Circularly polarized helix and spiral antennas

• US 3,906,509 A
• Filed: 03/11/1974
• Issued: 09/16/1975
• Est. Priority Date: 03/11/1974
• Status: Expired due to Term

• Current Assignee: Raymond H. Duhamel
• Original Assignee: Raymond H. Duhamel
• Inventors: DuHamel, Raymond H.
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/449,946
• Time in Patent Office: 554 Days
• Field of Search: 343/895
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas

Abstract

An antenna including a support having a conductive outer surface serving to support one or more bays of multifilar helical or spiral conductors with the conductors of each bay fed from the same end and serving to radiate substantially circularly polarized radiation broadside to the antenna.

Claims

1. An elliptically polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same direction, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantially equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being unequally spaced around the support and the feed voltages are given by Vn 3j n M where n 1, 2, ...N N the total number of helically wound conductors M the mode number, an integer, for mode M the phase of the radiated electric field varies with the azimuth angle, phi , as M phi for a constant elevation angle theta , and the magnitude of the electric field is essentially independent of the azimuth angle phi , phi n the angular placement of the nth helically wound conductor about the support, all starting and fed at the same transverse plane.

2. An elliptical polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same directioon, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantiallY equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being unequally spaced around the support and the feed voltages being selected whereby the voltages appearing on the conductors at the same transverse plane are given by Vn ej n M where n 1, 2, ...N N the total number of helically wound conductors M the mode number, an integer, for mode M the phase of the radiated electric field varies with the azimuth angle, phi , as M phi for a constant elevation angle theta , and the magnitude of the electric field is essentially independent of the azimuth angle phi , phi n the angular placement of the nth conductor in said transverse plane.

3. An elliptically polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same direction, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantially equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being uniformly spaced around the support and starting at the same transverse plane and the feed voltages being given by

4. An elliptically polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same direction, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantially equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being equally spaced around the support and the feed voltages being selected whereby the voltages appearing at the same transverse plane are given by

5. An elliptically polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same direction, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantially equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being unequally spaced around the support and the feed voltages being selected wHereby the voltages appearing on the conductors at the same transverse plane are given by Vn ej n M where n 1, 2, ...N N total number of helical conductors M the mode number, an integer, for mode M the phase of the radiated electric field varies with the azimuth angle, phi , as M phi for a constant elevation angle theta , and the magnitude of the electric field is essentially independent of the azimuth angle phi , phi n the angular placement of said transverse plane and wherein the support circumference Beta Rho 1<

M cos 25* - 0.5 Rho 1 radius of the support Beta 2 pi / lambda where lambda is the wavelength.

6. An elliptically polarized helical antenna with low axial ratio comprising a support having a conductive outer surface, at least two conductors spaced from said surface and helically wound about said surface in the same direction, said conductors wound with a pitch angle greater than 25*, means for supporting the helical conductors spaced from said surface, and means for feeding the adjacent end of each of said two or more conductors with voltages of substantially equal magnitude and having predetermined phase relationship whereby to excite said antenna in a selected mode, said helically wound conductors being equally spaced around the support and the exciting voltages being selected whereby the voltages appearing at the same transverse plane are given by

7. A helical antenna as in claim 5 wherein the pitch angle and the turn length of the helical conductors are uniform.

8. A helical antenna as in claim 6 wherein the pitch angle and the turn length of the helical conductors are uniform.

9. A helical antenna as in claim 5 wherein the helical conductors are uniformly spaced from the support.

10. A helical antenna as in claim 6 wherein the helical conductors are uniformly spaced from the support.

11. A helical antenna as in claim 5 wherein the helices are uniformly spaced around the support and the turn length is given by

12. A helical antenna as in claim 6 wherein the turn length is given by

13. A helical antenna as in claim 12 wherein the pitch angle varies along the length of the conductor.

14. A helical antenna as in claim 5 wherein the pitch angle and turn length of the helical conductors are varied in a predetermined manner along the conductors whereby to radiate a predetermined pattern.

15. A helical antenna as in claim 6 wherein the pitch angle and turn length of the helical conductors are varied in a predetermined manner along the conductors whereby to radiate a predetermined pattern.