Coaxial helix antennas
Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.
1. A coaxial helix antenna, comprising:
an inner element having an inner element radius and an inner element length; and
an outer element having an outer element radius and an outer element length;
wherein the outer element radius is greater than the inner element radius;
wherein the inner element is driven by a first conductor;
wherein the outer element is driven by a second conductor;
wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and comprises an inner radiating element;
wherein the coaxial helix antenna is connected to a coaxial cable;
wherein the coaxial cable comprises a conductor and an outer shield
wherein the outer element is coupled to the conductor such that the second conductor comprises the conductor of the coaxial cable; and
wherein the inner element is coupled to the outer shield such that the first conductor comprises the outer shield of the coaxial cable.
2. The coaxial helix antenna of claim 1 , wherein:
the coaxial helix antenna further comprises a BNC connector;
the inner element and the outer element are connected to the BNC connector;
the coaxial cable is connected to a mating BNC connector capable of engaging with the BNC connector;
the inner element is electrically coupled to the outer shield via the BNC connector when engaged with the mating BNC connector; and
the outer element is electrically coupled to the conductor via the BNC connector when engaged with the mating BNC connector.
3. The coaxial helix antenna of claim 1 , wherein the outer element and the inner element are wound in an opposite manner.
4. The coaxial helix antenna of claim 3 , wherein:
the outer element is wound in a clockwise manner; and
the inner element is wound in a counter-clockwise manner.
5. The coaxial helix antenna of claim 3 , wherein:
the inner element is wound in a clockwise manner; and
the outer element is wound in a counter-clockwise manner.
6. The coaxial helix antenna of claim 1 , wherein the coaxial helix antenna is installed within the frame of a vehicle, where the frame of the vehicle is constructed using a conductive material.
7. A coaxial helix antenna system, comprising:
a feedline comprising a first side and a second side;
an inner radiative element having an inner radiative element radius and an inner radiative element length; and
an outer radiative element having an outer radiative element radius and an outer radiative element length;
wherein the outer radiative element radius is greater than the inner radiative element radius;
wherein the inner radiative element is driven by a first conductor;
wherein the outer radiative element is driven by a second conductor;
wherein the outer radiative element is disposed outside of the inner radiative element such that a portion of the inner radiative element extends beyond the outer radiative element;
wherein the inner radiative element is connected to the first side of the feedline; and
wherein the outer radiative element is connected to the second side of the feedline.
8. The coaxial helix antenna system of claim 7 , wherein:
the feedline is a coaxial cable;
the coaxial helix antenna is connected to a coaxial cable; and
the coaxial cable comprises a conductor and an outer shield.
9. The coaxial helix antenna system of claim 8 , wherein:
the outer radiative element is coupled to the conductor such that the second conductor comprises the conductor of the coaxial cable; and
the inner radiative element is coupled to the outer shield such that the first conductor comprises the outer shield of the coaxial cable.
10. The coaxial helix antenna system of claim 8 , wherein:
the coaxial helix antenna further comprises a BNC connector;
the inner radiative element and the outer radiative element are connected to the BNC connector;
the coaxial cable is connected to a mating BNC connector capable of engaging with the BNC connector;
the inner radiative element is electrically coupled to the outer shield via the BNC connector when engaged with the mating BNC connector; and
the outer radiative element is electrically coupled to the conductor via the BNC connector when engaged with the mating BNC connector.
11. The coaxial helix antenna system of claim 7 , wherein the outer radiative element and the inner radiative element are wound in an opposite manner.
12. The coaxial helix antenna system of claim 11 , wherein:
the outer radiative element is wound in a clockwise manner; and
the inner radiative element is wound in a counter-clockwise manner.
13. The coaxial helix antenna system of claim 11 , wherein:
the inner radiative element is wound in a clockwise manner; and
the outer radiative element is wound in a counter-clockwise manner.
14. The coaxial helix antenna system of claim 7 , wherein the coaxial helix antenna is installed within the frame of a vehicle, where the frame of the vehicle is constructed using a conductive material.
15. The coaxial helix antenna system of claim 7 , further comprising an insulator located between the inner radiative element and the outer radiative element.
16. The coaxial helix antenna system of claim 15 , wherein the insulator does not extend beyond the outer radiative element.