WO2001043228A1

WO2001043228A1 - Leaky wave antenna

Info

Publication number: WO2001043228A1
Application number: PCT/DE2000/004105
Authority: WO
Inventors: Thomas Hansen; Dirk Mansen
Original assignee: Robert Bosch Gmbh
Priority date: 1999-12-07
Filing date: 2000-11-21
Publication date: 2001-06-14
Also published as: DE19958750A1; DE19958750B4

Abstract

The invention relates to a leaky wave antenna (1) that allows for the electronic scanning of the antenna characteristics. The inventive leaky wave antenna (1) comprises at least one dielectric waveguide (5, 6, 7,..., 12) and irregularities (15) at which a part each of an electromagnetic field guided across the waveguide (5, 6, 7,..., 12) in the form of an electromagnetic wave (20) is emitted or received, the phase difference of the electromagnetic wave (20) between adjacent irregularities (15) being substantially equal so that a directed antenna characteristic (25, 26) is obtained. The leaky wave antenna (1) comprises means (30; 35, 36; 41, 42, 43,..., 47) for changing the spreading factor of the waveguide (5, 6, 7,..., 12). When the spreading factor is changed, the wavelength of the electromagnetic wave (20) spreading across the waveguide (5, 6, 7,..., 12) is changed, thereby also changing the phase difference that leads to a scanning of the directional antenna characteristic (25, 26).

Description

Leaky wave antenna

State of the art

The invention is based on a leaky wave antenna according to the preamble of the main claim.

From US 5 572 228 a leaky wave antenna is already known, which is realized as a mechanically swiveling antenna by allowing metal strips applied to a rotating drum to pass a dielectric waveguide. The metal strips are applied in such a way that their spacing changes when the drum rotates in the region of the dielectric waveguide, as a result of which a directed one swivels

Antenna characteristic, which is also referred to below as a directional lobe, is realized.

Advantages of the invention

The leaky-wave antenna according to the invention with the features of the main claim has the advantage that the leaky-wave antenna comprises means for changing the propagation constant of the waveguide, with a change in the propagation constant changing the wavelength of the electromagnetic wave propagating over the waveguide and thus changing the phase difference results, which leads to a pivoting of the directional antenna characteristic. In this way it is possible to electronically pivot the directional lobe to control without the need for mechanically moving parts. Due to the saving of mechanically moving parts, less space is required for the leaky wave antenna.

Compared to antenna systems without mechanical

Swiveling device, in which the individual transmission and / or reception areas are each covered by their own antenna, the power of an RF output stage during transmission being distributed to the individual antennas according to the desired antenna characteristics, results from the inventive leaky wave antenna according to the main claim of Advantage that a desired directional lobe can be pivoted by using a single antenna branch in the form of the waveguide by changing its propagation constant, so that no further antenna branches are required and space and effort are saved.

Advantageous further developments and improvements of the leaky wave antenna specified in the main claim are possible through the measures listed in the subclaims.

It is particularly advantageous that the means for changing the propagation constant comprise means for changing the effective permittivity ε _e ff for the electromagnetic wave propagating via the waveguide. It is possible to electronically pivot the directional lobe of the leaky-wave antenna via dielectric regions present on the side or in the dielectric waveguide, the relative permittivity ε _{r of} which can be controlled via an applied electrical voltage. The swivel angle of the antenna is set via the height of the electrical voltage applied to these dielectric areas. Thus, a very compact design of the antenna can be realized with a low height, the height in the is essentially determined by the control of the dielectric regions. Such a leaky wave antenna can be implemented at very low cost.

Another advantage is that the waveguide is at least partially built up in layers, the tension being introduced between the layers. In this way, the control voltage required for pivoting the directional lobe can be reduced.

