EP3525286B1 - Ferrite rod antenna and transmitting and receiving unit with corresponding ferrite rod antenna - Google Patents

Description

The present invention relates to a ferrite rod antenna and a transmitting and receiving unit with a ferrite rod antenna.

In general, a ferrite rod antenna refers to a magnetic antenna in which a coil is attached to a ferrite rod. The B-field component of an electromagnetic wave induces a voltage in the coil that is tapped.

Ferrite rod antennas are mainly used for short-range communication, but ferrite rod antennas are also suitable in radio and radio technology for the reception of long, medium or possibly also short waves, especially for the reception of radio waves with frequencies below 2 MHz. However, since ferrite rod antennas are less efficient than loop antennas and, due to their shape, have a high degree of directional sensitivity, they are only suitable to a limited extent as transmission antennas, at best for low transmission powers.

Applications for ferrite rod antennas arise, for example, in RFID (radio frequency identity) technology, such as opening cars without a key or in search devices that are used, for example, to locate buried subjects in the alpine area. Tourers carry a small device with them that is operated in transmit mode. If a skier is buried in an avalanche, group members can switch the identical device that they are carrying with them from a transmit mode to a receive mode in order to locate the buried victim by bearing.

The pamphlet EP1439400 A2 shows a search device for locating people buried in avalanches, with three orthogonal ferrite rod antennas housed in a compact housing and connected to a receiving unit. In a transmission mode, a ferrite rod antenna is connected to a transmission unit, while in a reception mode the three orthogonal ferrite rod antennas are alternately connected to a reception unit.

document US 6134420 shows a wireless communication system with a receiving device with a single wound rod core and a transmitting device with an orthogonally wound rod core, the winding of which is perpendicular to the winding of the rod core of the receiving device. Alternatively, a triple orthogonally wound spherical core is disclosed.

document WO 2012/120302 A1 discloses a system for providing course information with a three-fold orthogonally wound cube-shaped core as a transmitting and receiving device.

From scripture U.S. 3,750,180 a magnetic antenna having a plate-shaped magnetic core in which two openings are formed is known. Here, two windings are formed at the openings with winding axes perpendicular to one another. The winding of the magnetic core is difficult because the winding wire has to be threaded through the openings.

The one in Scripture DE 10 2013 113 244 A1 The subject described relates to a coil arrangement for an inductive energy transmission system, which has at least one plate-shaped coil core made of ferrite. The at least one plate-shaped coil core is surrounded by at least one winding each with at least one turn, the coil arrangement having at least two windings, the winding axes of which are arranged at an angle of greater than 50 ° to one another. The turns of the windings arranged at an angle to one another are arranged without crossing one another. Crossing turns cross their windings only in the area of a recess or an area with a reduced thickness of the plate-shaped coil core.

The font WO 2015/194036 A1 describes an antenna device with a core. The core has a first leg portion and a second leg portion which extend in opposite directions relative to one another, and a third leg portion which extends in a direction perpendicular to the direction of extension of the first leg portion and the second leg portion from a middle portion between the first leg portion and the second Leg portion extends. The antenna device is also provided with a first coil formed by connecting in series a first small coil wound on the first leg portion and a second small coil wound on the second small leg portion. The antenna device also includes a first signal source that supplies power to the first coil, a second coil that is wound on the third leg portion, and a second signal source that supplies power to the second coil.

From scripture WO 2017/183934 A1 a three-axis antenna module with a keyless entry system is known which has three coils which are respectively arranged wound around an X-axis, a Y-axis and a Z-axis, which are mutually orthogonal, and which further comprises a magnetic core consisting of a magnetic material and at least one receiving space formed therein for receiving one around the Having a first coil wound around the X-axis and a second coil wound around the Y-axis. The magnetic core supports a third coil wound around the Z-axis along the circumferential direction. Furthermore, a plurality of connections are provided which are formed on at least one surface of the magnetic core in order to enable an electrical connection to the outside.

In scripture US 6,407,677 B1 there is shown a device for low frequency communication by magnetic coupling of the type having a magnetic field transmitter and a receiver located in an identification element, the transmitter or the receiver being provided with a loop antenna, the other being composed of either the transmitter or the receiver is formed by the union of three coils wound around three perpendicular axes defining a tetrahedron, so that an omnidirectional magnetic field is obtained by supplying the coils with currents of the same frequency.

Since the requirements for a good transmitting antenna and a good receiving antenna are contradictory (a transmitting antenna should primarily be elongated, while a receiving antenna should have as large an area as possible perpendicular to the received field lines), known ferrite rod antennas are used for transmitting and also for the Reception operation are provided, either with regard to the transmission power or the reception power is an unacceptable compromise with modern requirements. Furthermore, with known multiply wound cores for ferrite rod antennas, there is the problem that one winding is in the stray field of at least one other winding. In addition, in known cores with multiple coils for ferrite rod antennas, there is at least one winding which has a high DC resistance.

In view of the above-mentioned problems, it is an object to provide a ferrite rod antenna for use as a transmitting and receiving antenna with sufficient receiving power and transmitting power that meets modern requirements.

The above-mentioned problems and objects are achieved by a ferrite rod antenna according to claim 1 and a ferrite rod antenna according to claim 6. Advantageous embodiments are defined in the dependent claims 2 to 5.

Furthermore, the above-mentioned problems and objects are achieved by a transmitting and receiving unit according to claim 7 with a corresponding ferrite rod antenna.

In a first aspect of the invention there is provided a ferrite rod antenna having a ferrite core having a first ferrite core portion, a second ferrite core portion and a third ferrite core portion, the first ferrite core portion and the third Ferrite core portion are spaced apart from one another by the second ferrite core portion. The ferrite core is at least partially tapered at the second ferrite core section relative to the first and third ferrite core sections in at least one direction. The ferrite rod antenna furthermore has a first winding which is arranged over the first ferrite core section and / or the third ferrite core section and defines a first winding axis, and a second winding which is arranged over the second ferrite core section and a second Defines winding axis that is not parallel to the first winding axis, the ferrite core has a smallest dimension on the second ferrite core section in a direction parallel to the first winding axis relative to the first and third ferrite core sections.

