Multiband jamming antenna
Disclosed is a multiband jamming antenna for use with RF jamming systems. An exemplary embodiment of the antenna comprises high-band, medium-band and low-band radiating structures arranged in a collinear manner. The three radiating structures are operable in three respective overlapping frequency bands. In the exemplary embodiment, the high-band radiating structure comprises a hybrid biconical/dipole antenna disposed at an upper end of the antenna. The medium-band radiating structure is collinearly coupled to the high-band radiating structure and comprises upper and lower dipole elements that are tuned using a dual section coaxial transformer. The low-band radiating structure is collinearly coupled to the medium-band radiating structure. The low-band radiating structure comprises a coaxial Ruthroff UNUN transformer that is coupled to the low-band radiating structure, and a feeder cable that connected to the coaxial Ruthroff UNUN transformer, and the high-band, medium-band, and low-band radiating structures.
1. Antenna apparatus, comprising:
a high-band radiating structure that comprises a hybrid biconical/dipole antenna disposed at an upper end of the apparatus;
a medium-band radiating structure collinearly coupled to the high-band radiating structure that comprises upper and lower dipole elements and that is tuned with a dual section coaxial transformer; and
a low-band radiating structure collinearly coupled to the medium-band radiating structure that comprises:
a coaxial Ruthroff UNUN transformer coupled to the low-band radiating structure; and
a feeder cable connected to the coaxial Ruthroff UNUN transformer, and the high-band, the medium-band, and the low-band radiating structures.
2. The apparatus recited in claim 1 further comprising:
a spring-loaded mounting structure coupled to the low-band radiating structure.
3. The apparatus recited in claim 1 wherein the low-band radiating structure operates between about 20 MHz and about 500 MHz, the medium-band radiating structure operates between about 120 MHz and about 1 GHz and the high-band radiating structure operates between about 500 MHz and about 6 GHz.
4. The apparatus recited in claim 1 wherein the hybrid biconical dipole radiating structure comprises an upper tapered conical dipole radiating element coupled to a lower tapered conical dipole radiating element by way of a balun.
5. The apparatus recited in claim 1 wherein the medium-band radiating structure comprises upper and lower dipole elements coupled to a dual section coaxial transformer.
6. The apparatus recited in claim 1 wherein the high-band feeder line cable makes a 540 degree arc around the mid-band feed point while providing a 180 degree phase imbalance necessary for proper mid-band operation.
7. The apparatus recited in claim 1 wherein the spring-loaded mounting structure comprises:
top and bottom plates;
a plurality of laterally-offset springs coupled between the top and bottom plates.
8. The apparatus recited in claim 1 wherein the spring-loaded mounting structure comprises:
a top plate for connecting to the antenna structure;
a bottom plate for connecting to a vehicle; and
a plurality of laterally-offset springs coupled between the top and bottom plates.
9. The apparatus recited in claim 1 wherein the is enclosed by flexible bellow that is secured to the top and bottom plates.
10. The apparatus recited in claim 1 wherein the spring-loaded mounting structure comprises molded rubber elements disposed within each of the springs.