It is particularly advantageous that a further dielectric rod with a relative permittivity ε _r that can be changed by applying a voltage is arranged on a side of the waveguide opposite the fault locations of the waveguide in order to control the power distribution in the leaky wave antenna, with an increase in the relative permittivity ε _{r of} the further dielectric rod, the electromagnetic wave runs more in the region of the waveguide facing the second dielectric rod, so that less power is emitted at the interference locations. Correspondingly, a reduction in the relative permittivity ε _{r of} the further dielectric rod leads to the fact that the electromagnetic wave runs more in the region of the waveguide facing away from the further dielectric rod, so that more power is applied to the

Is emitted. In this way, depending on the control of the further dielectric rod, the power radiation can be adapted to the needs of the user of the leaky wave antenna.

Another advantage is that the further dielectric rod is divided into several separate sections, the relative permittivity ε _{r of which can be} changed individually, in order to control the output at least for a part of the Realize storage locations. In this way, it is possible to reduce interfering side lobes of the desired directional lobes in terms of their performance and thus to reduce power losses when radiating RF signals and to increase the antenna gain.

Another advantage is that the means for changing the propagation constant comprise means for changing the effective permeability μ _e ff for the electromagnetic wave propagating through the waveguide. In this way, the directional lobe of the leaky wave antenna can be pivoted, for example, via magnetizable ferrite rods integrated in the waveguide. The swivel angle of the directional lobe is then determined via the strength of the magnetization and the width of the ferrite rod. In this way, too, a very compact design of the leaky wave antenna with a low overall height can be realized, the overall height being determined essentially by the control of the ferrite rod. Such a leaky wave antenna can also be realized with low production costs.

It is particularly advantageous that the means for adjusting the magnetization each switch the ferrite elements between two magnetic saturation states. With magnetization curves of ferrite elements that have a pronounced hysteresis shape that is very steep in their flanks, the magnetization of the ferrite elements between the two magnetic saturation states can be realized particularly easily, so that the directional lobe is pivoted in two stages rather than continuously can, so that you get defined operating states for the leaky wave antenna, which are very reproducible. Another advantage is that the ferrite elements are divided into sub-elements which have different cross-sectional areas and whose magnetization can be used to set a pivoting angle of the antenna characteristic which is dependent on the cross-sectional area. In this way, depending on these cross-sectional areas, swivel angle increments can be specified, which allow a multi-stage swiveling of the directional lobe with different swivel angles.

It is also advantageous that the means for adjusting the magnetization of the ferrite elements continuously control the magnetization of the ferrite elements between two magnetic saturation states. In this way, an analog swiveling behavior of the directional lobe, in which the

Directional lobe between two magnetic saturation states associated limit angles can take any pivot angle.

Another advantage is that the ferrite elements are ring-shaped and that the means for adjusting the magnetization of the ferrite elements each comprise a conductor through which a current is wound around the corresponding ferrite element and which induces a magnetic field in the corresponding ferrite element. In this way, a particularly simple control for setting the magnetization of the ferrite elements is made possible, which essentially does not require any additional space.

Another advantage is that the interference locations are arranged on opposite sides of the waveguide, so that there is a uniform radiation and / or reception behavior of the leaky wave antenna. Another advantage is that an antenna array is formed from several waveguides arranged in parallel and fed by a common distribution network. In this way, the antenna characteristics can be focused in a plane orthogonal to the waveguides without the need for expensive and usually large lenses.

Another advantage is that a phase shifter is assigned to at least some of the waveguides. In this way, the antenna characteristic in the plane orthogonal to the waveguides depending on the respective realized by the phase shifter

Phase shift of the electromagnetic wave guided in the respective waveguides are pivoted.

It is particularly advantageous that the means for changing the propagation constant of the waveguide in a region at one end of the respective waveguide that the

Distribution network is assigned, separately control the propagation constant to cause a phase shift between the individual waveguides. In this way, no separate phase shifters are required, so that space, costs and material can be saved.