The ferrite core provided in the first aspect of the invention enables a compact design of a ferrite rod antenna which is suitable for transmitting and receiving magnetic fields. As a result of the second ferrite core section which is tapered relative to the first and third ferrite core sections, the second winding is provided with a low direct current resistance. In addition, the taper in the second ferrite core section enables the second winding to be arranged above the ferrite core, so that the second winding is influenced to a minimal extent by stray fields caused by the first winding, despite a compact design of the ferrite core and a multiple winding provided above it . Due to the taper, which is formed in the contour of the ferrite core in such a way that a dimension of the ferrite core in a direction parallel to the first winding axis is smallest relative to the first and third ferrite core sections, a winding on the second ferrite core section can advantageously be included in the contour. It is therefore easy to wrap the ferrite core on the second ferrite core section. Furthermore, the tapering at the second ferrite core section leads to a concentration of the magnetic flux density at the second ferrite core section and thus to an increase in the winding provided around the second ferrite core section. The ferrite rod antenna thus has improved properties as a receiving antenna.

The first aspect can be exemplified by a ferrite rod antenna comprising a ferrite core formed by at least three ferrite core sections. The ferrite core sections can be designed as individual elongated ferrite rods, two of these elongated ferrite rods having a first length dimension that is greater than a second length dimension of the other of the three elongated ferrite rods, for example the first length dimension can be at least a factor of "1.5" or be at least a factor "2" or at least a factor "3" or at least a factor "5" greater than the second length dimension. In the ferrite core, the elongated ferrite rod with the second length dimension is arranged perpendicular or substantially perpendicular to the two elongated ferrite rods with the first length dimension, so that they are spaced apart from one another by the elongate ferrite rod with the second length dimension. According to specific illustrative examples herein, the two elongated ferrite rods with the first length dimension can be arranged parallel to one another and the ferrite core can have an H-shaped configuration in a side view of the three ferrite rods. The ferrite rod having the second length dimension is formed in a cylindrical shape.

Furthermore, the ferrite core has an elongated shape which defines a longitudinal direction. A dimension of the second ferrite core section is smaller at least along the longitudinal direction than a dimension of the first ferrite core section along the longitudinal direction and / or a dimension of the third ferrite core section along the longitudinal direction. A taper in the ferrite core on the second ferrite core section is thereby provided in a simple manner.

In addition, the ferrite rod antenna is configured such that the first and third ferrite core sections are spaced apart from each other along a connection direction perpendicular to the longitudinal direction of the first and third ferrite core sections by the second ferrite core section and a dimension of the second ferrite core section in a width direction perpendicular to the longitudinal direction and perpendicular to the connection direction is less than or equal is a smallest dimension of dimensions of the first and third ferrite core portions in their respective width directions. This provides a second ferrite core section which enables a small cross-sectional area and consequently a concentration of the B field lines in the second ferrite core section in a receiving mode, with a direct current resistance of the second winding also being kept low due to the small cross section.

Furthermore, the ferrite rod antenna is designed such that the second ferrite core section has a cylindrical shape, the first and third ferrite core sections are arranged on opposite end faces of the second ferrite core section, and the second winding is arranged over part of a lateral surface of the second ferrite core section. This provides a simple way of providing a compact ferrite rod antenna with a transmitting coil and a receiving coil.

In a first embodiment of the ferrite rod antenna of the first aspect, the ferrite rod antenna is designed such that the first winding axis is oriented parallel to the longitudinal direction. As a result, the first winding provides an advantageous radiation characteristic for the ferrite rod antenna along the longitudinal direction.

In a second embodiment of the ferrite rod antenna of the first aspect, the ferrite rod antenna is further designed such that the first and third ferrite core sections are spaced apart from one another along a connecting direction perpendicular to the longitudinal direction of the first and third ferrite core sections by the second ferrite core section. This provides a simple geometric arrangement of the first to third ferrite core sections, the second ferrite core section being able to be wound along a direction which is oriented perpendicular to the longitudinal direction. In this way, surfaces with surface normals which are oriented perpendicular to the longitudinal direction can advantageously be used for receiving the B-field component of electromagnetic radiation.

In a third embodiment of the ferrite rod antenna of the first aspect, the first winding is arranged over areas of a lateral surface of the ferrite rod antenna at opposite ends of the ferrite rod antenna on the first and third ferrite core sections, with in particular end faces of the ferrite rod antenna and the second ferrite core section being exposed with respect to the first winding. As a result, the end faces of the ferrite rod antenna can be used effectively for radiation in a transmission mode of the ferrite rod antenna.

In a fourth embodiment of the ferrite rod antenna of the first aspect, the first ferrite core section and the third ferrite core section have at least one rounded edge as a support surface for the first winding. This provides an advantageous embodiment of the first and third ferrite core sections in order to simply wind the ferrite core reliably and in a manner suitable for machine production.

In a fifth embodiment of the ferrite rod antenna of the first aspect, the first ferrite core section and the third ferrite core section each have a recess in which the second ferrite core section is partially received. This provides a simple and reliable configuration for the ferrite core which is modularly formed from the first to third ferrite core sections. For example, ferrite cores with different dimensions can be manufactured in production by providing appropriately sized first to third ferrite core sections and assembled in a modular manner with a view to a special application.

In a second aspect, ferrite rod antenna is provided, comprising a ferrite core which is formed by at least five interconnected ferrite rods, and a first winding and a second winding, which are each arranged over the ferrite core, wherein four ferrite rods of the at least five ferrite rods have a first length dimension and the other ferrite rod of the at least five ferrite rods has a second length dimension which is smaller than the first length dimension, the four ferrite rods with the first length dimension each being arranged parallel to one another on the ferrite rod with the second length dimension and through the ferrite rod with the second length dimension in each case to one another are spaced. The ferrite rod is arranged with the second length dimension perpendicular or substantially perpendicular to the four ferrite rods with the first length dimension and the first winding is arranged over the ferrite rods with the first length dimension, while the second winding is arranged over the ferrite rod with the second length dimension, wherein the ferrite core has an H-shaped shape in a side view of the five ferrite rods.

