Nested wire monopole HF antenna
Methods and apparatus for an antenna having first and second nested monopoles each having arms with bends. In some embodiments, the monopoles are offset in clocking angle. In some embodiments, the monopoles are aligned in clocking angle. In embodiments, the bends in the arms may be located at half a total height of the antenna.
1. An antenna, comprising:
a first monopole having a first number of arms and a top and a bottom, wherein the arms of the first monopole have bends; and
a second monopole having a second number of arms, wherein the second monopole has a height less than a height of the first monopole, and wherein the second monopole is at least partially nested within the first monopole.
2. The antenna according to claim 1 , wherein the first monopole is offset in clocking angle from the second monopole.
3. The antenna according to claim 1 , wherein the first and second monopoles are aligned in clocking angle.
4. The antenna according to claim 1 , wherein the first and second numbers of arms are equal.
5. The antenna according to claim 1 , wherein the first number of arms is three.
6. The antenna according to claim 1 , wherein the first number of arms is between two and seven.
7. The antenna according to claim 1 , wherein the arms of the second monopole each have a bend.
8. The antenna according to claim 7 , wherein the bends in the arms of the first monopole form the first monopole into a diamond shape.
9. The antenna according to claim 8 , wherein the bends in the arms of the first monopole are located at one half a height of the antenna formed by the first and second monopoles.
10. The antenna according to claim 9 , wherein the bends in the arms of the first monopole define a width of the antenna.
11. The antenna according to claim 1 , wherein the antenna has a single feed for the first and second monopoles.
12. The antenna according to claim 1 , wherein portions of the arms of the first monopole are shared by portions of the arms of the second monopole.
13. The antenna according to claim 1 , wherein the arms of the first monopole have a diameter ranging from about 0.09 to 0.1λ, where λ is a wavelength of a mid-frequency of an operating band of the antenna.
14. The antenna according to claim 1 , wherein the antenna formed by the first and second monopoles does not include lumped elements.
15. The antenna according to claim 1 , wherein the antenna provides ultra-wideband performance covering over 9:1 bandwidth.
16. The antenna according to claim 1 , wherein the antenna forms part of an over-the-horizon radar.
17. The antenna according to claim 16 , further including low-band and high-band arrays formed from elements comprising the first and second monopoles.
18. The antenna according to claim 1 , further comprising:
a third monopole having a third number of arms, wherein the third monopole has a height less than the height of the second monopole, and wherein the third monopole is at least partially nested within the second monopole.
19. A system, comprising:
a feedline;
a ground plane attached to one side of the feedline; and
first and second monopoles coupled to another side of the feedline, the second monopole at least partially nested within the first monopole;
wherein the first monopole has a first number of arms and a top and a bottom, wherein the arms of the first monopole have bends; and
wherein the second monopole has a second number of arms, wherein the second monopole has a height less than a height of the first monopole.
20. A method, comprising:
radiating a signal with an antenna comprising first and second monopoles;
wherein:
the first monopole has a first number of arms and a top and a bottom, wherein the arms of the first monopole have bends; and
the second monopole has a second number of arms, wherein the second monopole has a height less than a height of the first monopole, and wherein the second monopole is at least partially nested within the first monopole.