| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an antenna device capable of suppressing a level deviation omnidirectionally in a horizontal plane when a collinear antenna is installed at a middle stage of a mounting support. <P>SOLUTION: Three horizontal plane omnidirectional collinear antennas 12a to 12c are allocated at the open angle of 120° substantially perpendicularly at the same height along the outer periphery of a middle stage of a mounting support 11. Pattern adjustment elements 13a to 13c are allocated on the mounting support 11 so that the elements are located at the centers between the respective collinear antennas 12a to 12c. When a 350 MHz band is used and a diameter of the mounting support 11 is about 220 mm, overhang distances L1 of the collinear antennas 12a to 12c are made to be about 0.323 λ and overhang distances L2 of the pattern adjustment elements 13a to 13c are made to be about 0.578 λ. The collinear antennas 12a to 12c are supplied with power in the same phase by equally distributing a signal from a transmitter at a three distributor 15, and the pattern adjustment elements 13a to 13c are made to be parasitic. <P>COPYRIGHT: (C)2013,JPO&INPIT |
