Helical antenna system

• US 20030156072A1
• Filed: 01/25/2002
• Published: 08/21/2003
• Est. Priority Date: 01/25/2001
• Status: Active Grant

• Current Assignee: Skywire Broadband, Inc.
• Original Assignee: Skywire Broadband, Inc.
• Inventors: Gordon, Richard F., Price, Edward G.
• Granted Patent: US 6,867,747 B2
• Time in Patent Office: Days
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 11/08 Helical antennas

Abstract

The invention provides a helical antenna to broadcast a signal from an input line. The antenna includes a base plate and a dielectric rod mounted on the base plate. A conductive helix, surrounds the dielectric rod, and the rod has a pitch angle of at least 12 degrees. A matching network is connected to the conductive helix, to match an impedance of the conductive helix with an impedance of the signal.

Claims

1. A helical antenna to broadcast a signal from an input line, comprising:

a) a base plate;

b) a dielectric rod, mounted on the base plate;

c) a conductive helix, surrounding the dielectric rod, having a pitch angle of at least 12 degrees; and

d) a matching network, connected to the conductive helix, to match an impedance of the conductive helix with an impedance of the input signal.

2. A helical antenna as in claim 1, wherein the dielectric rod is an acetal resin rod.

3. A helical antenna as in claim 1, wherein the base plate is a conductive base plate.

4. A helical antenna as in claim 3, wherein the base plate is a metal base plate.

5. A helical antenna as in claim 3, wherein the base plate includes a plastic layer between the conductive base plate and the matching network.

6. A helical antenna as in claim 1, further comprising a dielectric enclosure attached to the base plate that encloses the antenna, wherein the dielectric enclosure enhances the helical antenna output.

7. A helical antenna to broadcast a signal from an input line, comprising:

a) a conductive base plate;

b) a dielectric rod, mounted on the base plate;

c) a conductive helix, mounted around the dielectric rod, having a pitch angle of at least 12 degrees; and

d) a tapered strip line matching network, connected to the conductive helix to match the impedance of the conductive helix with the impedance of the input line.

8. A helical antenna as in claim 7, wherein the length of the tapered strip line matching network is ¼

of the signal wavelength.

9. A helical antenna as in claim 7, wherein a length of the tapered strip line matching network conforms to the circumference of the dielectric rod.

10. A helical antenna as in claim 7, wherein the tapered strip line matching network provides a flat transmission response over a spectrum of frequencies

11. A helical antenna as in claim 7, wherein the dielectric rod is an acetal resin rod mounted on the base plate.

12. A directional antenna as in claim 13, wherein the acetal resin dielectric rod is Delrin.

13. A directional antenna as in claim 7, wherein the dielectric rod is nylon.

14. A directional antenna as in claim 7, wherein the number of turns of the conductive helix is selected from the group consisting of 5, 10 and 15 turns.

15. A directional antenna to broadcast a signal from an input line, comprising:

a) a conductive base plate;

b) an dielectric rod, mounted on the base plate;

c) a conductive helix, mounted on the dielectric rod, having a pitch angle of at least 12 degrees; and

d) a strip line matching network, attached to the conductive helix, which tapers from the connection point on a coaxial cable to a connection point with the conductive helix, wherein the matching network is configured to match the impedance of the conductive helix with the impedance of the input line.

16. A directional antenna as in claim 15, wherein the length of the strip line matching network is ¼

of signal wavelength.

17. A directional antenna as in claim 15, wherein the strip line matching network conforms to the circumference of the dielectric rod.

18. A directional antenna as in claim 15, wherein the strip line matching network conforms to the circumference of the dielectric rod and forms a triangularly shaped matching network.

19. A directional antenna as in claim 15, wherein the strip line matching network conforms to the circumference of the dielectric rod and forms a crescent shaped matching network.

20. A directional antenna as in claim 15, wherein the strip line matching network tapers along a linear axis to form a matching network.

21. A directional antenna as in claim 15, wherein the strip line matching network tapers from a maximum width of approximately one radius of the dielectric rod down to a width of wire forming the helical antenna.