In a third aspect, a transmitting and receiving unit with the ferrite rod antenna according to the first or the second aspect is provided, further comprising a electronic transmitter circuit which is electrically connected to the winding, and an electronic receiver circuit which is electrically connected to at least the second winding. A transmission and reception unit with improved reception performance is provided, which can be implemented in a compact design without the transmission performance or reception performance being significantly impaired at the expense of the reception performance or transmission performance.

Fig. 1

schematisch eine perspektivische Ansicht einer Ferritstabantenne gemäß anschaulicher Ausführungsformen der Erfindung darstellt;

Fig. 2

schematisch eine perspektivische Ansicht einer Ferritstabantenne gemäß anderer anschaulicher Ausführungsformen der Erfindung darstellt;

Fig. 3

schematisch eine Konfiguration zweier Ferritkernabschnitte eines Ferritkerns gemäß einiger Ausführungsformen der Erfindung darstellt; und

Fig. 4

schematisch ein Schaltbild einer Sende- und Empfangseinheit gemäß anschaulicher Ausführungsformen der vorliegenden Erfindung darstellt.

Further advantages and features of the invention emerge from the following description of specific embodiments of the invention, wherein:

Fig. 1

schematically depicts a perspective view of a ferrite rod antenna in accordance with illustrative embodiments of the invention;

Fig. 2

schematically depicts a perspective view of a ferrite rod antenna in accordance with other illustrative embodiments of the invention;

Fig. 3

schematically illustrates a configuration of two ferrite core portions of a ferrite core according to some embodiments of the invention; and

Fig. 4

schematically represents a circuit diagram of a transmitting and receiving unit according to illustrative embodiments of the present invention.

For the transmitted B field of a ferrite rod antenna at a certain distance z along a longitudinal direction of the ferrite rod antenna, taking into account the relationship B̂ ( z ) = 1 / (2 π ) · φl / z ^3, the following equation Eq. 1 to: $$\widehat{\mathrm{B.}}\left(z\right)=\frac{1}{\pi }\sqrt{\frac{{\mu }_0}{2}}\cdot \frac{\mathrm{<figure-callout\; id="3"\; label="I.\; L.\; z"\; filenames="imgf0001.png"\; state="\{\{state\}\}">I.</figure-callout>}\sqrt{\mathrm{L.}}}{z^{}}\cdot {\mathrm{A.}}^{0.15}{l}^{1.2}$$

Here Φ denotes the magnetic flux, I the current intensity, L the inductance of a transmitter coil of the ferrite rod antenna, A the magnetic cross section, l the length of the ferrite core of the ferrite rod antenna and B the magnetic flux density transmitted along the longitudinal direction.

For upon reception of a B-field in a coil of the ferrite bar antenna induced voltage U is of the inventors in consideration of the transformer formula U = 2 πBANf, wherein the frequency of the received field, and N f is the number of turns of the receiver coil designated, the following equation Eq. 2 to: $$Û\left(z\right)=\mathrm{<figure-callout\; id="2"\; label="\pi "\; filenames="imgf0003.png"\; state="\{\{state\}\}">\pi </figure-callout>}\sqrt{\frac{2}{{\mu }_0}}\cdot \mathrm{B.}\left(z\right)f\sqrt{\mathrm{L.}}\cdot \frac{{\mathrm{A.}}^{0.85}}{l^{0.2}}$$

Using Eq. 1 it can be seen that a ferrite rod antenna for good transmission characteristics should primarily have the largest possible value for l due to the exponents of A and l , if the remaining parameters are assumed to be fixed. Using Eq. 2, however, it can be seen that a ferrite rod antenna should have the largest possible area A perpendicular to the field lines for good reception characteristics.

As a result, the criteria for an optimal transmitting antenna are the opposite of an optimal receiving antenna.

In view of the above findings, the invention provides a ferrite rod antenna which, based on a core design according to the invention for the ferrite core of the ferrite rod antenna, allows the transmission characteristics and the reception characteristics to be optimized.

Below are some illustrative embodiments with reference to FIG Fig. 1 described. It shows Fig. 1 a ferrite rod antenna 1 with a ferrite core, the first Ferrite core section 3, a second ferrite core section 5 and a third ferrite core section 7. The first ferrite core section 3 and the third ferrite core section 7 are spaced apart from one another by the second ferrite core section 5. The first ferrite core section 3 and the third ferrite core section 7 have an elongated shape so that they each define a longitudinal direction. Furthermore, the first ferrite core section 3 and the third ferrite core section 7 are oriented to one another in such a way that both longitudinal directions are oriented in parallel and thus only one longitudinal direction is defined overall by the first ferrite core section 3 and the third ferrite core section 7.

A first winding W1, which defines a first winding axis A1, is arranged above the first ferrite core section 3 and the third ferrite core section 7. For example, the winding axis A1 represents a direction which is rotated by the individual turns of the first winding W1 and which is oriented parallel to a pitch between two successive turns of the first winding W1. In an illustrative example, the first winding axis A1 represents a normal to a plane in which one turn of the first winding W1 lies (here, one turn of a winding is understood to mean a complete azimuthal revolution of 2π). In other words, the first winding axis A1 represents an axis of symmetry of the first winding W1 with respect to a rotation in a winding plane or a projection of a winding plane onto a plane which is oriented orthogonally to a pitch between adjacent windings of the first winding W1. The first winding axis A1 runs in particular along the longitudinal direction of the first and third ferrite core sections 3, 7.

In Fig. 1 the first winding W1 is shown as being arranged above the first ferrite core section 3 and above the third ferrite core section 7. This does not represent a limitation of the present invention and the first winding W1 can alternatively be arranged only over the first ferrite core section 3 or the third ferrite core section 7.

Furthermore, a second winding W2 is arranged over the second ferrite core section 5. The second winding W2 defines a second winding axis A3. According to the explanations for the first winding axis A1, the second winding axis A3 can be understood as a direction which is rotated by the individual turns of the second winding W2 and which is oriented parallel to a pitch between two successive turns of the second winding W2.

