Three-axis antenna with improved quality factor

Abstract

Three-axis antenna comprising a magnetic core (10) including protuberances (11) on each corner delimiting an X-axis winding channel (12X) and a Y-axis winding channel (12Y); in X-axis coil (20X) within the X-axis winding channel (12X), comprising two separate and adjacent X-axis partial coils (21X); a Y-axis coil (20Y) within the Y-axis winding channel (12Y), comprising two separate and adjacent Y-axis partial coils (21Y); and a Z-axis coil (20Z) surrounding the magnetic core (10), wherein said magnetic core includes at least one X-axis partition wall (14X) dividing the X-axis winding channel (12X) in two X-axis partial winding channels (13X) wherein the two separate and adjacent Y-axis partial coils (21Y) are housed, and at least one Y-axis partition wall (14Y) dividing the Y-axis winding channel (12Y) in two Y-axis partial winding channels (13Y) wherein the two separate and adjacent Y-axis partial coils (21Y) are housed.

Claims

1. A three-axis antenna with an improved quality factor comprising: a magnetic core (10) having a prismatic configuration defining an X-axis (X), a Y-axis (Y), and a Z-axis (Z) orthogonal to one another, said prismatic configuration being a rectangular prismatic configuration having two main faces perpendicular to each of the X-axis (X), Y-axis (Y) and Z-axis (Z), said prismatic configuration including protuberances (11) protruding on the Z-axis (Z) direction on each corner of the magnetic core (10), said protuberances (11) delimiting an X-axis winding channel (12X) and a Y-axis winding channel (12Y) around the magnetic core (10); an X-axis coil (20X) wound around the X-axis (X) surrounding the magnetic core (10) within the X-axis winding channel (12X), said X-axis coil (20X) comprising two separate and adjacent X-axis partial coils (21X); a Y-axis coil (20Y) wound around the Y-axis (Y) surrounding the magnetic core (10) within the Y-axis winding channel (12Y), said Y-axis coil (20Y) comprising two separate and adjacent Y-axis partial coils (21Y); a Z-axis coil (20Z) wound around the Z-axis (Z) surrounding the magnetic core (10), wherein the X-axis winding channel (12X) intersects the Y-axis winding channel (12Y) on two opposed intersection areas in which the Y-axis winding channel (12Y) is interrupted by the X-axis winding channel (12X) defined at a lower level; wherein said protuberances (11) are also protruding on the X-axis (X) and on the Y-axis (Y) directions defining an outer perimeter around of which there is wind the Z-axis coil (20Z) without interfering with the X-axis coil (20X) and the Y-axis coil (20Y), said magnetic core (10) includes: at least one X-axis partition wall (14X) protruding from the X-axis winding channel (12X) dividing the X-axis winding channel (12X) in two X-axis partial winding channels (13X) wherein the two separate and adjacent X-axis partial coils (21X) are housed, said X-axis protruding wall not interfering with the Y-axis winding channel (12Y); and at least one Y-axis partition wall (14Y) protruding from the Y-axis winding channel (12Y) dividing the Y-axis winding channel (12Y) in two Y-axis partial winding channels (13Y) wherein the two separate and adjacent Y-axis partial coils (21Y) are housed; a Z-axis wall (14Z) included in the outer perimeter of the magnetic core (10) and protruding in the X-axis (X) and/or the Y-axis (Y) directions, providing a magnetic core having an un-moldable geometry easily un-moldable from a two parts cast.

2. The three-axis antenna according to claim 1, wherein the X-axis partition wall (14X) are protruding on the Y-axis (Y) direction and/or on the Z-axis (Z) direction.

3. The three-axis antenna according to claim 1, wherein the Y-axis partition wall (14Y) are protruding on the X-axis (X) direction and/or on the Z-axis (Z) direction.

4. The three-axis antenna according to claim 1, wherein the X-axis partition wall (14X) is a continuous wall which extends around four adjacent faces of the magnetic core (10).

5. The three-axis antenna according to claim 1, wherein the Y-axis partition wall (14Y) are two independent and symmetric walls, each extending continuously around three adjacent faces of the prismatic core (10), being said two independent and symmetric walls spaced apart by the X-axis winding channel (12X).

6. The three-axis antenna according to claim 1 wherein the X-axis partition wall (14X) and/or the Y-axis partition wall (14Y) are equidistant from the protuberances (11).

7. The three-axis antenna according to claim 1 wherein the Z-axis wall (14Z) is placed on the center of the outer perimeter defining two symmetric Z-axis partial wounding channels (13Z) defining together the Z-axis wounding channel (12Z), and wherein the Z-axis coil (20Z) wound around the Z-axis (Z) comprises two separate and adjacent Z-axis partial coils (21Z) each wound in one different Z-axis partial wounding channels (13Z).

