UNDERGROUND ANTENNA

• US 3,594,798 A
• Filed: 03/09/1966
• Issued: 07/20/1971
• Est. Priority Date: 03/09/1966
• Status: Expired due to Term

• Current Assignee: George F. Leydorf, Lucien W. Rawls
• Original Assignee: George F. Leydorf, Lucien W. Rawls
• Inventors: Leydorf, George F., Rawls, Lucien W.
• Application Number:
  US04/556,248
• Time in Patent Office: 1,959 Days
• US Class Current: 343/719
• CPC Class Codes: H01Q 1/04 Adaptation for subterranean or subaqueous use

Abstract

The present invention relates in general to a hardened antenna, and in particular to a broadside array antenna which is placed at or below the surface of the ground, which is capable of withstanding the shock of explosions such as nuclear blasts.

Claims

1. An underground high redundancy antenna system comprising a plurality of dipole antennas, each dipole antenna comprising feed line means and a plurality of parallel wires forming each side of each dipole antenna, said wires extending in opposite direction from said feed line means and connected to said feed line means in parallel, the wires of each of said sides being spaced apart a sufficient distance at a sufficient depth to enable the earth to substantially reduce the mutual coupling between the wires, each of said antennas being insulated over a major portion thereof, and conductive means in contact with the earth connected to the ends of said wires to reduce the power loss, said dipole antennas being spaced from each other in the direction in which said wires extend.

2. An antenna system according to claim 1 including a second plurality of dipole antennas constructed similarly to said first plurality of dipole antennas, said second dipole antennas having their wires extending substantially at right angles to the wires of the first plurality of dipole antennas and feed line means connected to said second dipole antennas.

3. For use in the transmission of radio frequencies, an underground antenna comprising at least one dipole antenna, each side of said dipole antenna including a plurality of substantially parallel wires to thereby increase the launching efficiency of said antenna, said parallel wires being spaced apart a sufficient distance at a specified depth within the earth to enable the earth to substantially reduce the mutual coupling between the wires, said wires being insulated over at least a portion of their length, the thickness of said insulation being related to the loss characteristics of the adjacent earth.

4. An underground antenna according to claim 3, wherein a sufficient length of the end of each of said wires is in a conductive relationship with the earth to reduce the power loss in the antenna.

5. An underground array antenna comprising a plurality of spaced pairs of colinear conductors lying beneath and in close proximity to the surface of the earth, each of said conductors having a coating of insulation over a portion thereof, the other portion of each of said conductors being in direct contact with the earth, each of said pair of conductors being of a length not greater that one-third of a wavelength in free space of the energy radiated thereby, the spacing between each of said pairs of conductors being substantially equal to 2 delta , delta being the skin depth of the earth, for substantially reducing the mutual coupling between adjacent pairs of conductors.

6. The antenna of claim 5 wherein said plurality is chosen to be of such a number that the overall distance between the outermost conductors is substantially equal to one-Third of the wavelength in free space of the energy radiated thereby.