| 摘要 |
PURPOSE:To increase S/N, by increasing the signal level fed to the radio receiver and lowering the signal source impedance viewed from the radio receiver. CONSTITUTION:In mounting the radio receiver of C tuning using varactor diode on a car, taking the radiation impedance of antenna as R1, C1 and cable capacitance as C2, the resonance point between the antenna main body and the power feeding line is selected at the frequency more than the reception band, the inductance L1 is connected in series with the capacitor C1, and the resonant point of the capacitor C1 and the inductance L1 is selected as less than the reception band. Thus, the signal level determined with the dividing ratio of C1/C2 fed to the radio receiver can be increased and the signal source impedance viewed from the radio receiver can be lowered to increase the S/N. |
