Axial mode helical antenna

• US 4,935,747 A
• Filed: 09/10/1987
• Issued: 06/19/1990
• Est. Priority Date: 09/10/1986
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Kiyokazu, Ieda, Yuichi, Murakami
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): Johnson, Doris J.
• Application Number:
  US07/094,887
• Time in Patent Office: 1,013 Days
• Field of Search: 343/895, 343/775, 343/779, 343/815, 343/816, 343/817, 343/818, 343/819, 343/820, 343/835-838, 343/841
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 11/08 Helical antennas

Abstract

An axial mode helical antenna includes a metal belt member disposed around the reflector of the antenna in order to permit use of reduced diameter reflectors and, therefore, to produce a small helical antenna having increased directivity.

Claims

1. In an axial mode helical antenna having a holder member, a conductor wound around said holder member so as to form a helical antenna element, and a reflector connected to one end of said holder member, an improvement comprising:

a metal belt having first and second ends which is electrically insulated from and disposed substantially around the perimeter of said reflector to permit the use of a small diameter reflector.

2. The improved axial mode helical antenna according to claim 1 wherein the reflector is circular and the center of said metal belt is aligned with the circumference of said reflector.

3. The improved axial mode helical antenna according to claim 1 wherein the reflector is circular and has a diameter of 0.485λ

, λ

being the free space wavelength of the antenna.

4. An axial mode helical antenna comprising:

a holder member;

a conductor wound around said holder member so as to form a helical antenna element;

a reflector connected to one end of said holder member; and

a metal belt having first and second ends which is electrically insulated from and disposed substantially around the perimeter of said reflector to permit the use of a small diameter reflector, the center of said non-looped metal belt being substantially aligned with the perimeter of said reflector.