EP3513457B1 - Antenna device and method for emitting electromagnetic waves using the antenna device - Google Patents

Description

The invention relates to an antenna device for radiating electromagnetic waves with a waveguide which has two plates of electrically conductive material arranged parallel to one another, between which a dielectric material is arranged, and with a feed device with which electromagnetic waves can be coupled into the waveguide, which then propagate along the waveguide and are emitted at an edge of the waveguide which is spaced apart from the feed device.

A large number of different antennas with which electromagnetic waves can be emitted or received are known from practice. US4809011 A , US5450092 A , US 9366938 B1 , US 2004/160382 , US 2010/060521 disclose some examples of such antennas. The different antenna devices are adapted to different wavelength ranges of the electromagnetic radiation and to the respective requirements with regard to the desired radiation power, the radiation characteristics and the respective intended areas of use. For example, a distinction can be made between linear antennas, which have a linear current distribution in the antenna structure, and surface antennas, in which a line-guided wave is emitted over a, for example, strip-shaped or circular surface.

In order to reduce transmission losses of the electromagnetic waves from a transmitter to a receiver, it is advantageous to focus the electromagnetic radiation emitted by the transmitter in the direction of the receiver, so that the largest possible proportion of the radiation power emitted by the transmitter is emitted in the direction of the receiver and can be received from this. For this purpose, various antenna devices are known from practice in which the radiation characteristics of the antenna device are influenced and the direction of the maximum radiation power or the preferred radiation direction can be changed and aligned with a receiver arranged at a distance from the antenna device.

In particular at low frequencies or long wavelengths, antenna devices with mechanically displaceable components are used, the displacement of which enables the radiation characteristics to be changed and the direction-dependent transmission power to be influenced.

Antenna arrays are also known in which a number of antenna devices that are spaced apart from one another emit electromagnetic waves that are coordinated with one another so that the resulting superimposition of the electromagnetic waves emitted by the individual antenna devices results in a preferred direction in which the greatest radiation power is emitted.

For high-frequency electromagnetic waves with a frequency of gigahertz or terrahertz, for example, the characteristic dimensions of the antenna devices are locally in the range of millimeters and smaller in order to at least approximately correspond to the wavelength of the emitted or received electromagnetic radiation. The manufacture of antenna devices with components which can be mechanically displaced relative to one another and which would be suitable for the emission of such high-frequency electromagnetic waves is very complex and cost-intensive. In contrast, the operation of antenna arrays, in which electromagnetic waves with a frequency of gigahertz and higher can be emitted with each individual antenna device, are relatively high due to the necessary division of the antenna signal over a large number of individual antenna devices and due to the losses in the respective phase shifters Loss of transmission power.

Antenna devices of the type mentioned at the beginning, in which the electromagnetic wave propagates along a waveguide formed from two plates arranged parallel to one another and is radiated from one edge of the waveguide, are also suitable, as experience has shown, for the radiation of high-frequency electromagnetic waves with a frequency of one gigahertz and more. However, no antenna devices of this type are known which would allow the radiation characteristics of the emitted electromagnetic waves to be influenced.

It is therefore seen as an object of the present invention to design and further develop an antenna device of the type mentioned at the beginning so that the radiation characteristics and in particular the direction of a maximum radiation power of the antenna device can be influenced and specified with simple means and with the lowest possible losses.

According to the invention, this object is achieved in that the dielectric material can be influenced with a control device of the antenna device in such a way that at least one first region with a first permittivity and at least one second region with a second permittivity is formed, so that the electromagnetic waves coupled into the waveguide propagate almost exclusively through the at least one first region with higher permittivity and are emitted in this preferred direction of propagation. It is not necessary to change the alignment of the two plates arranged parallel to one another. It has been shown that the formation of a first area between the two parallel plates, the first permittivity of which differs from at least one adjacent second area, is sufficient to influence and specify the preferred direction of propagation of the electromagnetic waves coupled in via the feed device . The greater the difference between the first permittivity and the second permittivity and the more clearly the first area is delimited from a second adjacent area, the more pronounced the preferred direction of propagation can be influenced and specified. Depending on the material used in each case, the permittivity of the dielectric material can also be carried out without contact or without mechanical displacement of individual components of the antenna device. Depending on the dielectric material used in each case and the mode of operation of the control device, very short response times can be made possible when the preferred direction of propagation is adapted.

