna. PSOLUTION: An adjusting circuit for adjusting a resonance frequency by changing a resonance capacity of a resonance capacitor which is connected to a non-contacting wireless communication antenna 11, a resonance frequency shift circuit 60 for shifting the resonance frequency to a lower side, and a selecting circuit 63 for performing on/off-control on the resonance frequency shift circuit 60 according to a control state of the adjusting circuit are provided. The selecting circuit 63 performs off-control on the resonance frequency shift circuit 60 if a set value of the adjusting circuit is low, while the selecting circuit performs on-control on the resonance frequency shift circuit 60 if the set value of the adjusting circuit is high. In this way, the upper limit of the resonance frequency which becomes low when the set value of the adjusting circuit is high can be pulled up even in a state that a lower limit of the resonance frequency is set as it is when the set value of the adjusting circuit is low. Then, the management width of the resonance frequency can be made wide and the adjustment of the resonance frequency can be made easy. PCOPYRIGHT: (C)2009,JPO&INPIT