| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a rod antenna for a portable device in which dimensional precision of a cylindrical antenna element is improved, quality stability and yield are improved, a lead time in a manufacture process can be shortened and cost of manufacture can be reduced.SOLUTION: A multistage telescopic rod antenna 10 for a portable device comprises cylindrical antenna elements 21 and 22 each of which is provided in such a manner that the other antenna element freely appears and disappears inside. The cylindrical antenna elements 21 and 22 are formed from seamless pipes which are formed cylindrical by applying drawing press to a metal plate. The cylindrical antenna elements 21 and 22 are formed by applying drawing press to a metal plate in a round plate shape multiple times to form a bottomed cylindrical body, and piercing the center of a bottom of the bottomed cylindrical body to make a bottom radius of the bottomed cylindrical body into a diameter-reduced stopper part.</p> |
