Compact, ultra-broadband antenna with doughnut-like radiation pattern

1. An antenna comprising:

a first assembly having first and second ends;

a second assembly having first and second ends, the first and second ends of both of the first and second assemblies having a substantially hemispherical shape; and

a cable configured to extend through the first and second assemblies.

2. The antenna of claim 1 , wherein the cable is comprised of inner and outer conductors.

3. The antenna of claim 2 , wherein only the outer conductor is electrically connected to the first assembly.

4. The antenna of claim 3 , wherein both the inner and outer conductors are electrically connected to the second assembly.

5. The antenna of claim 3 , wherein only the inner conductor is electrically connected to the second assembly.

6. The antenna of claim 2 , wherein the first and second assemblies are disposed separate from each other, the cable extends in a gap between the first and second assemblies, and the outer conductor is removed from a portion of the cable in the gap.

7. The antenna of claim 6 , wherein the inner conductor is exposed at the portion of the cable where the outer conductor is removed.

8. The antenna of claim 2 , wherein the first and second assemblies are disposed separate from each other with a gap in between, and the outer conductor is removed from the cable in the gap and from the cable extending through and out of the second assembly.

9. The antenna of claim 2 , wherein the inner and outer conductors are shorted together at a terminal end outside the second assembly.

10. The antenna of claim 1 , wherein the cable extends out each of the first and second ends.

11. The antenna of claim 1 , wherein exterior surfaces of the first and second assemblies are conductive.

12. The antenna of claim 1 , wherein the first and second assemblies of both of the first and second assemblies each comprise a mid-section between the respective first and second ends of the first and second assemblies, wherein a diameter of each of the mid-sections is greater than a diameter at the respective first and second ends of the first and second assemblies.

13. The antenna of claim 1 , wherein the first and second assemblies of both of the first and second assemblies each comprise a mid-section between the respective first and second ends of the first and second assemblies, wherein each of the mid-sections have a substantially uniform diameter between the first and second ends.

14. The antenna of claim 1 , having an impedance and an azimuthally omni-directional far field pattern that are ultra-broadband.

15. The antenna of claim 14 , wherein an elevation plane of the far field pattern is substantially free of nulls that are less than −10 dB in zenith and anti-zenith directions.

16. The antenna of claim 1 , wherein the first assembly comprises a first assembly section and a second assembly section, the first assembly section of the first assembly being electrically connected to the second assembly section of the first assembly at a seam, the antenna comprising a conical bulge in the first assembly section of the first assembly at the seam.

17. The antenna of claim 16 , wherein the conical bulge is a first conical bulge, and the second assembly section of the first assembly comprises a second conical bulge at the seam.

18. The antenna of claim 1 , wherein the second assembly comprises a first assembly section and a second assembly section, the first assembly section of the second assembly being electrically connected to the second assembly section of the second assembly at a seam, the antenna comprising a conical bulge in the first assembly section of the second assembly at the seam.

19. The antenna of claim 18 , wherein the conical bulge is a first conical bulge, and the second assembly section of the second assembly comprises a second conical bulge at the seam.