| 摘要 |
PURPOSE:To provide an antenna device which contains such a structure that can switch the resonance frequency of antenna despite the use of a compact antenna that has the comparatively small band width. CONSTITUTION:This antenna device can switch the resonance frequency and includes an antenna main body 11 which has the capacity C1 among a distribution inductance component L1, an impedance adjustment inductance component L2 and a ground potential. Then the capacitor C2 and a diode D1 are connected in series to each other and in parallel to the capacity C1, and the voltage is applied to a connection point 16 between the C2 and the D1 so that the D1 is turned on or off. Thus the resonance frequency is switched by the changeover carried out between the ON and OFF states of the D1. |
