JP5987022B2 - 3-axis loop antenna - Google Patents

Description

  The present invention relates to a triaxial loop antenna.

を行うことで、磁界の絶対値を検出できる。このような検出は、例えば図８の回路構成によって実現可能である。 A wireless communication system using a magnetic field has been proposed (Patent Document 1). In such a system, a terminal having isotropic detection sensitivity to a magnetic field is required. One means for achieving isotropic magnetic field detection sensitivity is to detect the absolute value of the magnetic field vector. For this purpose, first, three spatial components (Bx, By, Bz) of the magnetic field vector B are detected using a three-axis loop antenna composed of three orthogonal loop antennas (conductor loops). In addition, absolute value calculation for three spatial components

By performing the above, the absolute value of the magnetic field can be detected. Such detection can be realized by the circuit configuration of FIG. 8, for example.

JP2013-125991A

  As a means for realizing a three-axis loop antenna, a structure in which loop antennas (conductor loops) are arranged on three orthogonal surfaces among the six surfaces of a cube has been proposed (FIG. 9).

  The problem with this structure is that the mutual inductance between the loop antennas is not zero, so that an error occurs in the spatial component of the detected magnetic field vector. As a specific example, consider the case of B = (0,0, Bz). In this case, the reception current Iz flows through the z loop when Bz penetrates the z loop. However, since the magnetic flux generated by Iz passes through the y loop and the x loop and the reception currents Iy and Ix are generated, By and Bx that should not exist originally are erroneously detected. As a result, the accuracy of the absolute value (| B |) of the detected magnetic field decreases.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a three-axis loop antenna having a small mutual inductance and capable of detecting a magnetic field with high accuracy.

In order to solve the above-described problem, a triaxial loop antenna according to a first aspect of the present invention is a triaxial loop antenna including conductor loops arranged along three surfaces having a perpendicular relationship with each other in space. The first conductor loop is disposed along the first surface including a line symmetry axis that divides the inner region of the second conductor loop in a line-symmetric manner, and the second conductor loop includes the third conductor loop. A square or rectangular first substrate disposed along the second plane including a line symmetry axis that divides the inner region of the conductor loop in a line-symmetric manner , and having the first conductor loop as a substrate pattern; A square or rectangular second substrate having a conductor loop as a substrate pattern; and a third square or rectangular third substrate having a third conductor loop as a substrate pattern. An end surface of the first substrate is opposed to one surface of the second substrate, a second end surface of the first substrate perpendicular to the first end surface of the first substrate is opposed to one surface of the third substrate, and 3 a first end surface of the substrate and wherein the opposed to Rukoto on the one surface of the second substrate.
A triaxial loop antenna according to a second aspect of the present invention is a triaxial loop antenna including conductor loops arranged along each of three surfaces that are perpendicular to each other in space, wherein the first conductor loop includes: The second conductor loop is arranged along the first plane including a line symmetry axis that divides the inner region of the two conductor loops in line symmetry, and the second conductor loop is arranged in line symmetry with the inner region of the third conductor loop. The substrate is a square or rectangular substrate disposed along the second surface including the line symmetry axis to be divided, and a slit toward the second end surface parallel to the end surface is formed on the first end surface of the substrate. A first substrate having the first conductor loop as a substrate pattern, a square or rectangular second substrate having the second conductor loop as a substrate pattern, and a third conductor loop as a substrate pattern. A square or rectangular third substrate, a first end surface of the first substrate is opposed to one surface of the second substrate, and a peripheral portion of a slit of the first substrate is the third substrate. The first end surface of the third substrate is opposed to the one surface of the second substrate.

  The triaxial loop antenna of the present invention has a small mutual inductance and can detect a magnetic field with high accuracy.

The triaxial loop antenna which concerns on 1st Embodiment is shown. The triaxial loop antenna which concerns on 2nd Embodiment is shown. The top view of the 1st substrate 2x, the 2nd substrate 2y, and the 3rd substrate 2z is shown. The triaxial loop antenna which concerns on 3rd Embodiment is shown. The triaxial loop antenna which concerns on 4th Embodiment is shown. 10 shows a triaxial loop antenna according to a fifth embodiment. 9 shows a triaxial loop antenna according to a sixth embodiment. The example of the circuit structure of the conventional magnetic field detection is shown. An example of a conventional triaxial loop antenna is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
A triaxial loop antenna according to the first embodiment is shown in FIG.
The triaxial loop antenna includes conductor loops 1x, 1y, and 1z arranged along each of three surfaces that are perpendicular to each other in space. The surface here is a geometric surface. That is, it means a two-dimensional spread and does not need to be accompanied by an entity.

  The conductor loops 1x, 1y, and 1z are arranged along a plane perpendicular to the x-axis, a plane perpendicular to the y-axis, and a plane perpendicular to the z-axis, respectively.