The shape of the plates arranged parallel to one another and in particular the arrangement of the feed device and the course of the edge of the waveguide spaced from the feed device can be specified depending on the intended use of the antenna device and, for example, on a desired frequency range of the electromagnetic waves and the desired variation possibilities for the Orientation be adapted to the preferred direction of propagation.

According to a particularly advantageous embodiment of the inventive concept, it is provided that the waveguide is shaped like a segment of a circle and the feed device feeds the electromagnetic wave in the center of the circle, and that the at least one first area and the at least one second area each start from the center of the circle within smaller circle segments of the waveguide. With such a configuration of the antenna device, the preferred direction of propagation of the electromagnetic waves can be varied over the entire angular range of the waveguide designed as a segment of a circle is covered. The first area, which specifies the preferred direction of propagation, can be formed by a small segment of a circle that can be aligned in different directions within the waveguide. If the first area is not directly adjacent to an edge area of the waveguide, the first area with a higher permittivity is expediently bounded on both sides by a second area with a lower permittivity, with every second area also being designed as a smaller circle segment and the individual circle segments of the The first area and the two second areas completely cover the segment of a circle or the angular area of the waveguide.

The waveguide can, for example, be semicircular and extend over an angular range of 180 °. The at least one first region, which, with its higher permittivity, specifies the preferred propagation device, can be, for example, a segment of a circle adapted to the waveguide with an opening angle of approximately 10 ° to 20 °. The two second areas each adjoin the assigned first area in the circumferential direction and cover the angular area of the waveguide that is not covered by the first area and thus, in the example mentioned, an angular area totaling 170 ° or 160 °.

It is also possible to specify the waveguide with an angular range smaller than 180 °, provided that the preferred direction of propagation should only be able to be changed within a smaller angular range. It is of course also possible to use the two To design the waveguide as circular plates and to arrange and design the feed device in the center of the circle in such a way that the electromagnetic waves are coupled in from the outside in the area of the center of the circle and fed in between the two circular plates and can then spread over the entire angular range of 360 °. The configuration and alignment of the at least one first area can then be used to specify a preferred direction of propagation within the complete circular angle of 360 °.

The at least one first area and the at least one second area can extend in the radial direction from the center of the circle to the edge area. It is also possible that the first area does not extend in the radial direction up to the edge area of the waveguide, but only over a partial area. The radius of the first area can be more than 50%, preferably more than 75% of the radius of the edge area.

If the preferred direction of propagation should only be able to be changed or switched between two or three or more individual directions, it is advantageous, according to one embodiment of the inventive concept, that the waveguide has an outer peripheral edge running along several adjoining circular chords and that the feed device feeds the electromagnetic wave feeds the center of the circle, and that edges of the at least one first region and of the at least one starting from the center of the circle second area each run through the intersection of the chord of the circle assigned to the first and second area with a circumferential circle. The circumferential circle delimiting the at least one first area and the at least one second area in the radial direction can correspond to the outer circumferential edge of the waveguide, but can also have a smaller radius. The individual circular chord sections then each run perpendicular to the preferred direction of propagation of the emitted electromagnetic waves, which is predetermined in this angular range around the feed device. The first region assigned to a circular chord, within which the electromagnetic waves should preferably propagate, is essentially triangular. Influencing the dielectric material in the individual angular areas delimited by circular chords can be implemented in a structurally simple and cost-effective manner.

According to an optional variant, the invention provides that the control device of the antenna device can influence the dielectric material in such a way that two first regions with a first permittivity and at least one intermediate second region with a second permittivity are formed. The two first areas are preferably delimited in the circumferential direction on both sides by a second area. With the first two areas it can be achieved that the antenna device simultaneously emits electromagnetic waves in two different preferred directions of propagation. There are two main radiation directions in which the predominant Part of the coupled electromagnetic waves or the coupled electromagnetic radiation power is emitted.

