Helical antenna

• US 20040125041A1
• Filed: 10/23/2003
• Published: 07/01/2004
• Est. Priority Date: 04/23/2001
• Status: Active Grant

• Current Assignee: Syntonic Technology, Inc. (Leidos Holdings, Inc.)
• Original Assignee: Syntonic Technology, Inc. (Leidos Holdings, Inc.)
• Inventors: Smith, Mark
• Granted Patent: US 6,940,471 B2
• Time in Patent Office: Days
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/244 extendable from a housing along a given path
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 19/12 wherein the surfaces are concave H01Q19/18 takes precedence
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation

Abstract

This invention relates to antennae and in particular to antennae of the multi-element helically wound type. An helical antenna according to the invention has at least one conductive helix having a vertically orientated central longitudinal axis wherein the helix is fixed at one end and rotatable at the opposite end; a non-conductive constant diameter support means located coaxial with said at least one conductive helix adapted to support said at least one conductive helix; and rotation means attached to said rotatable end of each of said at least one conductive helix arranged to change the pitch of said at least one conductive helix while maintaining the diameter of said at least one conductive helix to affect manipulation of the antenna pattern in gain and azimuth.

Claims

1. An helical antenna comprises

at least one conductive helix having a vertically orientated central longitudinal axis wherein said helix is fixed at one end and rotatable at the opposite end;

a non-conductive constant diameter support means located coaxial with said at least one conductive helix adapted to support said at least one conductive helix;

rotation means attached to said rotatable end of each of said at least one conductive helix arranged to change the pitch of said at least one conductive helix while maintaining the diameter of said at least one conductive helix.

2. An helical antenna according to claim 1 wherein said rotation means comprises a motor with a driven shaft connected to a connecting arm located between the driven shaft and the rotatable end of each of said at least one conductive helix which provides both rotation and vertical translation with respect to said driven shaft while maintaining the diameter of said at least one conductive helix.

11. An helical antenna according to claims 1, 3 or 8 further comprising at least one reflector means located so that said helical antenna lies at the focus of said reflector means such that received and radiated electromagnetic energy is reflected by said reflector means to provide a radiation pattern that changes when said rotation means is operated.

12. An helical antenna according to claim 11 wherein said reflector means has a parabolic shape.

13. An helical antenna according to claims 1, 3 or 8 wherein said at least one non-conductive support means is electrostrictive material the stiffness of which is controllable by the passage of a control current so as to control the diameter of said at least one conductive helix.

14. An helical antenna according to claims 1, 3 or 8 wherein said at least one conductive helix is fed at least two signals at least two points along their length at the same or different frequencies.

15. An array of helical antennae each antenna being according to claims 1, 3 or 8 wherein the base of one antenna is located adjacent the base of another antenna to provide a 360 degree combined transmit and receive antenna pattern.

16. A method of operation of a helical antenna according to claims 1, 3 or 8 including the steps of;

changing the pitch of said at least one conductive helix to one of two extremes

changing the pitch of said at least one conductive helix to the other said extreme so as to control the radiation pattern of said antenna to the available extremes of azimuth in under one second.

3. An helical antenna comprises

at least one conductive helix having a vertically orientated central longitudinal axis wherein said helix is fixed at one end and rotatable at the opposite end;

a non-conductive support means located coaxial with said at least one conductive helix adapted to support said at least one conductive helix;

rotation means attached to said rotatable end of each of said at least one conductive helix arranged to change the pitch of said at least one conductive helix while allowing the diameter of said at least one conductive helix to change.

4. An helical antenna according to claim 3 wherein said rotation means comprises a motor with a driven shaft connected to a connecting arm between the shaft and the rotatable end of each of said at least one conductive helix which provides both rotation and vertical translation with respect to said driven shaft while allowing the diameter of said at least one conductive helix to change.

5. An helical antenna according to claim 3 wherein said shaft is connected to said connecting arm by a screw thread which rotates and translates with respect to said driven shaft along the vertically orientated central longitudinal axis such that rotation to tighten the helix proportionally shortens the length of the helix while allowing the diameter to increase, decrease or remain constant.

6. An helical antenna according to claim 3 wherein said shaft is connected to said connecting arm by a screw thread which rotates and translates with respect to said driven shaft along the vertically orientated central longitudinal axis such that rotation to loosen the helix proportionally lengthens the helix while allowing the diameter to decrease, increase or remain constant.

7. An helical antenna according to claim 3 wherein said shaft is connected to said connecting arm by a screw thread which rotates and translates with respect to said driven shaft along the vertically orientated central longitudinal axis such that rotation to loosen the helix proportionally lengthens the helix while allowing the diameter to increase, decrease or remain constant.

8. An helical antenna comprises

at least one conductive helix having a vertically orientated central longitudinal axis wherein said helix is fixed at one end and rotatable at the opposite end;

a non-conductive constant diameter support means located coaxial with said at least one conductive helix adapted to support said at least one conductive helix;

at least one means to stop rotation of a portion of at least one said conductive helix; and

rotation means attached to said rotatable end of each of said at least one conductive helix arranged to change the pitch of said at least one conductive helix.

9. An helical antenna according to claim 8 further comprising

a non-conductive housing located over said at least one conductive helix;

and

said at least one stop means comprises a shoe attached to at least one conductive helix arranged to engage said housing;

a control means for controlling the engagement of one or more of said at least one stop means to allow the pitch to vary along the length of said at least one helix.

10. An helical antenna according to claim 9 wherein said stop means is adapted so that the pitch and diameter vary along the length of said at least one helix.