Title:
ANTENNA
Document Type and Number:
Japanese Patent JP3489775
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To improve the reception performance of a circularly polarized wave signal by the antenna.
SOLUTION: The antenna used for a frequency of 200MHz or over has a cylindrical ceramic core 12 with a specific dielectric constant of at least 5 and pairs of spiral antenna elements 10A-10D. Each antenna element extends from a supply position at one end of the core 12 and a rim 20U of a conductive sleeve 20 adjacent to the other end of the core 12. The sleeve 20 acts like a trap insulating a ground current flowing to the antenna elements 10A-10D. In order to differentiate the length of the antenna elements, the rim 20U of the sleeve passes through the position shifted from a plane at a right angle to the axis of the core and draws a zigzag path. The antenna elements 10A-10D form simple spirals having nearly balanced radiation resistance.
Inventors:
Oliver Paul Raisten
Application Number:
JP3932497A
Publication Date:
January 26, 2004
Filing Date:
February 24, 1997
Export Citation:
Assignee:
Sarantelle Limited
International Classes:
H01Q1/38; H01Q11/08; H01Q21/24; (IPC1-7): H01Q21/24; H01Q1/38; H01Q11/08
Domestic Patent References:
| JP10504696A |
Other References:
【文献】英国特許出願公開2292257(GB,A)
【文献】米国特許4008479(US,A)
【文献】米国特許4008479(US,A)
Attorney, Agent or Firm:
Tsutomu Toyama (3 others)
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