One embodiment of the inventive concept provides that the dielectric material is a dielectric solid, the shape of which corresponds to the first region and the orientation of which can be changed relative to the feed device. The dielectric solid can, for example, be a segment of a circle or a triangle made of a dielectric material with a high permittivity in the intended wavelength range of the emitted electromagnetic waves. A suitable dielectric material for many applications is, for example, a polystyrene plastic with a permittivity of ε _r = 2.53 at 50 GHz. The dielectric solid can, for example, be displaced by the control device of the antenna device by a suitable forced guidance and in each case aligned in the preferred direction of propagation. It is also possible, for example by embedding magnetic materials, to predetermine the alignment of the dielectric material via externally applied variable magnetic fields. With sufficiently large antenna devices, a mechanical operative connection of the control device with the dielectric solid body can be provided and the dielectric solid body can be displaced, for example, by means of cables or guide rods, or via a gear mechanism.

The dielectric material can also be a controllable dielectric solid such as barium strontium titanate.

According to a preferred embodiment of the inventive concept it is provided that the dielectric material is a fluid with an anisotropic permittivity. A fluid suitable for this purpose is, for example, a liquid crystal material in which the individual rod-shaped molecules have permittivities that differ significantly from one another along a longitudinal axis and across it. The liquid crystal material can be influenced, for example, by applying an electric field, so that different permittivities can be specified for individual areas of the liquid crystal material in the direction of propagation of the electromagnetic waves through the waveguide. Due to the frequent use of such materials in other product areas, suitable liquid crystal materials are commercially available and inexpensively in various configurations.

The control of the liquid crystal material or the influencing of the alignment of individual liquid crystal molecules with the aid of externally generated electrical fields has already been well investigated and many variants and configurations are known from practice. For example, an electrode structure can be arranged on the plates in an electrically insulated manner and the control device can apply the desired voltage distribution to it in the space between the two plates To influence the liquid crystal material located with regard to the alignment of the individual liquid crystal molecules and thereby to specify the permittivity in the direction of propagation of the electromagnetic waves. A liquid crystal material is expediently used here, which has a particularly large anisotropy of permittivity.

According to the invention, the control device has a plurality of electrodes arranged on the plates of the waveguide and insulated from them or separately controllable electrode segments, between which an electric field can be generated, whereby the permittivity of the fluid arranged between the plates can be influenced and a first region with a first permittivity and at least one second area with a second permittivity can be specified. The greater the number of electrodes or the individually controllable segments of the electrodes on the plates, the more diverse are the possibilities of influencing and specifying the preferred direction of propagation of the emitted electromagnetic wave.

According to an advantageous embodiment of the inventive concept, it is provided that each electrode is designed in the form of a strip or a narrow segment of a circle and extends, starting from the feed device, to a spaced edge of the associated plate of the waveguide. With a sufficient number of electrodes configured in this way, individual angular regions of the waveguide can be subjected to an electric field in order to the dielectric fluid located in the plates to form a first region with a high permittivity and on at least one side, or optionally on both sides, adjoining second regions with a lower permittivity.

The electrodes do not necessarily have to be arranged directly on the plates. It is also conceivable that an electric field penetrating the waveguide is generated from the outside. It is furthermore also possible for the electric field to be generated by electrodes which are arranged between edge regions of the waveguide that run at a distance from one another between the plates or outside the plates of the waveguide.

It has been found that, according to an optional embodiment, it is particularly advantageous that the electrodes have a regularly or irregularly curved course along their edges and / or a regular or irregular three-dimensionally structured surface. The edges of the electrodes can, for example, have a wave-shaped or a crenellated course. The individual waves or battlements can be formed regularly or irregularly or follow one another. In particular, the surfaces of the electrodes facing the plates can have a three-dimensionally structured surface which has structures that are either regularly or irregularly arranged or formed. The non-straight course of the edges and the not completely planar design of the surfaces of the electrodes result in an undesirable influence on the Reduced electromagnetic fields for the wave radiation, which could possibly be generated by the formation of an electromagnetic field between the electrodes, which is required and generated for the formation of the first area between the electrodes with a first permittivity.