In illustrative embodiments of the invention, the first winding axis A1 and the second winding axis A3 are not oriented parallel to one another. For example, the first winding axis A1 and the second winding axis A3 can intersect at one point or be arranged skewed to one another. According to a specific illustrative example of how in Fig. 1 is shown, the first winding axis A1 and the second winding axis A3 are oriented perpendicular to each other.

In illustrative embodiments, the ferrite core on the second ferrite core section 5 has at least one small dimension relative to the first ferrite core section 3 and third ferrite core sections 7 in at least one direction. For example, the ferrite core on the second ferrite core portion 5 has a small dimension in a direction parallel to the first winding axis A1 relative to the first and third ferrite core portions 3, 7. In particular, the second ferrite core section 5 can at least partially have a dimension along a direction parallel to the first winding axis A1, which is smaller than a dimension of the first and / or third ferrite core section 3, 7 along a direction parallel to the first winding axis A1. In illustrative examples herein, a dimension of at least one tapered section of the second ferrite core section 5, normalized to a dimension of the first ferrite core section 3 or the third ferrite core section 7, can be less than 0.8, preferably less than 0.5, more preferably less than 0, 3. According to specific illustrative examples herein, a ratio of a dimension of the second ferrite core section 5 to a dimension of the first ferrite core section 3 and / or the third ferrite core section 7 along a direction parallel to the first winding axis A1 can be, for example, 0.2 or less, for example 0.1 or less be. In other words, in the contour of the ferrite core, the taper on the second ferrite core section 5 is formed in such a way that a dimension of the ferrite core in a direction parallel to the first winding axis is small relative to the first and third ferrite core sections 3, 7 Ferrite core section 5 are advantageously included in the contour. Furthermore, the magnetic flux density in the ferrite core is concentrated in a receiving mode.

The first and third ferrite core sections 3, 7 can be formed as individual elongated ferrite rods attached to the second ferrite core section 5, as in FIG Fig. 1 is shown. The ferrite core sections 3, 7 can be parallel or essentially parallel to one another. The second ferrite core section 5 can be arranged perpendicularly or substantially perpendicularly to each of the first and third ferrite core sections 3, 7. In addition, the second ferrite core section 5 is shown in FIG Fig. 1 formed as a cylindrical ferrite rod, which has a smaller dimension in accordance with the above explanations, as will be described in more detail below.

As shown in Fig. 1 the ferrite core has an H-shape in a view of the ferrite core along a direction perpendicular to the winding axes A1 and A3. As shown in Fig. 1 the second ferrite core section 5 of the ferrite rod antenna 1 has a dimension ("second length dimension") which is smaller than one dimension along a direction perpendicular to a parallel line of the first winding axis A1 (and thus perpendicular to the longitudinal direction of the first and third ferrite core sections 3, 7) of the ferrite core of the ferrite rod antenna 1 along this direction perpendicular to a direction parallel to the first winding axis A1 (in particular, a direction perpendicular to the longitudinal direction of the first and third ferrite core sections 3, 7 or "first length dimension"). In configurations of the second ferrite core section 5 in which the second ferrite core section 5 has smaller dimensions relative to the corresponding dimensions of the first and third ferrite core sections 3, 7, in particular along directions that are not parallel to the second winding axis A3, the second winding W2 is smaller Winding diameter provided, which results in a relatively low DC resistance for the winding W2. For example, the second length dimension can be a factor of “1.5” or at least a factor “2” or at least a factor “3” or at least a factor “5” smaller than the first length dimension

As shown in Fig. 1 For example, the ferrite core of the ferrite rod antenna 1 has an elongated shape which is defined by the shape of the first and third ferrite core sections 3, 7. A longitudinal direction can thus be assigned to the ferrite core of the ferrite rod antenna 1 corresponding to the longitudinal direction of the first and third ferrite core sections 3, 7, which according to the illustration in FIG Fig. 1 is oriented essentially parallel to the first winding axis A1 and essentially perpendicular to the second winding axis A3. In this case, a dimension of the second ferrite core section 5 at least along the longitudinal direction is smaller than a dimension of the first ferrite core section 3 along the longitudinal direction and / or a dimension of the third ferrite core section 7 along the longitudinal direction, so that the ferrite core of the ferrite rod antenna 1 tapers in the second ferrite core section 5 is.

According to the in Fig. 1 In the illustrated embodiment, the ferrite core of the ferrite rod antenna 1 is tapered along the second ferrite core section 5. This does not represent a limitation of the invention and only a section of the second ferrite core section 5 can be tapered. For example, a dimension of the second ferrite core section 5 to the first ferrite core section 3 and / or to the third ferrite core section 7 can be steadily matched to a dimension of the first ferrite core section 3 and / or to a dimension of the third ferrite core section 7, in particular there is no step between the second Ferrite core section 5 and at least one adjacent ferrite core section 3 and / or 7 formed.

As shown in Fig. 1 are the first ferrite core portion 3 and third ferrite core portion 7 along a connection direction that is substantially parallel to second winding axis A3 and is oriented essentially perpendicular to the longitudinal direction of the first and third ferrite core sections 3, 7, spaced apart from one another by the second ferrite core section 5. This means that a winding diameter of the first winding W1 by a dimension of the first and third ferrite core sections 3, 7 along a direction parallel to the second winding axis A3 and a dimension of the second ferrite core section 5 extending between the first ferrite core section 3 and the third ferrite core section 7 along the Connection direction, in particular parallel to the second winding axis A3, is determined. In contrast, a winding diameter of the second winding W2 is given only by a cross-sectional area of the second ferrite core section 5 perpendicular to the second winding axis A3. According to an illustrative example herein, a dimension of the second ferrite core portion 5 in a width direction perpendicular to the longitudinal direction and perpendicular to the connection direction may be less than or equal to a smallest dimension of dimensions of the first and third ferrite core portions 3, 7 in the width direction, as in FIG Fig. 1 is shown.

