Steerable three-dimensional magnetic field sensor system for detection and classification of metal targets
First Claim
1. A sensor system for inducing eddy currents in objects comprising:
- an antenna configured for generating a magnetic field in a direction perpendicular to current flow in a plurality of wires along a plane of the antenna;
at least two receiver units in proximity to the plane of the antenna, each of said two receiver units configured for converting the eddy currents into a first signal and a second signal; and
an amplifier for receiving the first and second signals.
1 Assignment
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Accused Products
Abstract
A steerable electromagnetic induction (EMI) sensor system for measuring the magnetic polarizability tensor of a metal target. Instead of creating a vertical magnetic field from a horizontal loop transmitter configuration used by most prior art EMI metal detectors, the transmitter geometry of the sensor system'"'"'s antenna is designed especially for creating multiple horizontal and vertical magnetic fields and for steering the same in all directions. The horizontal magnetic field (HMF) antenna has the potential advantage of a relatively uniform magnetic field over a large volume. A second potential advantage of the HMF antenna is that compared to a conventional loop antenna, the magnetic field intensity falls off slowly with distance from the plane of the antenna. Combining two HMF sensor systems creates a steerable two-dimensional magnetic field sensor. Combining the steerable HMF sensor with a vertical magnetic field antenna forms a three-dimensional steerable magnetic field sensor system.
20 Citations
30 Claims
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1. A sensor system for inducing eddy currents in objects comprising:
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an antenna configured for generating a magnetic field in a direction perpendicular to current flow in a plurality of wires along a plane of the antenna; at least two receiver units in proximity to the plane of the antenna, each of said two receiver units configured for converting the eddy currents into a first signal and a second signal; and an amplifier for receiving the first and second signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A sensor system for inducing eddy currents in objects comprising:
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an antenna configured for generating a pulsed magnetic field in a direction perpendicular to current flow in a plurality of wires along a plane of the antenna; at least two receiver units in proximity to the plane of the antenna , each of said two receiver units configured for converting the eddy currents into a first signal and a second signal; and an amplifier for receiving the first and second signals; wherein the antenna includes a first bank and a second bank of switches, the first bank of switches is at one end of the antenna and the second bank of is at an opposite end of the antenna, and the first bank of switches and the second bank of switches are connected by a plurality of return wire loops and the plurality of wires along the plane of the antenna. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A sensor system comprising:
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first, second and third antennas configured for generating respective magnetic fields in three directions perpendicular to each other; wherein the first antenna has a plurality of wires along a plane thereof for generating a magnetic field in a first direction perpendicular to the current flow in the plurality of wires; and control circuitry configured to control the generation of a pulsed magnetic field to produce a magnetic field in selected ones of said three directions, including to selectively produce a magnetic field in the direction perpendicular to the current flow in the plurality of wires; wherein the first antenna includes a first bank and a second bank of switches, the first bank of switches is at one end of the first antenna and the second bank of switches is at an opposite end of the first antenna, and the first bank of switches and the second bank of switches are connected by a plurality of return wire loops and the plurality of wires. - View Dependent Claims (22)
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23. An antenna system for introducing eddy currents in objects comprising:
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a first antenna configured for generating a pulsed magnetic field in the x-axis direction; a second antenna configured for generating a pulsed magnetic field in the y-axis direction and oriented at a 90-degree angle with respect to the first antenna; and a third antenna configured for generating a pulsed magnetic field in the z-axis direction and encircling the first and second antennas. - View Dependent Claims (24, 25)
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26. A sensor system comprising:
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first, second and third antennas configured for generating respective pulsed magnetic fields in three directions perpendicular to each other; wherein the first antenna has a plurality of wires along a plane thereof for generating a pulsed magnetic field in a first direction perpendicular to the current flow in the plurality of wires; and control circuitry configured to control the generation of a pulsed magnetic field to produce a pulsed magnetic field in selected ones of said three directions, including to selectively produce a pulsed magnetic field in the direction perpendicular to the current flow in the plurality of wires. - View Dependent Claims (27, 28, 29, 30)
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Specification