Another advantage is that the magnetization of ferrite elements of different waveguides that are to be controlled in the same way are combined and controlled together. In this way, a more precise and less complex control of ferrite elements to be controlled in the same way can be realized, so that ferrite elements to be controlled in the same way are really controlled in the same way and not only slightly differently from one another. A particularly compact and material-saving solution results from the fact that several identically controlled ferrite elements are combined to form a common ferrite ring in the area of mutually corresponding storage locations of several waveguides arranged in parallel. Particularly when the magnetization of such a ferrite ring is actuated by a current-carrying conductor wound around the ferrite ring, the actuation can be implemented simultaneously for several waveguides with particularly little effort.

Another advantage is that one or more reflection surfaces are arranged on at least one side of the at least one waveguide. In this way, the antenna gain can be increased.

Another advantage is that additional storage locations are arranged below, on the side of the waveguide facing away from the storage locations. In this way, an improvement in the radiation and / or reception properties can be achieved, in particular when interacting with the reflection surfaces.

drawing

Exemplary embodiments of the invention are shown in the drawing and explained in more detail in the following description. FIG. 1 shows a block diagram of a leaky wave antenna, FIG. 2 shows a dielectric waveguide with storage locations designed as metal strips, FIG. 3 shows an antenna array without phase shifters, FIG. 4 shows an antenna array with phase shifters, FIG. 5 shows a dielectric waveguide with storage locations designed as dielectric grooves, and FIG. 6 shows a leaky wave antenna with controllable dielectric rods arranged on the side of the waveguide, FIG. 7 with a leaky wave antenna an additional controllable dielectric rod arranged underneath the waveguide, FIG. 8a) an example of a horizontally slowly layered material, FIG. 8b) an example of a vertically slowly layered material and FIG. 8c) an example of a horizontally layered material, FIG. 9 a leaky wave antenna with horizontally slowly layered sides 10 shows a controllable dielectric rods arranged on the waveguide, FIG. 10 shows a leaky wave antenna with a controllable dielectric waveguide that is vertically slice-layered,

Leaky wave antenna with a cross-layered dielectric rod arranged underneath the waveguide, FIG. 12 shows a spin electron in a magnetized ferrite material, FIG. 13 shows circular polarization regions of the H field of an electromagnetic wave in the leaky wave antenna, FIG 14 shows an arrangement of ferrite elements not divided into partial elements in the leaky wave antenna for continuous control of the ferrite elements between two saturated states, FIG. 16 shows a leaky wave antenna with rectangular ferrite rings, FIG. 17 shows an antenna array with ferrite rings combined for several waveguides, FIG. 18 shows a leaky wave antenna with storage locations on opposite sides of the waveguide, FIG. 19 shows an antenna array with two orthogonal swivel planes for the directional lobes and phase integrated in the waveguide FIG. 20 shows a directional radiation of a leaky wave antenna with several storage locations, FIG. 21 shows an alternating activation of layered controllable dielectric material, FIG. 22 shows a relationship between the phase difference between two storage locations and the resulting swivel angle of the directional lobe, FIG. 23 shows an example of a magnetization curve for ferrite material and FIG. 24 shows a representation for defining a swivel angle range.

Description of the exemplary embodiments

FIG. 1 schematically shows an arrangement of a leaky wave antenna 1, which comprises a dielectric waveguide 5 and is fed by a distribution network 85 with RF signals for radiation. RF signals received by the leaky wave antenna 1 via the waveguide 5 are supplied in reverse to the distribution network 85 and are fed from there for further processing. The waveguide 5 has a first directional antenna characteristic 25 in the form of a first directional lobe. Furthermore, a control unit 30 is provided which controls the waveguide 5 in such a way that the first directional lobe 25 can be pivoted in two opposite directions by a pivoting angle φ.

The RF signals are fed in or out via the distribution network 85 at a narrow end 115 of the waveguide 5 designed as an elongated cuboid.

In Figure 2, the waveguide 5 forming the leaky wave antenna 1 is shown in an oblique view. The

Waveguide 5 has on one of its surfaces in the longitudinal direction according to FIG. 2 four storage locations 15 as storage strips transverse to the longitudinal direction. The storage locations 15 can be metal strips as indicated in FIG. 2 or dielectric grooves as indicated in FIG. 5.