Furthermore, it is also possible to influence the dielectric material by means of an externally applied magnetic field which penetrates the waveguide. Depending on the properties of the dielectric material used, other mechanisms of action can also be used in order to bring about a predefined alignment of individual molecules and a change in permittivity, for example by appropriately specifying a pressure or a temperature.

In order to be able to adapt an adaptation of the wave resistance when the electromagnetic waves are detached from the waveguide into the free space and to reduce unwanted reflections at the edge of the waveguide, the invention provides that the two plates have an edge region spaced from the feed device as the distance from the feed device increases, the distance from one another increases. For this purpose, the edge regions of the two plates can either be angled obliquely outwards or they can taper to a point outwards. The edge region of the waveguide formed in this way acts like a horn antenna and enables an additional improvement in the radiation output in the preferred direction of propagation.

The edge areas of the two plates can also be arranged at a predetermined angle relative to the waveguide plane of the parallel areas of the waveguide so that the electromagnetic waves are emitted at an angle relative to the waveguide plane. Such a configuration of the edge regions can be advantageous when the antenna device is arranged as intended at an interface such as, for example, on a wall or on a ceiling.

It is also possible, and in particular with sufficiently large dimensions of the waveguide, can be implemented without great structural effort, that the edge areas of the two plates of the waveguide can be changed with regard to their alignment and / or shape during operation in order to influence the preferred direction of propagation through the edge areas and to be able to be changed in a directional plane which is perpendicular to the directional plane predetermined by the parallel plates, in which the preferred direction of propagation can be influenced and predetermined by the dielectric material.

The invention also relates to a method for radiating electromagnetic waves with an antenna device having the features described above. According to the invention it is provided that at least one first area with a first permittivity and at least one second area with a second permittivity are generated with the control device of the antenna device, so that the into the waveguide The coupled-in electromagnetic waves preferably propagate through the at least one first region and are emitted in this preferred direction of propagation.

It is possible according to the invention for the at least one first area to be designed as a segment of a circle or a triangle during operation of the antenna device and for the alignment of the segment or triangle to be adapted relative to the feed device as a function of a predetermined radiation direction. It is also possible for the first area to be designed like a circle segment or a triangle and for the angular area covered by the circle segment or triangle to be adapted as a function of a predetermined directional focus. For example, depending on the intended use in the desired direction of propagation, a comparatively broad radiation of the electromagnetic waves extending over a larger angular range can be specified by a broad first range, or a radiation of the electromagnetic waves focused on a very narrow angular range by the Specification of a correspondingly narrow first area can be specified. However, it has been shown that if the first area is predefined too narrow, the directional focusing deteriorates again, so that an advantageous width of the first area can be determined and predefined depending on the wavelength of the electromagnetic radiation and the configuration of the waveguide and the dielectric material , with the one the best possible directional focusing of the preferred radiation direction can be achieved.

It is also possible that both the broad or the angular area coverage of the first area and its alignment are changed simultaneously during the operation of the antenna device according to the invention.

According to the invention, the antenna device can also have several waveguides stacked one on top of the other, into which electromagnetic waves can be injected via a common feed device or via several separate feed devices each assigned to a waveguide. By means of a suitable combination of several waveguides, the overall electromagnetic radiation power emitted by the antenna device in a preferred radiation direction can be increased considerably.

It is of course also possible to arrange several antenna devices according to the invention at a distance from one another and to operate them in a synchronized manner in order to increase the overall electromagnetic radiation power emitted in the preferred direction of propagation. The plurality of antenna devices can be arranged spaced apart from one another in the form of a matrix or, for example, stacked one above the other. In the case of several antenna devices stacked one on top of the other, only the outer plates of the stacked waveguides can have an edge region, which form a single horn antenna for all waveguides.

In each antenna device, according to an optional embodiment of the inventive concept, two or more first areas can be formed at the same time and aligned such that the electromagnetic waves fed in propagate simultaneously in two or more preferred propagation directions.

