| 摘要 |
An antenna element including a loading coil is composed so as to be expanded and contracted like a telescope upward from a housing tube. A characteristic impedance of a transmission line from a lower end part of this antenna element to a cable is equal to one of a cable. A part of the loading coil is reinforced. A branching filter, which is set between the antenna and a communication means using a different frequency band, suppresses a mutual interference between signals of communication means. An antenna circuit, which is set between the antenna or the branching filter and the communication means, converts an impedance of a lower part in a frequency band, and reduces a loss due to a capacitive antenna impedance. |
