| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a mechanically robust and electrically stable antenna that is very much smaller than an air-core type antenna. <P>SOLUTION: An antenna for use at UHF or higher has a cylindrical ceramic core (12) having a relative dielectric constant of at least 5. Spiral antenna elements (10A-10D) on the cylindrical surface of the core and connecting radial elements (10AR-10AD) on the end face (12D) of the core, is formed by conductor tracks, plated directly on the core surfaces. On the end face, the elements are connected to an axially located feeder structure in a plated axial passage (14) of the core. The antenna elements are connected together, by a plated sleeve (20) covering a proximal part of the core which, in conjunction with the feeder structure, forms an integral balun for matching to an unbalanced feeder. The ceramic core fills the major part of the interior volume. <P>COPYRIGHT: (C)2007,JPO&INPIT |
