| 摘要 |
PURPOSE:To match an FM or AM broadcast receiving antenna with a 300OMEGA feeder, by using linear dipole antennas whose overall length is >=0.5 times as long as the wavelength of an in-use frequency, and connecting a capacitive reactance element for compensation. CONSTITUTION:To linear dipole antennas 6 and 6, a coil (L)7 and a capacitor (C)8 are connected in series at their terminals 9 and 9, and a feeder is also connected. A linear element 10 is arranged symmetrically in parallel to and at distance (d) from the antennas 6 and 6. The overall length of the antennas 6 and 6 is set about 0.55lambda at a 90-108MHz center frequency, and the series resonating circuit of the L7 and C8 has desired capacitive reactance at 90-108MHz; and large inductivity is obtained in a 170-222MHz band. The overall length of the element 10 is set to <=0.5lambda at 196MHz and its distance (d) is 0.033-0.085lambda. Thus, the linear dipole antennas are matched with a feeder having 300OMEGA impedance. |
