A loop antenna array, comprising: a plurality of magnetic quadrupoles each comprising: two loop antennas (1,2) through which currents flow in opposite directions such that the magnetic dipole moments of the two loop antennas point in opposite directions, wherein: the two loop antennas have the same shape, the two loop antennas (1,2) are arranged on the same plane, and the centers of the loop antennas are arranged along a straight-line segment on said plane, and a distance (d) between centers of the two loop antennas (1c,2c) is shorter than twice a distance to a communication area boundary, which is a magnetic field strength contour in a plane perpendicular to the plane of the two loop antennas and not intersecting the plane of the two loop antennas, the loop antenna array being further characterized in that: the total number of magnetic quadrupoles included in the loop antenna array is 2 to the n-1 power, wherein n is an integer of more than 2, wherein the loop antenna array is formed in iterative groups from 1 to n, such that in the first group the loop antenna array includes a single quadrupole arranged along the straight-line segment, and in each of the following groups the loop antenna array includes first and second unit arrays arranged along the straight-line segment, wherein the first unit array includes the loop antenna array of the previous group, and the second unit array includes the loop antenna array of the previous group with the current directions of the loop antennas reversed. two loop antennas (1,2) through which currents flow in opposite directions such that the magnetic dipole moments of the two loop antennas point in opposite directions, wherein: the two loop antennas have the same shape, the two loop antennas (1,2) are arranged on the same plane, and the centers of the loop antennas are arranged along a straight-line segment on said plane, and a distance (d) between centers of the two loop antennas (1c,2c) is shorter than twice a distance to a communication area boundary, which is a magnetic field strength contour in a plane perpendicular to the plane of the two loop antennas and not intersecting the plane of the two loop antennas, the loop antenna array being further characterized in that: the total number of magnetic quadrupoles included in the loop antenna array is 2 to the n-1 power, wherein n is an integer of more than 2, wherein the loop antenna array is formed in iterative groups from 1 to n, such that in the first group the loop antenna array includes a single quadrupole arranged along the straight-line segment, and in each of the following groups the loop antenna array includes first and second unit arrays arranged along the straight-line segment, wherein the first unit array includes the loop antenna array of the previous group, and the second unit array includes the loop antenna array of the previous group with the current directions of the loop antennas reversed. the two loop antennas have the same shape, the two loop antennas (1,2) are arranged on the same plane, and the centers of the loop antennas are arranged along a straight-line segment on said plane, and a distance (d) between centers of the two loop antennas (1c,2c) is shorter than twice a distance to a communication area boundary, which is a magnetic field strength contour in a plane perpendicular to the plane of the two loop antennas and not intersecting the plane of the two loop antennas, the loop antenna array being further characterized in that: the total number of magnetic quadrupoles included in the loop antenna array is 2 to the n-1 power, wherein n is an integer of more than 2, wherein the loop antenna array is formed in iterative groups from 1 to n, such that in the first group the loop antenna array includes a single quadrupole arranged along the straight-line segment, and in each of the following groups the loop antenna array includes first and second unit arrays arranged along the straight-line segment, wherein the first unit array includes the loop antenna array of the previous group, and the second unit array includes the loop antenna array of the previous group with the current directions of the loop antennas reversed. the total number of magnetic quadrupoles included in the loop antenna array is 2 to the n-1 power, wherein n is an integer of more than 2, wherein the loop antenna array is formed in iterative groups from 1 to n, such that in the first group the loop antenna array includes a single quadrupole arranged along the straight-line segment, and in each of the following groups the loop antenna array includes first and second unit arrays arranged along the straight-line segment, wherein the first unit array includes the loop antenna array of the previous group, and the second unit array includes the loop antenna array of the previous group with the current directions of the loop antennas reversed.