METHOD OF DETECTING SUBSURFACE OBJECTS

• US 3,745,575 A
• Filed: 02/01/1972
• Issued: 07/10/1973
• Est. Priority Date: 02/09/1971
• Status: Expired due to Term

• Current Assignee: Hideyuki Kikuchi
• Original Assignee: Hideyuki Kikuchi
• Inventors: Kikuchi, Hideyuki
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US05/222,631
• Time in Patent Office: 525 Days
• Field of Search: 343/5R,17R 324/6
• US Class Current: 342/22
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

A method of detecting subsurface objects such as ore deposits by producing a graded transition layer for the propagation of electromagnetic waves having, for example, an exponential or square law characteristic at the air-water or air-earth interface by directing an electromagnetic wave from a stereo antenna through a non-linear element having, for example, an exponential or square law characteristic and a half-wavelength space transformer and, when desired, by simultaneously directing another electromagnetic wave from a linear antenna to the interface to enable the electromagnetic waves to pass through the interface to penetrate into the water or earth and to be reflected by the subsurface objects into the air.

Claims

1. A method of detecting subsurface objects in which a first electromagnetic wave having a first angular frequency is directed through a non-linear element and a half-wavelength space transformer to the air-water or air-earth interface, whereby a graded transition layer for the propagation of said electromagnetic wave is produced at said interface to enable said electromagnetic wave to pass through said interface to penetrate into the water or earth to be reflected or backscattered or forwardscattered by subsurface objects into the air.

2. A method of detecting subsurface objects according to claim 1, in which said non-linear element and said transition layer have exponential or square law characteristics.

3. A method of detecting subsurface objects according to claim 1, in which a second electromagnetic wave having a second angular frequency which is different from said first frequency is directed to said interface simultaneously with said first electromagnetic wave.

4. A method of detecting subsurface objects according to claim 3, in which said first electromagnetic wave is emitted from a stereo antenna and said second electromagnetic wave is emitted from a linear antenna, whereby the coherent component of said second electromagnetic wave interferes with said first electromagnetic wave and the incoherent component of said second electromagnetic wave effects parametric jumping of said first electromagnetic wave.

5. A method of detecting subsurface objects according to claim 3, in which both of said first and second electromagnetic waves are emitted from respective stereo antennas, and said first and second electromagnetic waves form a beat wave which is detected in said transition layer and reflection modulated when it is reflected by said subsurface objects.

6. A method of detecting subsurface objects according to claim 3, in which said electromagnetic waves are in the intermittent or pulse form so that the reflected waves can be separated, and said reflected two waves are subjected to phase comparison to effect range determination.

7. A method of detecting subsurface objects according to claim 6, in which said reflected waves are separately received by separate receivers to monitor the generation of said transition layer.