• Figur 1 eine Seitenansicht einer erfindungsgemäßen Antenneneinrichtung,
• Figur 2 eine Schnittansicht durch die in Figur 1 gezeigte Antenneneinrichtung längs der Linie II-II in Fig. 1,
• Figur 3 eine schematische Darstellung der Ausbreitung von elektromagnetischen Wellen, die über die Einspeiseeinrichtung in einen Wellenleiter der Antenneneinrichtung eingekoppelt werden und sich längs eines ersten Bereichs mit einer ersten Permittivität in dem Wellenleiter ausbreiten,
• Figur 4 eine grafische Darstellung von Strahlungscharakteristiken von abgestrahlten elektromagnetischen Wellen, die mit einem Prototyp der in der Figuren 1 und 2 gezeigten erfindungsgemäßen Antenneneinrichtung erzeugt, in verschiedenen bevorzugten Ausbreitungsrichtungen abgestrahlt und vermessen wurden,
• Figur 5 eine schematische Draufsicht auf eine erfindungsgemäße Antenneneinrichtung mit einer an einer Platte des Wellenleiters angebrachten Elektrodenanordnung zur Beeinflussung eines zwischen den beiden Platten des Wellenleiters angeordneten dielektrischen Fluides,
• Figur 6 eine schematische Darstellung einer abweichend ausgestalteten Antenneneinrichtung,
• Figur 7 eine schematische Darstellung einer wiederum abweichend ausgestalteten erfindungsgemäßen Antenneneinrichtung,
• Figur 8 eine schematische Darstellung gemäß Figur 2, wobei sich die elektromagnetischen Wellen entlang von zwei ersten Bereichen mit einer ersten Permittivität in zwei verschiedenen bevorzugten Ausbreitungsrichtungen in dem Wellenleiter ausbreiten,
• Figur 9 eine grafische Darstellung einer Strahlungscharakteristik der mit einer in Figur 8 gezeigten Antenneneinrichtung in zwei bevorzugten Ausbreitungsrichtungen abgestrahlten elektromagnetischen Wellen,
• Figur 10 eine schematische Seitenansicht einer Elektrode mit einem auf beiden Seiten zinnenförmig verlaufenden Rand, und
• Figur 11 eine schematische Seitenansicht einer Elektrode mit einem auf beiden Seiten unregelmäßig wellenförmig verlaufenden Rand.

Some exemplary embodiments of the inventive concept are explained in more detail below, which are shown as examples in the drawing. It shows:

• Figure 1 a side view of an antenna device according to the invention,
• Figure 2 a sectional view through the in Figure 1 antenna device shown along the line II-II in Fig. 1 ,
• Figure 3 a schematic representation of the propagation of electromagnetic waves that are coupled into a waveguide of the antenna device via the feed device and propagate along a first region with a first permittivity in the waveguide,
• Figure 4 a graphical representation of radiation characteristics of radiated electromagnetic waves, which were produced with a prototype of the Figures 1 and 2 antenna device according to the invention shown was generated, emitted in various preferred directions of propagation and measured,
• Figure 5 a schematic top view of an antenna device according to the invention with an electrode arrangement attached to a plate of the waveguide for influencing a dielectric fluid arranged between the two plates of the waveguide,
• Figure 6 a schematic representation of a differently configured antenna device,
• Figure 7 a schematic representation of an antenna device according to the invention which is again configured differently,
• Figure 8 a schematic representation according to Figure 2 , wherein the electromagnetic waves propagate along two first regions with a first permittivity in two different preferred directions of propagation in the waveguide,
• Figure 9 a graphic representation of a radiation pattern of the with an in Figure 8 The antenna device shown emitted electromagnetic waves in two preferred directions of propagation,
• Figure 10 a schematic side view of an electrode with a crenellated edge on both sides, and
• Figure 11 a schematic side view of an electrode with an irregularly undulating edge on both sides.

