Patent ID: 8324894
Filing Date: 2012-12-04
Classification: G01N

Abstract:
1. An eddy current sensor comprising: a source antenna comprising two sub-loops substantially symmetrical with respect to an imaginary line between the two sub-loops; and a first transmission line for communicating with an external circuit, wherein the source antenna is adapted to generate a magnetic quadrupole when electric currents circulate on the two sub-loops in opposing directions, wherein the source antenna is adapted to induce a substantially linearly polarized electric field in a region between the two sub-loops, wherein the source antenna further comprises a first loop conductor, bisected by a first imaginary line crossing the first loop conductor at a first point and a second point, such that a first part and a second part of the loop conductor on a first side and a second side of the first imaginary line comprise at least part of a first sub-loop and a second sub-loop, respectively, among the two sub-loops, wherein the first transmission line comprises a first conductor and a second conductor, and wherein the first transmission line crosses the first point such that the first conductor is electrically coupled with the first loop conductor at about the first point; and wherein the first conductor extends toward an inside of the first loop conductor along the first imaginary line and ends at a third point, on the first imaginary line, and the second conductor extends along the first imaginary line beyond the third point, to be electrically coupled with the first loop conductor at the second point.