The first ferrite core section 3 and the third ferrite core section 7 are arranged on opposite end faces of the second ferrite core section 5 and the second winding W2 is arranged over part of a lateral surface of the second ferrite core section 5. This provides a configuration in which the second winding axis A3 is oriented essentially parallel to surface normals of the lateral surfaces of the first and third ferrite core sections 3, 7, while the first winding axis A1 is essentially parallel to surface normals of opposite end faces 9a, 9b of the third ferrite core section 7 or opposite end faces 8a, 8b of the first ferrite core section 3, which are arranged on opposite ends 4, 6 of the first and third ferrite core sections 3, 7 in the longitudinal direction. The outer surface of the first ferrite core section 3 is in Fig. 1 denoted by the reference number "11" for illustration. In particular, the "outer surface" of the first ferrite core section 3 is to be understood as the amount of surfaces of the first ferrite core section 3 that are not in mechanical contact with the second ferrite core section 5, are directed away from the latter and are not identical to the end faces 8a, 8b of the first ferrite core section 3 are. The term "jacket surface" is to be applied accordingly to the third ferrite core section 7. When “Jacket surfaces” of the second ferrite core section 5 are to be understood as the surfaces of the second ferrite core section 5 that are exposed in the ferrite core of the ferrite rod antenna 1.

The first winding W1 of the ferrite rod antenna 1 is arranged over a region of the lateral surface of the first and third ferrite core sections 3, 7. The outer surfaces of the first and third ferrite core sections 3, 7 form the outer surface of the ferrite rod antenna 1, via which magnetic field components of electromagnetic waves are received by the ferrite rod antenna 1 or are coupled into the ferrite core of the ferrite rod antenna 1, as indicated by arrows P1 in Fig. 1 is shown to illustrate magnetic field components. According to illustrative examples, the first winding W1 can cover the outer surface of the ferrite rod antenna 1 at the opposite ends 4, 6 of the ferrite rod antenna 1 or be arranged above it and in particular leave end faces 8a, 8b, 9a, 9b of the ferrite rod antenna 1 free, as well as a section of the outer surface of the The ferrite rod antenna 1 is essentially free between the opposite ends 4, 6 of the ferrite rod antenna 1. In this way, when the ferrite rod antenna 1 is operated as a transmitting antenna, the first winding W1 can be operated by suitably connecting terminals A0, A2 of the first winding W1 to a transmitting unit (not shown) for radiating magnetic field components according to arrows P2 or anti-parallel thereto. When the ferrite rod antenna 1 is operated as a receiving antenna, magnetic field components which hit the outer surface of the ferrite rod antenna 1 according to the arrows P1 can be concentrated in the second ferrite core section 5 and induce a voltage signal in the second winding W2, which is transmitted via connections A3, A4 of the second winding W2 can be tapped.

In the Fig. 1 The ferrite rod antenna shown here therefore provides a core geometry for the ferrite core, the ferrite core having a large surface area and at the same time the second winding W2 being able to be provided with a low direct current resistance. Furthermore, the ferrite core of the ferrite rod antenna 1 by means of the end faces 8a, 8b, 9a, 9b of the first and third ferrite core sections 3, 7 provides the possibility of a directed radiation of a magnetic field according to the arrows P2 or anti-parallel to the arrows P2 in operation as a transmitting antenna , in which the connections A0, A2 of the first winding W1 are suitably connected to a transmitter unit (not shown).

In illustrative embodiments, edges of the first and third ferrite core sections 3, 7 in the outer surface of the ferrite core can be rounded and thus serve as bearing surfaces against which winding sections of individual turns of the first winding W1 are applied. This allows the in Fig. 1 The ferrite core shown can be wound in a simple manner without the risk of damaging the winding W1.

Regarding Figure 3 various embodiments for a ferrite core of the ferrite rod antenna 1 are described with reference to FIG Fig. 1 is described above.

Figure 3 FIG. 11 schematically shows, in a disassembled perspective view, a ferrite core portion 41 corresponding to the first ferrite core portion 3 Figure 1 or the third ferrite core portion 7 Figure 1 In a side face of the ferrite core section 41, a recess 45 is formed which at least partially penetrates the ferrite core section 41. The recess 45 is formed or dimensioned in such a way that a ferrite core section 43 corresponds to the second ferrite core section 5 Figure 1 can be partially inserted into the recess 45. In particular, a shape of the recess 45 is coordinated with a shape of the second ferrite core section 43 such that the second ferrite core section 43 can be received in the recess 45 (possibly with additional adhesives).

According to alternative embodiments of the ferrite rod antenna 1, the first to third ferrite core sections 3, 5, 7 shown in FIG Figure 1 are shown, deviating from the description Figure 3 be designed as sections of an integrally formed ferrite core, for example the second ferrite core section 5 in Figure 1 be formed by cutting a cuboid ferrite core blank. Alternatively, the ferrite core of the ferrite rod antenna 1 can be formed by pressing the ferrite core in the manner shown in FIG Figure 1 or the ferrite core can be formed by gluing the ferrite core sections 3, 5, 7 to one another, the individual ferrite core sections 3, 5, 7 being glued to one another on flat surface sections so that the correspondingly formed ferrite core has an H-shaped shape as referring to Fig. 1 is described.

Regarding Figure 2 further illustrative embodiments of the invention are described.

Figure 2 shows a ferrite rod antenna 20 with a ferrite core comprising a first ferrite core portion 21, a second ferrite core portion 29 and a third ferrite core portion 23, the second ferrite core portion 29 spacing the first ferrite core portion 21 and the third ferrite core portion 23 from one another. Furthermore, the ferrite core of the ferrite rod antenna 20 has a fourth ferrite core section 27 and a fifth ferrite core section 25, which are connected both to one another and to the first and third ferrite core portions 21, 23 are spaced apart by the second ferrite core portion 29.