The first conductor loop 1x is disposed along a first surface including a line symmetry axis that divides the inner region of the second conductor loop 1y into line symmetry.
The second conductor loop 1y is disposed along a second surface including a line symmetry axis that divides the inner region of the third conductor loop 1z in line symmetry.

The line symmetry axis here is a geometric line symmetry axis and need not be accompanied by an entity.
Arranging along the surface ideally means that each part of the conductor loop exists at any position on the surface.

Furthermore, in the example of FIG. 1, the third conductor loop 1 z is disposed along a third plane including a line symmetry axis that divides the inner region of the first conductor loop 1 x in line symmetry.
The inner region, the line symmetry axis, and each surface are not shown.

  The triaxial loop antenna includes a cube 1. The first conductor loop 1x includes the center 11c of the first surface 11 of the cube 1, the center 12c of the second surface 12 perpendicular to the first surface 11, the center of the third surface 13 parallel to the first surface 11, the second Arranged along the center of the fourth surface 14 parallel to the surface 12.

  The second conductor loop 1y includes the center 15c of the fifth surface 15 perpendicular to the first surface 11, the center 12c of the second surface 12, the center of the sixth surface parallel to the fifth surface 15, and the center of the fourth surface 14. It is arranged along. The third conductor loop 1z is disposed along the center 11c of the first surface, the center of the sixth surface 16, the center of the third surface 13, and the center 15c of the fifth surface 15.

Specifically, in the cube 1 formed of an insulator, three grooves 2 passing through the centers of the respective surfaces (11 to 16) are formed in a loop shape. In each groove 2, a conductor loop (1x, 1y, 1z) covered with an insulator is wound. Although the number of turns in FIG. 1 is one, the number of turns may be multiple. The three conductor loops arranged in this way are orthogonal to each other, and the centers of the three conductor loops coincide. In this case, since the magnetic flux generated by the current flowing through any conductor loop does not penetrate through the other conductor loop, no current flows through the other conductor loop due to this magnetic flux. In other words, the mutual inductance between the conductor loops is ideally zero. Therefore, erroneous detection of different magnetic field components does not occur as occurs in the conventional triaxial loop antenna shown in FIG. That is, the magnetic field can be detected with high accuracy.
The same effect can be obtained even when the cube 1 is replaced with a rectangular parallelepiped.

[Second Embodiment]
A triaxial loop antenna according to the second embodiment is shown in FIG.
The triaxial loop antenna includes conductor loops 1x, 1y, and 1z arranged along each of three surfaces that are perpendicular to each other in space.

  The conductor loops 1x, 1y, and 1z are arranged along a plane perpendicular to the x-axis, a plane perpendicular to the y-axis, and a plane perpendicular to the z-axis, respectively.

The first conductor loop 1x is disposed along a first surface including a line symmetry axis that divides the inner region of the second conductor loop 1y into line symmetry.
The second conductor loop 1y is disposed along a second surface including a line symmetry axis that divides the inner region of the third conductor loop 1z in line symmetry.
The inner region, the line symmetry axis, and each surface are not shown.

  Specifically, the three-axis loop antenna includes a square or rectangular first substrate 2x having a first conductor loop 1x as a substrate pattern, and a square or rectangular second substrate having a second conductor loop 1y as a substrate pattern. 2y and a square or rectangular third substrate 2z having the third conductor loop 1z as a substrate pattern.

  The first end surface 21x of the first substrate 2x faces the one surface 21y of the second substrate 2y, and the second end surface 22x of the first substrate 2x perpendicular to the first end surface 21x of the first substrate 2x is the third. The first end surface 22z of the third substrate 2z faces the one surface 21y of the second substrate 2y.

The term “facing” ideally means a state in which the end face is parallel to the surface, and may or may not be in contact.
The conductor loop has a rectangular shape, for example.

FIG. 3 shows a plan view of the first substrate 2x, the second substrate 2y, and the third substrate 2z.
In the inner region of the conductor loop 1y formed on the second substrate 2y, there are line symmetry axes A and B that divide the inner region into line symmetry. A first end face 21x of the first substrate 2x is arranged along the line symmetry axis A. Along the line symmetry axis B, the end face 22z of the third substrate 2z is disposed.

  In the inner region of the conductor loop 1z formed on the third substrate 2z, there is a line symmetry axis C that divides the inner region into line symmetry. A first substrate 2x is arranged along the line symmetry axis C.

  In order to stand the first substrate 2x and the third substrate 2z vertically on the second substrate 2y, the first substrate 2x and the third substrate 2z have projections m, and the projections m on the second substrate 2y. A hole n for inserting a hole is formed.

