Steerable three-dimensional magnetic field sensor system for detection and classification of metal targets

A sensor system for inducing eddy currents in objects comprising:

• 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.

A sensor system comprising:

• 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.

An antenna system for introducing eddy currents in objects comprising:

• 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.

A sensor system comprising:

• 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.