According to illustrative but non-limiting examples, the second ferrite core section 29 is cube-shaped or cuboid, and the first ferrite core section 21, the third ferrite core section 23, the fourth ferrite core section 27 and the fifth ferrite core section 25 are arranged along mutually parallel edges of the second ferrite core section 29. As shown in Fig. 2 the ferrite core sections 21, 23, 25 and 27 are designed as ferrite rods. These can be similar to the Fig. 1 described ferrite core sections 3, 7 be formed. The representation in Fig. 2 is for illustrative purposes only and is not necessarily to be understood as being to scale. Dimensions can be enlarged / reduced to accommodate individual features in the representation of the Fig. 2 to be able to represent it more clearly. For example, the ferrite rods 21, 23, 25, 27 can be compared to the illustration in FIG Fig. 2 be less filigree to stabilize the core.

According to illustrative embodiments of the ferrite rod antenna 20, the first ferrite core section 21 is spaced apart from the fourth ferrite core section 27 by a first distance Sp1 and spaced apart from the third ferrite core section 23 by a second distance Sp2. The fifth ferrite core section 25 is arranged from the third ferrite core section 23 under a third section Sp3 and arranged relative to the fourth ferrite core section 27 under a fourth section Sp4. Due to the geometry of the second ferrite core section 29 and the arrangement of the ferrite core sections 21, 23, 25 and 27 on the second ferrite core section 29, for example, the second distance Sp2 and the fourth distance Sp4 are the same, while the first distance Sp1 and the third distance Sp3 are the same can. However, this is not a limitation of the present invention. By suitably arranging the ferrite core sections 21, 23, 25 and 27 on the second ferrite core section 29, the same distances Sp1 = Sp2 = Sp3 = Sp4 can also be set regardless of the geometry of the second ferrite core section 29 . Alternatively, at least one of the distances Sp1 to Sp4 can also differ from at least one other of the distances Sp1 to Sp4.

With regard to a geometry of the ferrite core sections 21, 23, 25, 27, 29 and a geometry of windings which are arranged over the ferrite core sections 21, 23, 25, 27, 29, as described below, reference is made to the in Figure 2 Reference is made to the coordinate system shown, in which three axes x, y, z are arranged in pairs perpendicular to one another. A direction along the x-axis is referred to as a longitudinal direction and a dimension along the longitudinal direction is referred to as a longitudinal dimension. Regarding the ferrite core portions 21, 23, 25, 27 and 29 represent directions along the y-axis and / or the z-axis Connection directions which are oriented perpendicular to the longitudinal direction and along which the ferrite core sections 21, 23, 25, 27 are spaced apart from one another by the second ferrite core section 29. In particular, the distances Sp1, Sp2, Sp3 and Sp4 are each measured along one of the y-axis and the z-axis perpendicular to the longitudinal direction (the x-axis).

According to illustrative embodiments, the longitudinal dimensions of the ferrite core sections 21, 23, 25 and 27 are greater than a longitudinal dimension of the second ferrite core section 29. For example, the longitudinal dimension of the second ferrite core section 29 is at most 80% of a largest longitudinal dimension from the longitudinal dimensions of the ferrite core sections 21, 23, 25 and 27 or the longitudinal dimension of the ferrite core sections 21, 23, 25 and 27, if the ferrite core sections 21, 23, 25 and 27 (apart from tolerances) are of the same longitudinal dimension.

According to illustrative examples herein, the longitudinal dimension of the second ferrite core section 29 is at most 70% or at most 50% or at most 30% of a maximum longitudinal dimension of the longitudinal dimensions of the ferrite core sections 21, 23, 25 and 27 or the longitudinal dimension of the ferrite core sections 21, 23, 25 and 27, if the ferrite core sections 21, 23, 25 and 27 (apart from tolerances) are of the same longitudinal dimension.

According to illustrative embodiments, each of the ferrite core portions 21, 23, 25 and 27 has an elongated shape; That is, the longitudinal dimensions of the ferrite core portions 21, 23, 25 and 27 are larger than dimensions of the ferrite core portions 21, 23, 25 and 27 along the y-axis and the z-axis. For example, a ratio of the longitudinal dimension of the ferrite core sections 21, 23, 25 and 27 to dimensions of the ferrite core sections 21, 23, 25 and 27 along the x-axis and along the z-axis can be at least two or at least five or at least ten.

As shown in Figure 2 For example, the second ferrite core section 29 can be formed in a cube-shaped or cuboid shape. The first ferrite core portion 21 and the fourth ferrite core portion 27 are in contact with one side surface of the second ferrite core portion 25, while the third ferrite core portion 23 and the fifth ferrite core portion 25 are in contact with an opposite side surface of the second ferrite core portion 25. This is not a limitation of the present invention, and the ferrite core portion 21 together with the ferrite core portion 23 can contact a side surface of the second ferrite core portion 29, while the ferrite core portions 25 and 27 can contact an opposite second surface of the second ferrite core portion 29. Alternatively, the ferrite core sections 21, 23, 25 and 27 contact different side surfaces of the second ferrite core section 29, the surface normals of which are each parallel or antiparallel to a connection direction (y-axis or z-axis in Figure 2 ) are.

Each of the ferrite core sections 21, 23, 25 and 27 has a side surface which is in contact with the second ferrite core section 29, and end surfaces 31 whose surface normals are parallel to the longitudinal direction (x-axis in Figure 2 ) are oriented. End faces opposite to end faces 31 are shown in FIG Figure 2 not designated and should be regarded as falling under the term "end faces 31". Furthermore, each of the ferrite core sections 21, 23, 25 and 27 has, in addition to the end faces, a respective lateral surface 33, which represents an outwardly exposed surface of each ferrite core section 21, 23, 25 and 27.

The ferrite rod antenna 20 further comprises a first winding W10, which is arranged above the ferrite core sections 21, 23, 25 and 27 and a first winding axis is oriented in the direction of the x-axis. In the coordinate system in Figure 2 the first winding W10 is shown for the sake of clarity, which shows a spatial orientation of the first winding W10 with respect to the x-axis. In the following, the x-axis is therefore assigned to the first winding W10 as the “first winding axis”.