8. The three-axis antenna according to claim 1 wherein the Z-axis wall (14Z) is protruding in a non-centered position of the outer perimeter, being the Z-axis coil (20Z) wound around the Z-axis (Z) on one side of the Z-axis wall (14Z) which define one winding limit for said Z-axis coil (20Z).

9. The three-axis antenna according to claim 8 wherein a Z-axis additional wall (15Z) is protruding in a non-centered position of the outer perimeter, being said Z-axis additional wall (15Z) symmetric to the Z-axis wall (14Z) defining a Z-axis winding channel (12Z) there between, and being the Z-axis coil (20Z) housed on said Z-axis winding channel (12Z).

10. The three-axis antenna according to claim 1 wherein said magnetic core (10) is made of a material selected among ferromagnetic material, PBM (polymer-bonded soft magnetic material), pressed and sintered metallic powder.

11. The three-axis antenna according to claim 1 wherein between the X-axis, Y-axis and Z-axis coils (20X, 20Y, 20Z) and the magnetic core (10) there is an electric insulant material.

12. The three-axis antenna according to claim 11 wherein said electric insulant material is a chemical vapor deposited polymer.

13. The three-axis antenna according to claim 1 wherein the three-axis antenna is over-molded with an insulant material, said insulant material including metallic connection terminals (30) embedded therein, being each metallic connection terminals (30) connected to one end of one wire constitutive of one partial coil (21X, 21Y, 21Z), and having each metallic connection terminal (30) a portion non-covered by the insulant material accessible from the outside of the three-axis antenna cover.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The foregoing and other advantages and features will be more fully understood from the following detailed description of an embodiment with reference to the accompanying drawings, to be taken in an illustrative and not limitative, in which:

(2) FIG. 1 is a perspective view of a magnetic core according to a first embodiment of the present invention;

(3) FIG. 2 is a perspective view of the same magnetic core shown on FIG. 1 having X-axis coil, Y-axis coil and Z-axis coil wound therearound, including also metallic connection terminals;

(4) FIG. 3 is a perspective view of a magnetic core according to a second embodiment of the present invention;

(5) FIG. 4 is a perspective view of the same magnetic core shown on FIG. 3 having X-axis coil, Y-axis coil and Z-axis coil wound therearound;

(6) FIG. 5 is a plant view of a magnetic core according to a third embodiment;

(7) FIG. 6 is a lateral view of the magnetic core shown on FIG. 5;

(8) FIG. 7 is a transversal section of the magnetic core shown on FIG. 5 across the Z-axis winding channel.

DETAILED DESCRIPTION

(9) The foregoing and other advantages and features will be more fully understood from the following detailed description of an embodiment with reference to the accompanying drawings, to be taken in an illustrative and not limitative, in which:

(10) According to a first embodiment of the three-axis antenna, the magnetic core 10 is obtained from a pressed and sintered metallic powder. Said magnetic core 10 is produced in a two-part cast thanks to its geometry, which permits an easy cast extraction from a two-parts cast. In an alternative embodiment, another material for the core could be use, preferably a ferromagnetic material, PBM (polymer-bonded soft magnetic material). The shape of the magnetic core 10, shown in FIG. 1, is a prismatic configuration defining an X-axis X, a Y-axis Y and a Z-axis Z, orthogonal to each other, and having two main faces perpendiculars to the Z-axis with four corners.

(11) On each corner, a protuberance 11 protrudes from said magnetic core 10, said four protuberances 11 protruding on both main faces of the magnetic core 10, said protuberances 11 extending in radial direction outwards of the prismatic configuration defining an outer perimeter of the magnetic core 10.

(12) On each main face of the magnetic core 10, between the four protuberances 11, two perpendicular winding channels 12X and 12Y are created. The X-axis winding channel 12X crosses both main faces. The space defined between two adjacent protuberances 11 not occupied by the X-axis winding channel 12X includes an elevated surface which creates a stepped configuration with the X-axis winding channel 12X. Said elevated surface defines the Y-axis winding channel 12Y which is in a different height regarding the X-axis winding channel 12X.

(13) The perimetric faces of the magnetic core 10 are those faces which connect the main faces of the magnetic core 10, placed in its perimeter and including the outer perimeter of the magnetic core 10.

(14) As stated before the protuberances 11 protrude in radial directions (X-axis X and Y-axis Y directions). Between the protuberances 11 protruding in radial directions are defined a portion of the X-axis winding channel 12X and of the Y-axis winding channel 12Y, said portions being defined on the perimeter surfaces of the magnetic core 10.