  In the second embodiment, since the magnetic flux generated by the current flowing through the conductor loop does not penetrate the other conductor loop, the mutual inductance is ideally zero. Therefore, the magnetic field can be detected with high accuracy.

[Third embodiment]
A triaxial loop antenna according to a third embodiment is shown in FIG.
The third embodiment is similar to the second embodiment, but the feed line f connected to the first conductor loop 1x and the third conductor loop 1z is connected to one surface of the second substrate 2y. Since it is formed in 21y, the terminals of each conductor loop can be arranged together in a narrow area. This makes it easy to connect the end of the conductor loop to an amplifier or the like. Further, as in the second embodiment, the mutual inductance of each conductor loop is ideally zero, so that the magnetic field can be detected with high accuracy.

[Fourth embodiment]
A triaxial loop antenna according to a fourth embodiment is shown in FIG.
The fourth embodiment is similar to the second embodiment, but a slit 24x is formed on the first end face 21x of the first substrate 2x toward the second end face 23x parallel to the end face 21x. In addition, the slit 24x is disposed so that the peripheral portion thereof straddles the third substrate 2z.

  Therefore, a part of the first conductor loop 1x is formed on the second substrate 2y. Similar to the second embodiment, since the mutual inductance of each conductor loop is ideally zero, the magnetic field can be detected with high accuracy.

[Fifth embodiment]
A triaxial loop antenna according to a fifth embodiment is shown in FIG.
The fifth embodiment is similar to the second embodiment, but all of the first conductor loops 1x are formed on the first substrate 2x. Similar to the fourth embodiment, since the mutual inductance of each conductor loop is ideally zero, the magnetic field can be detected with high accuracy.

[Sixth embodiment]
A triaxial loop antenna according to a sixth embodiment is shown in FIG.
The triaxial loop antenna according to the sixth embodiment is obtained by making the number of windings of the conductor loops 1x, 1y, and 1z a plurality of times in the fifth embodiment. Similar to the fifth embodiment, since the mutual inductance of each conductor loop is ideally zero, the magnetic field can be detected with high accuracy.

  In the second to sixth embodiments, the shape of each conductor loop may be any shape as long as it has a line symmetry axis, such as a rectangle, a square, an ellipse, or a circle.

DESCRIPTION OF SYMBOLS 1 ... Cube 1x ... 1st conductor loop 1y ... 2nd conductor loop 1z ... 3rd conductor loop 2 ... Groove 2x ... 1st board | substrate 2y ... 2nd board | substrate 2z ... 3rd board | substrate 11 ... 1st surface 11c, 12c 15c ... Center 12 ... Second surface 13 ... Third surface 14 ... Fourth surface 15 ... Fifth surface 16 ... Sixth surface 21x, 22x, 22z, 23x ... End surface 21y, 21z ... Surface 24x ... Slit A, B, C ... Axis of symmetry

Claims (3)

In a three-axis loop antenna comprising a conductor loop disposed along each of three surfaces that are perpendicular to each other in space,
The first conductor loop is disposed along the first surface including a line symmetry axis that divides the inner region of the second conductor loop in line symmetry;
The second conductor loop is disposed along the second surface including a line symmetry axis that divides the inner region of the third conductor loop in line symmetry ;
A square or rectangular first substrate having the first conductor loop as a substrate pattern;
A square or rectangular second substrate having the second conductor loop as a substrate pattern;
A third substrate having a square or rectangular shape having the third conductor loop as a substrate pattern,
A first end surface of the first substrate is opposed to one surface of the second substrate;
A second end surface of the first substrate perpendicular to the first end surface of the first substrate faces one surface of the third substrate;
Triaxial loop antenna first end surface of the third substrate, wherein the you face the one surface of the second substrate. The triaxial loop antenna according to claim 1, wherein a feed line connected to the first conductor loop and the third conductor loop is formed on one surface of the second substrate. In a three-axis loop antenna comprising a conductor loop disposed along each of three surfaces that are perpendicular to each other in space,
The first conductor loop is disposed along the first surface including a line symmetry axis that divides the inner region of the second conductor loop in line symmetry;
The second conductor loop is disposed along the second surface including a line symmetry axis that divides the inner region of the third conductor loop in line symmetry ;
A first substrate having a square or rectangular shape, wherein a first end surface of the substrate is formed with a slit toward a second end surface parallel to the end surface, and the first substrate has the first conductor loop as a substrate pattern;
A square or rectangular second substrate having the second conductor loop as a substrate pattern;
A third substrate having a square or rectangular shape having the third conductor loop as a substrate pattern,
The first end surface of the first substrate is opposed to one surface of the second substrate, and the peripheral portion of the slit of the first substrate is disposed across the third substrate,
Triaxial loop antenna first end surface of the third substrate, wherein the you face the one surface of the second substrate.

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