In illustrative embodiments, the first winding W10 is arranged above the ferrite core sections 21, 23, 25 and 27, so that the jacket surfaces 33 of the ferrite core sections 21, 23, 25 and 27 act as contact surfaces for individual turns of the first winding W10 at end areas EA and EB of the ferrite core sections 21, 23, 25 and 27 are arranged. The end areas EA and EB of the ferrite core sections 21, 23, 25 and 27 are to be understood as areas of the ferrite core sections 21, 23, 25 and 27 which are arranged at opposite ends of the ferrite core sections 21, 23, 25 and 27 on which the ferrite core sections 21 , 23, 25 and 27 are not in contact with the second ferrite core portion 29. The end regions EA and EB thus represent regions of the ferrite core sections 21, 23, 25 and 27 which extend along the longitudinal direction (x-axis in FIG Figure 2 ) extend over the second ferrite core section 29. A connection area is arranged between the end areas EA and EB, which denotes areas of the ferrite core sections 21, 23, 25 and 27, along which the ferrite core sections 21, 23, 25 and 27 with the second ferrite core section 29 along the longitudinal direction (x-axis in Figure 2 ) are in mechanical contact. In particular, the first winding W10 is divided into winding sections W1a, W1b and W1c according to the end regions EA, EB and the connection region. The winding sections W1a and W1b are arranged over the end regions EA and EB of the ferrite core sections 21, 23, 25 and 27 and represent turns of the first winding W10 that circulate around the ferrite core sections 21, 23, 25 and 27. The winding section W1c of the first winding W10 runs along the connection area M essentially parallel to the longitudinal direction (x-axis in Figure 2 ), where "essentially" means that the winding section W1c does not completely circulate the ferrite core sections 21, 23, 25 and 27 along the connecting area M, in particular a number of rotations assigned to the winding section W1c with regard to the ferrite core sections 21, 23, 25 and 27 measured in Radians are less than 2π. The winding section W1c is only in contact with the ferrite core section 27 along the connection area M or is guided along the ferrite core section 27.

The preceding description of the first winding W10 does not represent a restriction of the present invention and the winding W10 can only be arranged over a region of the ferrite core sections 21, 23, 25 and 27, for example only over the region EA or only over the region M or only over the area EB or only over the areas EA and M or only over the areas EB and M. Connections of the first winding W10 are in Figure 2 denoted by the reference characters A11 and A12.

A second winding W12 and a third winding W14 are also arranged above the second ferrite core section 29. The windings W12 and W14 are oriented orthogonally to one another, as in the coordinate system in FIG Figure 2 is drawn for illustration. The second winding W12 is assigned a second winding axis which is identified with the z-axis. The third winding W14 is assigned a third winding axis which is identified with the y-axis. In Figure 2 connections of the second winding W12 are labeled A21 and A22. Connections of the third winding W14 are in Figure 2 labeled A41 and A42.

As shown in Figure 2 the first to third winding axes are perpendicular to each other in pairs.

The ferrite rod antenna 20 can function as a transmitting antenna in a transmitting mode, the first winding W10 being connected to a transmitting unit (not shown) via connections A11 and A12 and emitting a magnetic field via the end faces 31. In a receiving mode of the ferrite rod antenna 20, the second winding W12 via connections A21 and A22 and / or the third winding W14 via connections A41 and A42 are connected to a receiving unit (not shown) in order to receive a signal via the lateral surfaces 33.

According to some illustrative embodiments of the invention, the longitudinal winding W10 between A11 and A12, contrary to the illustration in FIG Fig. 2 in the entire x-direction along the ferrite core sections 21, 23, 25, 27 away. In this case, the winding is continued in the winding section W1c.

Regarding Figure 4 A transmitting and receiving unit 100 will now be described. The transmitting and receiving unit 100 can comprise a ferrite rod antenna as above with regard to the ferrite rod antenna 1 in FIG Figure 1 and the ferrite rod antenna 20 in Figure 2 is described. One winding 101 corresponds to the above-described first winding W1 or W10, and one winding 103 corresponds to the above-described second winding W2 or W12. In the case of the ferrite rod antenna 20 described above, a third winding 105 is also provided, which corresponds to the third winding W14 described above. The winding 105 is optional, which is shown in Figure 4 indicated by the brackets.

In a receive mode, the winding 103 and / or 105 is connected to an electronic receiver circuit 112. In a transmission mode, the winding 101 is electrically connected to a transmission unit 114. The transmitting unit 114 and receiving unit 112 can be connected to a digital signal processor module 110, which can furthermore be connected to an audio signal output unit (not shown) for outputting audio signals and an audio signal input unit for receiving audio signals. For example, the transmission unit 114 can comprise a transmission oscillator circuit which can be connected to the winding 101 by means of a switch 116 and which can be connected to the digital signal processor module 110. The digital signal processor module 110 can transmit signals to the transmission unit 114 which represent audio signals converted into electrical signals by the digital signal processor module 110. The digital signal processor module 110 exchange signals with the transmission unit 114 in order to output audio signals via an audio output device (not shown), such as a loudspeaker, headphones, etc., for example.

The ferrite rod antenna (see 1 in Fig. 1 ; see 20 in Fig. 2 ) connected in series with a capacitor (not shown). At the operating frequency of the ferrite rod antenna (see 1 in Fig. 1 ; see 20 in Fig. 2 ) and the capacitor (not shown), the reactances compensate each other and the resonant circuit becomes low-resistance, as a result of which a maximum current flows through the winding 101. As a result, the winding 101 in the ferrite rod antenna (cf. 1 in Fig. 1 ; see 20 in Fig. 2 ) a corresponding flux density B, which over the end faces of the ferrite rod antenna (see. 1 in Fig. 1 ; see 20 in Fig. 2 ) is decoupled as described above.

In receive mode, the ferrite rod antenna (see 1 in Fig. 1 ; see 20 in Fig. 2 ) connected in parallel to a capacitor (not shown). As a result, the resonant circuit consisting of winding 103 and / or 105 and capacitor (not shown) has a high resistance and an induced voltage is applied to winding 103 and / or winding 105.