In the Figures 1 and 2 a side view and a sectional view of an exemplary embodiment of an antenna device 1 according to the invention are each shown schematically. The antenna device 1 has a waveguide 2 which comprises two plates 3 arranged parallel to one another and made of a suitable electrically conductive material. The two plates 3 are each semicircular. In the area of the center of the circle of the semicircular plates 3, a feed device 4 is arranged, with which electromagnetic waves can be coupled into the waveguide 2 in order to then propagate along the waveguide 2 until the electromagnetic waves at an edge 5 of the at a distance from the feed device 4 Waveguide 2 are radiated into the free space.

A fluid made of a suitable liquid crystal material is arranged in an inner semicircular space 6. The fluid is limited to the edge 5 by a semicircular sealing ring 7 and enclosed in the intermediate space 6. From the sealing ring 7, the two plates 3 of the waveguide 2 taper continuously towards the edge 5 and form a semicircular opening slot 8, the slot width of which increases continuously with increasing distance from the center of the circle. The shape of the plates 3 in the area of the opening slot 8 at the edge 5 corresponds to the shape of a horn antenna and is intended to promote the transition of the electromagnetic wave from the waveguide 2 into the free space.

Through one in the Figures 1 and 2 control device, not shown, of the antenna device 1, the fluid in the space 6 is influenced and a first region 9 with a first, high permittivity is generated, which is delimited on both sides by a second region 10 in which the fluid has a second permittivity, which is less than the first permittivity. The electromagnetic waves coupled in by the feed device 4 preferably propagate through the first region 9 with the higher permittivity, so that the electromagnetic waves are preferably propagated and emitted in a direction of propagation predetermined by the orientation of the first region 9.

The first area 9 and the two second areas 10 are each designed as a segment of a circle and together cover the assigned semicircular segment of a circle of the waveguide 2.

In Figure 3 a simulated distribution of the electric field of the electromagnetic waves coupled into the waveguide 2 is shown as an example. It can be clearly seen that the coupled-in electromagnetic waves move almost exclusively through the first area 9 with the higher permittivity and propagate in the direction of propagation 11 specified by the arrangement of the first area 9 and are emitted by the antenna device 1. Only a small proportion of the electromagnetic waves propagates in the second regions 10 and leaves the antenna device 1 in a direction deviating from the preferred direction of propagation 11.

In Figure 4 are using a prototype of the Figures 1 and 2 Antenna device 1 shown generated and measured radiation characteristics for the emission of the electromagnetic waves are shown, three different preferred directions of propagation being specified. It can be clearly seen that the maximum radiation power is emitted in each case in the specified direction of propagation, which in the case of the in Figure 4 measurements shown were specified with 0 °, 20 ° and 70 °. The reference system for the angle ϕ of the given direction of propagation is in Figure 1 shown.

In Figure 5 an arrangement of a number of electrodes 12 on a plate 3 of the waveguide 2 is shown schematically. The individual electrodes 12 are each formed in the shape of a segment of a circle and are arranged in a fan-like manner over the entire angular range of 180 ° of the waveguide 2. A comparable electrode configuration is also arranged on the opposite plate 3. With the help of the control device, not shown, an electrical potential difference or an electrical field can be generated between mutually associated electrodes 12, which are arranged on the two plates 3, which acts on the dielectric fluid in the space between the two plates 3, for example to create a Alignment of individual liquid crystal molecules of the dielectric fluid and, consequently, the permittivity in the space 6 covered by the electrodes 12 and to be set.

The electrodes 12, which are arranged next to one another and to which a matching electrical potential is applied, form the first region 9, which specifies the preferred direction of propagation. A width of the first area 9 or an angular area that is covered by the first area 9 can be specified by the number of electrodes 12 that are assigned to the first area and correspondingly applied with a voltage. The more electrodes 12 are assigned to the first area 9 and have a corresponding voltage applied to them, the wider the first area 9. It is fundamentally possible for, for example, 180 or 360 electrodes 12 to be arranged in the angular area of 180 ° of the semicircular waveguide 2 so that a correspondingly precise specification of the first area 9 and thus a precisely adjustable and specifiable preferred direction of propagation can be specified.

