Quadrifilar helix antenna and feed network

• US 5,793,338 A
• Filed: 08/09/1995
• Issued: 08/11/1998
• Est. Priority Date: 08/09/1995
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Thompson, James H., Standke, Randolph E.
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): PHAN, THO GIA
• Application Number:
  US08/513,317
• Time in Patent Office: 1,098 Days
• Field of Search: 343/895, 343/859
• US Class Current: 343/895
• CPC Class Codes: H01Q 11/08 Helical antennas

Abstract

A quadrifilar antenna is comprised of four radiators which, in the preferred embodiment, are etched onto a radiator portion of a microstrip substrate. The microstrip substrate is formed into a cylindrical shape such that the radiators are helically wound. Also etched onto the microstrip substrate is a feed network that provides 0°, 90°, 180° and 270° signals to the antenna radiators. The feed network utilizes a combination of one or more branch line couplers and one or more power dividers to accept an input signal from a transmitter and to provide therefrom the 0°, 90°, 180° and 270° signals needed to drive the antenna. For receive operations, the feed network utilizes these same components to receive the 0°, 90°, 180° and 270° signals from the antenna radiators and to provide a single output signal to a communications receiver. The power divider accepts an input signal and provides therefrom two output signals differing from each other in phase by 180°. The branch line coupler accepts an input signal and provides therefrom two output signals differing from one another in phase by 90°.

Claims

1. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a branch line coupler having an input arm for accepting an input signal and a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

;

a first power divider connected to said first output of said branch line coupler for accepting said first output signal and for providing therefrom third and fourth output signals, wherein said third and fourth output signals differ from one another by 180°

; and

a second power divider connected to said second output of said branch line coupler for accepting said second output signal and for providing therefrom fifth and sixth output signals, wherein said fifth and sixth output signals differ from one another by 180°

;

wherein said first and second power dividers each comprise;

a substrate,

a first conductive path disposed on a first surface of said substrate,

a ground portion disposed on a second surface of said substrate forming a ground plane and tapering from said ground plane to form a second conductive path having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate,

a tab disposed on said second surface and extending from said second conductive path, and

an electrical connection between said tab on said second surface and said third conductive path on said first surface.

2. The antenna of claim 1 wherein said branch line coupler is a single section branch line coupler.

3. The antenna of claim 1 wherein said branch line coupler is a double section branch line coupler.

4. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a branch line coupler having an input arm for accepting an input signal and a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

;

a first power divider connected to said first output of said branch line coupler for accepting said first output signal and for providing therefrom third and fourth output signals, wherein said third and fourth output signals differ from one another by 180°

; and

a second power divider connected to said second output of said branch line coupler for accepting said second output signal and for providing therefrom fifth and sixth output signals, wherein said fifth and sixth output signals differ from one another by 180°

;

wherein said first and second power dividers each comprise;

a substrate,

a first conductive path disposed on a first surface of said substrate,

a ground portion disposed on a second surface of said substrate forming a ground plane and tapering from said ground plane to form a second conductive path having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate, and

an electrical connection between said second conductive path and said third conductive path.

5. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a branch line coupler having an input arm for accepting an input signal and a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

;

a first power divider connected to said first output of said branch line coupler for accepting said first output signal and for providing therefrom third and fourth output signals, wherein said third and fourth output signals differ from one another by 180°

; and

a second power divider connected to said second output of said branch line coupler for accepting said second output signal and for providing therefrom fifth and sixth output signals, wherein said fifth and sixth output signals differ from one another by 180°

;

wherein said first and second power dividers each comprise;

a substrate having an input area, a transition area, and an output area,

a first conductive path disposed on a first surface of said substrate and spanning said input area, said transition area and said output area,

a ground portion disposed on a second surface of said substrate forming a ground plane in said input area of said substrate, and tapering from the ground plane to form a tapered portion in said transition area of said substrate,

a second conductive path extending from said tapered portion on said second surface of said substrate and having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate in said output area of said substrate,

a tab disposed on said second surface and extending from said second conductive path, and

an electrical connection between said tab on said second surface and said third conductive path on said first surface.

6. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a branch line coupler having an input arm for accepting an input signal and a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

;

a first power divider connected to said first output of said branch line coupler for accepting said first output signal and for providing therefrom third and fourth output signals, wherein said third and fourth output signals differ from one another by 180°

; and

a second power divider connected to said second output of said branch line coupler for accepting said second output signal and for providing therefrom fifth and sixth output signals, wherein said fifth and sixth output signals differ from one another by 180°

;

wherein said first and second power dividers each comprise;

a substrate having an input area a transition area and an output area,

a first conductive path disposed on a first surface of said substrate and spanning said input area, said transition area and said output area,

a ground portion disposed on a second surface of said substrate forming a ground plane in said input area of said substrate, and tapering from the ground plane to form a tapered portion in said transition area of said substrate,

a second conductive path extending from said tapered portion on said second surface of said substrate and having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate in said output area of said substrate, and

an electrical connection between said second conductive path on said second surface and said third conductive path on said first surface.

7. The antenna of claim 6, wherein at least one of said first, second and third conductive paths are wider in said output area of said substrate to reduce the characteristic impedance of the device.

8. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a power divider for providing from an input signal first and second output signals that differ from each other by 180°

, wherein said power divider comprises;

a substrate,

a first conductive path disposed on a first surface of said substrate,

a ground portion disposed on a second surface of said substrate forming a ground plane and tapering from said ground plane to form a second conductive path having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate,

a tab disposed on said second surface and extending from said second conductive path, and

an electrical connection between said tab on said second surface and said third conductive path on said first surface;

a first branch line coupler having an input arm for accepting said first signal from said power divider and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

; and

a second branch line coupler having an input arm for accepting said second output signal from said power divider and further having a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

.

9. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a power divider for providing from an input signal first and second output signals that differ from each other by 180°

, wherein said power divider comprises;

a substrate,

a first conductive path disposed on a first surface of said substrate,

a ground portion disposed on a second surface of said substrate forming a ground plane and tapering from said ground plane to form a second conductive path having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate, and

an electrical connection between said second conductive path and said third conductive path;

a first branch line coupler having an input arm for accepting said first signal from said power divider and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

; and

a second branch line coupler having an input arm for accepting said second output signal from said power divider and further having a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

.

10. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate; and

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a power divider for providing from an input signal first and second output signals that differ from each other by 180°

, wherein said power divider comprises;

a substrate having an input area a transition area and an output area,

a first conductive path disposed on a first surface of said substrate and spanning said input area, said transition area and said output area,

a ground portion disposed on a second surface of said substrate forming a ground plane in said input area of said substrate, and tapering from the ground plane to form a tapered portion in said transition area of said substrate,

a second conductive path extending from said tapered portion on said second surface of said substrate and having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path,

a third conductive path disposed on said first surface of said substrate in said output area of said substrate,

a tab disposed on said second surface and extending from said second conductive path, and

an electrical connection between said tab on said second surface and said third conductive path on said first surface;

a first branch line coupler having an input arm for accepting said first signal from said power divider and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

; and

a second branch line coupler having an input arm for accepting said second output signal from said power divider and further having a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

.

11. A quadrifilar helix antenna, comprising:

four radiators etched onto a radiator portion of a microstrip substrate;

a feed network etched onto a feed portion of said microstrip substrate and providing 0°

, 90°

, 180° and

270°

signals to said radiators, said feed network comprising;

a power divider for providing from an input signal first and second output signals that differ from each other by 180°

, wherein said power divider comprises;

a substrate having an input area a transition area and an output area,

a first conductive path disposed on a first surface of said substrate and spanning said input area, said transition area and said output area,

a ground portion disposed on a second surface of said substrate forming a ground plane in said input area of said substrate, and tapering from the ground plane to form a tapered portion in said transition area of said substrate,

a second conductive path extending from said tapered portion on said second surface of said substrate and having a width that is substantially equal to the width of said first conductive path and being positioned on said second surface substantially in alignment with said first conductive path.

a third conductive path disposed on said first surface of said substrate in said output area of said substrate, and

an electrical connection between said second conductive path on said second surface and said third conductive path on said first surface;

a first branch line coupler having an input arm for accepting said first signal from said power divider and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

; and

a second branch line coupler having an input arm for accepting said second output signal from said power divider and further having a first output arm for providing a first output signal and a second output arm for providing a second output signal, wherein said first and second output signals differ from one another by 90°

.

12. The antenna of claim 11, wherein at least one of said first, second and third conductive paths are wider in said output area of said substrate to reduce the characteristic impedance of the device.