Quadrifilar helix antenna

• US 5,170,176 A
• Filed: 02/25/1991
• Issued: 12/08/1992
• Est. Priority Date: 02/27/1990
• Status: Expired due to Term

• Current Assignee: KDDI Corporation
• Original Assignee: Kokusai Denshi Denwa Company Limited (KDDI Corporation)
• Inventors: Shiokawa, Takayasu, Yasunaga, Masayuki
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): LE, HOANGANH T
• Application Number:
  US07/659,657
• Time in Patent Office: 652 Days
• Field of Search: 343/895, 343/796
• US Class Current: 343/895
• CPC Class Codes: H01Q 11/08 Helical antennas

Abstract

A quadrifilar helix antenna according to the present invention incorporates four helix conductors wound around an axis in the same winding direction. Each of the helix conductors has a linear conductor which is parallel to its axis at either end or both ends of the helix conductor. The present antenna reduces the effect of multipath fading due to sea-surface reflection in mobile satellite communications.

Claims

1. A quadrifilar helix antenna comprising:

a feed circuit located on a z-axis of an xyz rectangular coordinates system;

four feed lines extending from said feed circuit so that said feed lines are perpendicular to one another and are parallel to an xy plane;

four linear conductors each having a top and a bottom end, a top end of each said four linear conductors being connected to a corresponding feed line and positioned such that said linear conductors are parallel to the z-axis, said linear conductors all having the same length; and

four helix conductors each having a first end and a second end so that the first end of each of said four helix conductors is attached to a bottom end of a corresponding linear conductor among said four linear conductors, said four helix conductors being positioned such that center axes of said four helix conductors are defined along the z-axis, said four helix conductors all having the same winding direction, wherein a length of each of said linear conductors is 0.02-0.06 λ

, a pitch length of each of said helix conductors is 0.9-1.1 λ

, a number of turns of a helix of each of said helix conductors is 0.4-0.6 and the radius of the helix is 0.02-0.06 λ

, where λ

is a wavelength, and a corresponding feed line, linear conductor and helix conductor are integral and made from a single wire.

2. A quadrifilar helix antenna according to claim 1, wherein an each second end of said helix conductors is open.

3. A quadrifilar helix antenna according to claim 1, wherein the second ends of said helix conductors are short-circuited to one another by linear conductors.

4. A quadrifilar helix antenna comprising:

a feed circuit located on a z-axis of an xyz rectangular coordinates system;

four conductive feed lines extending from said feed circuit so that said feed lines are perpendicular to one another and are parallel to an xy plane;

four helix conductors having a first end and a second end so that the first end of each of said four helix conductors is attached to one of a corresponding feed line, said four helix conductors being positioned such that center axes of said four helix conductors are all defined along the z-axis, said four helix conductors all having the same winding direction; and

four linear conductors each attached to the second end of a corresponding helix conductor among said four helix conductors so that said linear conductors are parallel to the z-axis, said linear conductors all having the same length.

5. A quadrifilar helix antenna according to claim 4, wherein a length of each of said linear conductors is 0.02-0.06 λ

, a pitch length of each of said helix conductors is 0.9-1.1 λ

, a number of turns of a helix of each of said helix conductor is 0.4-0.6, and the radius of the helix is 0.02-0.06 λ

, where λ

is a wavelength.

6. A quadrifilar helix antenna according to claim 4, wherein the bottom ends of said linear conductors are open.

7. A quadrifilar helix antenna according to claim 4, wherein the bottom ends of said linear conductors are short-circuited to one another by linear conductors.

8. A quadrifilar helix antenna comprising:

a feed circuit located on a z-axis of an xyz rectangular coordinates system;

four feed lines extending from said feed circuit so that those feed lines are perpendicular to one another and are parallel to xy plane;

four first linear conductors each having a top and a bottom end, a top end of each said four linear conductors being connected to a corresponding feed line and positioned such that said linear conductors are parallel to the z-axis, said linear conductors all having the same length;

four helix conductors each having a first end and a second end so that center axes of each helix conductor among said four helix conductors are defined along the z-axis, the bottom end of each of said first linear conductors being connected to the first end of a corresponding helix conductor among the said four helix conductors, said helix conductors all having the same winding direction; and

four second linear conductors, each attached to the second end of a corresponding helix conductor among said four helix conductors and positioned so that said second linear conductors are parallel to the z-axis said four second linear conductors all having the same length.

9. A quadrifilar helix antenna according to claim 8, wherein a length of each of said first linear conductors is 0.02-0.06 λ

, a length of each of said second linear conductors is 0.02-0.06 λ

, a pitch length of each of said helix conductors is 0.9-1.1 λ

, a number of turns of a helix of each of said helix conductor is 0.4-0.6, and the radius of the helix is 0.02-0.06 80 , where λ

is a wavelength.

10. A quadrifilar helix antenna according to claim 8, wherein the bottom ends of said second linear conductors are open.

11. A quadrifilar helix antenna according to claim 8, wherein the bottom ends of said second linear conductors are short-circuited to one another by linear conductors.