In Figure 6 an exemplary embodiment of an antenna device 1 according to the invention is shown by way of example, with which only three different preferred directions of propagation can be specified. The edge 5 of the waveguide 2 is formed by three circular chords which connect to one another and also cover an angular range of 180 °. The space 6 between the two plates 3 is divided into three areas 14 by three triangular electrodes 12. Each of these three areas 14 can be configured as a first area 9 for the preferred direction of propagation or as a second area 10 by a corresponding control of the electrodes 12 with the control device in order to selectively the to be able to specify the preferred direction of propagation for the antenna device 1.

In Figure 7 an antenna device 1 according to the invention with a circular waveguide 2 is only shown schematically and by way of example. The electromagnetic waves are coupled in by a feed device 4 arranged in the center of the circle, which is arranged on an outer side 13 of a plate 3 of the waveguide 2 and couples the electromagnetic waves from the outside into the space 6 between the two plates 3. The electromagnetic waves coupled in at the center of the circle can propagate in any direction in the angular range of 360 ° covered by the waveguide 2. The preferred direction of propagation for the electromagnetic waves emitted by this antenna device 1 can be specified by means of a suitable electrode configuration.

In the Figures 8 and 9 is one different from the Figures 1 to 7 configured antenna device 1 and its radiation pattern shown schematically. Between the two plates 3 of a semicircular waveguide 2, two first regions 9 are formed which are at an angle ϕ 'measured in a counterclockwise direction or at an angle mit "measured in a clockwise direction relative to one in the Figures 8 and 9 are aligned centrally upward direction of propagation. This causes electromagnetic waves to be emitted with an in Figure 9 schematically shown radiation pattern generated, which clearly has two main emission directions.

In the Figures 10 and 11 two different exemplary embodiments for an electrode 12 are shown schematically. In the Figure 10 The electrode 12 shown in a side view has a number of crenellated projections 15 along its edges on an end face facing the viewer, so that the two edges have a crenellated curved course. The individual crenellated projections 15 are uniformly formed and arranged regularly. In the Figure 11 also in a comparable to Figure 10 The electrode 12 shown in the side view shown has along its edges on the end face facing the viewer a wave-shaped curved course 16. The wave-shaped, curved course has individual wave-shaped formations which are irregularly formed, but are arranged essentially regularly along the edges. The crenellated projections 15 and the individual wave-shaped formations could also be arranged irregularly distributed along the edges. It is also possible that one in the end views in the Figures 10 and 11 Outside of electrodes 12 arranged above and below have a correspondingly three-dimensionally structured surface. The non-linear edges and possibly the three-dimensionally structured surfaces of the electrodes 12 can cause a disruptive influence of the electromagnetic field generated between the electrodes 12, with which the first areas 9 and second areas 10 are generated and specified, on the radiation of the electromagnetic waves fed into the antenna device 1 and emitted by the antenna device 1 can be reduced or even completely prevented.

An antenna device 1 according to the invention offers great advantages when used for different communication services and communication devices and, for example, also when used in sensor technology. With the antenna device 1 according to the invention, an electrically controllable beam swiveling is possible without the use of a group antenna with the associated disadvantages. The losses that usually occur with conventional group antennas in a distribution network and in the individual phase shifters can be avoided. The antenna device 1 according to the invention can be manufactured with comparatively simple manufacturing technologies and is particularly suitable for the emission of high-frequency electromagnetic waves with a frequency of, for example, several gigahertz and more.

Claims (17)