Regarding Fig. 2 a ferrite rod antenna 20 is also disclosed which comprises a ferrite core formed by five interconnected ferrite rods 21, 23, 25, 27, 29, and a first winding W10 and a second winding W14, each arranged above the ferrite core, wherein four ferrite rods 21, 23, 25, 27 of the ferrite core have a first length dimension and the other ferrite rod 29 of the ferrite core has a second length dimension which is smaller than the first length dimension. The ferrite rod 29 with the second length dimension is arranged perpendicular or essentially perpendicular to the four ferrite rods 21, 23, 25, 27 with the first length dimension, so that they are spaced from one another by the ferrite rod 29 with the second length dimension. Furthermore, the first winding W10 is arranged over the ferrite rods 21, 23, 25, 27 with the first length dimension, while the second winding W14 is arranged over the ferrite rod 29 with the second length dimension. In addition, as in Fig. 2 is shown, a third winding W12 can be arranged above the ferrite rod 29 with the second length dimension, the winding axes of the windings W10, W12, W14 being oriented in pairs perpendicular or substantially perpendicular to one another.

Furthermore, the four ferrite rods 21, 23, 25, 27 with the first length dimension can be arranged in pairs parallel to one another or essentially parallel on the ferrite rod 29 with the second length dimension. For example, the ferrite rod 29 can have a block-like or cuboid shape (in a specific example a cube-shaped shape) opposite the four ferrite rods 21, 23, 25, 27, the four ferrite rods 21, 23, 25, 27 running along parallel edges of this block-like shape or cuboid ferrite rod 29 can extend, as in Fig. 2 is illustrated. The four ferrite rods 21, 23, 25, 27 are each spaced apart from one another by the block-like or cuboid ferrite rod 29.

As shown in Fig. 2 shows the ferrite core in a planar side view along one of the directions x, y and z in Fig. 2 an H-shaped shape.

Claims (7)

1. A ferrite-rod antenna (1) comprising a ferrite core having a first ferrite core portion (3), a second ferrite core portion (5) and a third ferrite core portion (7), said first ferrite core portion (3) and said third ferrite core portion (7) being spaced apart from each other by said second ferrite core portion (5), and a first winding (W1) disposed above said first ferrite core portion (3) and/or said third ferrite core portion (7) and defining a first winding axis (A1), and a second winding (W2) disposed above said second ferrite core portion (5) and defining a second winding axis (A3) which is not parallel to said first winding axis (A1),
   wherein the ferrite core at the second ferrite core portion (5) is at least partially tapered relative to the first and third ferrite core portions (3, 7) in at least one direction, wherein the ferrite core (1) at the second ferrite core portion (5) has a small dimension in a direction parallel to the first winding axis (A1) relative to the first and third ferrite core portions (3, 7),
   wherein the ferrite core has an elongated shape defining a longitudinal direction, and a dimension of the second ferrite core portion (5) along the longitudinal direction is smaller than a dimension of the first ferrite core portion (3) along the longitudinal direction and/or a dimension of the third ferrite core portion (7) along the longitudinal direction,
   wherein the first and third ferrite core portions (3, 7) are spaced apart from each other by the second ferrite core portion (5) along a connecting direction perpendicular to the longitudinal direction of the first and third ferrite core portions (3, 7),
   wherein a dimension of the second ferrite core portion (5) in a width direction perpendicular to the longitudinal direction and perpendicular to the connecting direction is smaller than or equal to a smallest dimension among dimensions of the first and third ferrite core portions (3, 7) in their respective width directions, and
   wherein said second ferrite core portion (5) has a cylindrical shape, said first and third ferrite core portions (3, 7) are disposed on opposite end faces of said second ferrite core portion (5), and said second winding (W2) is disposed over a part of a circumferential surface of said second ferrite core portion.
2. The ferrite-rod antenna (1) according to claim 1, wherein the first winding axis (A1) is aligned parallel to the longitudinal direction.
3. The ferrite-rod antenna (1) according to claim 1 or 2, wherein the first winding (W1) is arranged over regions of a circumferential surface of the ferrite rod antenna (1) at opposite ends (4, 6) of the ferrite rod antenna (1) at the first and third ferrite core portions, wherein in particular end faces (8a, 8b, 9a, 9b) of the ferrite rod antenna (1) and the second ferrite core portion (5) are exposed with respect to the first winding (W1).
4. The ferrite-rod antenna (1) according to any one of claims 1 to 3, wherein the first ferrite core portion (3) and the third ferrite core portion (7) have at least one rounded edge as a supporting surface for the first winding.
5. The ferrite-rod antenna (1) according to any one of claims 1 to 4, wherein the first ferrite core portion (3) and the third ferrite core portion (7, 41) each have a recess (45) in which the second ferrite core portion (5, 43) is partially received.
6. A ferrite rod antenna (20) comprising a ferrite core formed by at least five interconnected ferrite rods (21, 23, 25, 27, 29) and a first winding (W10) and a second winding (W14) each disposed over the ferrite core, wherein four ferrite rods (21, 23, 25, 27, 29) of the at least five ferrite rods (21, 23, 25, 27, 29) have a first length dimension and the other ferrite rod (29) of the at least five ferrite rods (21, 23, 25, 27, 29) has a second length dimension smaller than said first length dimension, wherein said four ferrite rods (21, 23, 25, 27) having the first length dimension each being arranged parallel to each other at the ferrite rod (29) having the second length dimension and each being spaced apart from each other by the ferrite rod (29) having the second length dimension, the ferrite rod (29) having the second length dimension being perpendicular or substantially perpendicular to the four ferrite rods (21, 23, 25, 27) having the first length dimension, and the first winding (W10) is disposed above the four ferrite rods (21, 23, 25, 27) having the first length dimension, while the second winding (W14) is disposed above the ferrite rod (29) having the second length dimension, wherein the ferrite core has an H-shaped configuration in a side view of the five ferrite rods (21, 23, 25, 27, 29).
7. A transmitter and receiver unit (100) comprising the ferrite rod antenna (1; 20) according to any one of claims 1 to 6, further comprising an electronic transmitter circuit (114) electrically connected to the first winding (W1; W10) and an electronic receiver circuit (112) electrically connected to at least the second winding (W2; W12).

Images