(15) The X-axis winding channel 12X includes, on its center, an X-axis partition wall 14X which, in this embodiment is an annular and continuous wall surrounding the magnetic core 10.

(16) Said X-axis partition wall 14X is a protrusion of the magnetic core 10, and defines two X-axis partial winding channels 13X, one on each side.

(17) The Y-axis winding channel 12Y also includes on its center a Y-axis partition wall 14Y which, in this embodiment, are two independent and coplanar walls each covering three faces of the magnetic core 10, said Y-axis partition wall 14Y being a protrusion of the magnetic core 10 and defining two Y-axis partial winding channels 13Y, one on each side.

(18) The outer perimeter of the magnetic core 10, defined by external surfaces of the protuberances 11, also includes a Z-axis wall 14Z protruding from the magnetic core 10 which, in this embodiment, includes four coplanar walls, one on each protuberance 11, centered on the outer perimeter defining two Z-axis partial winding channels 13Z, one on each side.

(19) On FIG. 2 it is shown how, on each X-axis partial winding channel 13X, an X-axis partial coil 21X is wound, the two X-axis partial coils 21X creating together an X-axis coil 20X surrounding the magnetic core 10.

(20) Also, on each Y-axis partial winding channel 13Y, a Y-axis partial coil 21Y is wound, the two Y-axis partial coils 21Y creating together a Y-axis coil 20Y surrounding the magnetic core 10.

(21) Finally, on each Z-axis partial winding channel 13Z, a Z-axis partial coil 21Z is wound, the two Z-axis partial coils 21Z creating together a Z-axis coil 20Z surrounding the magnetic core 10.

(22) Then metallic connection terminals 30 are disposed around the three-axis antenna, each metallic connection terminal 30 being connected to one end of a wire constitutive of a partial coil 21X, 21Y, 21Z.

(23) As shown in FIG. 2 each metallic connection terminal 30 is attached to the magnetic core 10 for example by an adhesive on each of the protuberances 11 and provides portions for a surface mounting connection, acting as a surface mounting pads.

(24) Additionally, an over-molded cover will be then created around the three-axis antenna leaving parts of all the metallic connection terminals 30 exposed for the electric connection of the antenna created to a circuit. This over-molded cover has not been indicated in the drawings.

(25) According to an alternative embodiment shown in FIG. 3, the X-axis partition wall 14X can be non-continuous and non-annular.

(26) The Z-axis partition wall 14Z is, in this embodiment, placed on a non-centered position of the outer perimeter, defining a Z-axis winding channel 12Z only on one side thereof, in which a single Z-axis coil 20Z will be wound, as shown in FIG. 4.

(27) In an additional alternative shown in FIGS. 5, 6 and 7, the X-axis partition walls 14X are projected only on the Y-axis Y direction, and the Y-axis partition walls 14Y are protruding only on the X-axis X direction, both protruding from the perimeter surfaces of the magnetic core 10 and not from the main faces of the magnetic core 10.

(28) In this embodiment the Z-axis wall 14Z projects from the outer perimeter of the protuberances 11 in a non-centered position, and a Z-axis additional wall 15Z projects also from the outer perimeter in a non-centered position symmetric from the previously mentioned Z-axis wall 14Z regarding a central plan of the magnetic core 10 perpendicular to the Z-axis Z.

(29) Between the Z-axis wall 14Z and the Z-axis additional wall 15Z the Z-axis winding channel 12Z is defined, wherein a single Z-axis coil 20Z will be wound.

(30) The shape of the magnetic core 10 described on this last embodiment cannot be produced in a two parts cast because of the shape of the Z-axis winding channel 12Z contained between two walls facing each other, and because of the shape of the other winding channels 12X and 12Y also contained between faces facing each other on orthogonal directions.

(31) In this case the magnetic core 10 can be produced, for example, by pressing metallic powder in a cast which creates the general shape of the magnetic core 10 lacking the Z-axis winding channel 12Z. Then the magnetic core 10 is extracted and the Z-axis winding channel 12Z is milled in the magnetic core 10 before or after the sintering process which solidifies the metallic powder constitutive of the magnetic core 10. A high-pressure mold injection process and subsequent sintering can be used in an alternative.

(32) In any of the previous embodiments, said magnetic core 10 can be covered with an insulant material previous to winding the X-axis, Y-axis and Z-axis coils 20X, 20Y and 20Z. Preferably said insulant material is a chemical vapor deposited polymer which produces an ultra-thin insulating layer.

(33) It will be understood that various parts of one embodiment of the invention can be freely combined with parts described in other embodiments, even being said combination not explicitly described, provided there is no harm in such combination.