1. Antenna device (1) for emitting electromagnetic waves, with a waveguide (2) which comprises two plates (3) of electrically conductive material arranged parallel to each other between which a dielectric material is arranged, and with an infeed device (4) with which electromagnetic waves can be coupled into the waveguide (2), which waves are then propagated along the waveguide (2) and are emitted at an edge (5) of the waveguide (2) spaced from the infeed device (4), wherein
   the dielectric material can be influenced with a control device of the antenna device (1) such that at least one first region (9) having a first permittivity and at least one second region (10) having a second permittivity is formed, wherein the first permittivity is higher than the second permittivity and wherein the antenna device is arranged such that the waves are propagated almost exclusively through the at least one first region (9) and are emitted in this preferred direction of propagation (11).
2. Antenna device (1) according to Claim 1, characterised in that the waveguide (2) is formed like a circular segment, and the infeed device (4) feeds the electromagnetic wave into the centre of the circle, and in that the at least one first region (9) and the at least one second region (10) in each case form smaller circular segments which start from the centre of the circle within the waveguide (2).
3. Antenna device (1) according to Claim 1, characterised in that the waveguide (2) has an outer peripheral edge running along a plurality of chords which adjoin each other, and the infeed device (4) feeds the electromagnetic wave in the centre of the circle, and in that edges of the at least one first region (9) and of the at least one second region (10) which start from the centre of the circle in each case run in a peripheral circle through the points of intersection of a chord which is associated with the first or second region (9, 10) .
4. Antenna device (1) according to one of the preceding claims, characterised in that the dielectric material can be influenced with the control device of the antenna device (1) such that two first regions (9) having a first permittivity and at least one second region (10) therebetween having a second permittivity are formed.
5. Antenna device (1) according to Claim 4, characterised in that the dielectric material of the at least one first region (9) is a dielectric solid, the shaping of which corresponds to the first region (9), and the orientation of which relative to the infeed device (4) can be changed.
6. Antenna device (1) according to Claim 5, characterised in that the dielectric material comprises a dielectric solid, in particular barium strontium titanate.
7. Antenna device (1) according to one of the preceding Claims 1 to 4, characterised in that the dielectric material is a fluid having an anisotropic permittivity.
8. Antenna device (1) according to Claim 7, characterised in that the control device in each case has a plurality of electrodes (12) arranged on the plates (3) of the waveguide (2) and isolated therefrom, between which electrodes an electrical field can be generated, as a result of which the permittivity of the fluid arranged between the plates (3) can be influenced and a first region (9) having a first permittivity and at least one second region (10) having a second permittivity can be specified.
9. Antenna device (1) according to Claim 8, characterised in that each electrode (12) is configured in the form of a strip or a narrow circular segment and, starting from the infeed device (4), extends to a spaced edge of the associated plate (3) of the waveguide (2).
10. Antenna device (1) according to Claim 8 or Claim 9, characterised in that each electrode (12) has along its edges a regularly or irregularly curved profile and/or a regularly or irregularly three-dimensionally structured surface.
11. Antenna device (1) according to one of the preceding claims, characterised in that the two plates (3) in an edge region (5) spaced from the infeed device (4) have a distance from each other which increases with increasing distance from the infeed device (4).
12. Antenna device (1) according to one of the preceding claims, characterised in that edge regions (5) of the two plates (3) are arranged in each case at a specified angle relative to a waveguide plane of the parallel regions of the plates (3) of the waveguide (2) such that the electromagnetic waves are emitted at an angle of between 0° and 90° relative to the waveguide plane.
13. Antenna device (1) according to one of the preceding claims, characterised in that the antenna device (1) has a plurality of waveguides (2) stacked one on top of the another, into which electromagnetic waves can be coupled by way of a common infeed device (4) or by way of a plurality of separate infeed devices (4) associated with one waveguide (2) in each case.
14. Method for emitting electromagnetic waves with an antenna device (1) according to one of Claims 1 to 11, wherein at least one first region (9) with a first permittivity and at least one second region (10) with a second permittivity is produced with the control device, so that the electromagnetic waves coupled into the waveguide (2) are propagated almost exclusively through the at least one first region (9) and are emitted in this preferred direction of propagation (11).
15. Method according to Claim 14, characterised in that the at least one first region (9) is formed like a circular segment or a triangle and the orientation of the circular segment or triangle relative to the infeed device (4) is adapted dependent on a specified direction of emission.
16. Method according to Claim 14 or Claim 15, characterised in that the at least one first region (9) is formed like a circular segment or a triangle and the angular range covered by the circular segment or triangle is adapted dependent on a specified directional focusing.
17. Method according to one of the preceding Claims 14 to 16, characterised in that a plurality of antenna devices are arranged spaced apart from each other and are operated in synchronised manner.

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