Crucial for the formation of a directional antenna characteristic, such as the first directional lobe 25 in the plane of the waveguide 5 according to FIG. 1 and Figure 20 is that adjacent storages 15 are equidistant. This results in the same phase difference between two mutually adjacent fault locations 15 for the electromagnetic field in the form of an electromagnetic wave 20 as shown in FIG. 13, which results from the feeding or reception of an RF signal and runs in the waveguide 5. Part of the fed-in RF signal is emitted or an RF signal is received at the fault locations 15. On the basis of the same phase difference of the electromagnetic wave running in the waveguide 5 between adjacent storage locations 15, the first directional antenna characteristic 25 is then effected in the plane of the waveguide 5 according to FIG. 1 and FIG. 2. This first directional antenna characteristic 25 is shown in more detail in FIG. It can be seen that the first directional antenna characteristic 25 comprises a main lobe 100 and a plurality, for example four, in accordance with FIG. 20, side lobes 105.

In FIG. 24, the same reference numerals designate the same elements as in FIG. 20, the figure starting from the illustration of the first directional lobe 25 in FIG

24 shows a swivel angle range 110 within which, by electronically actuating the waveguide 5, a swivel angle φ for swiveling the first directional lobe

25 can be set. FIG. 24 also shows the coupling of an RF signal at a narrow end 115 of the waveguide 5 for the transmission operating mode, as also shown in FIG. 1.

For the electronic control of the waveguide 5 for pivoting the first directional lobe 25 by means of the control unit 30, a control voltage U _{t t} supplied by the control unit 30 to the leaky wave antenna 1 is shown in FIG. 1. In FIG. 3, the same reference numerals designate the same elements as in FIG. 1. According to FIG. 3, the RF signal, for example coming from an RF output stage, is fed into the distribution network 85 in order to be radiated by the leaky wave antenna 1. Conversely, an RF signal is received by the leaky wave antenna 1, the received RF signal being forwarded via the distribution network 85 to further circuits for processing the received RF signal, for example by mixing, by demodulation, by decoding, etc. An antenna switch can be connected upstream of the distribution network 85 in order to separate the send and receive directions. According to FIG. 3, the leaky wave antenna 1 now comprises a plurality of waveguides 5, 6, 7, 8, 9, 10, 11, 12 arranged parallel to one another. These each include, by way of example, sixteen fault locations 15. Each of the waveguides 5, 6, 7, ..., 12 is connected via a narrow-side end 115 to the distribution network 85 for supplying or receiving RF signals. The waveguides 5, 6, 7, ..., 12 are of equal length and comprise the same number of interference points 15, the interference points 15 of adjacent waveguides also being adjacent to one another, so that in the example according to FIG. 3 eight identical waveguides 5, 6, 7, ..., 12 are present, which have given the same positions for their storage locations 15. An antenna array 80 is formed by the waveguides 5, 6, 7,... 3, in which the same reference numerals designate the same elements as in the other figures, in addition to the first directional lobe 25, a second directional lobe 26 orthogonal to the plane of the waveguides 5, 6, 7,... 12 is focused. In contrast to the first directional lobe 25, the second directional lobe 26 in the arrangement according to FIG. 3 is fixed and not pivotable. To pivot the first directional lobe 25 by the pivot angle φ, the control unit 30 controls the individual waveguides 5, 6, 7,..., 12 in the manner described with reference to FIG. 1 by means of the control voltage Us.

In FIG. 4, the same reference numerals designate the same elements as in FIG. 3. Starting from FIG. 3, the waveguides 5, 6, 7, ..., 12 of the antenna array 80 are each connected via a phase shifter 91, 92, 93, ..., 98 the

Distribution network 85 connected. The phase shifters 91, 92, 93, .., 98 are each connected to the narrow-side end 115 of the corresponding waveguide 5, 6, 7, ..., 12, which faces the distribution network 85. Depending on the setting of the phases on the individual phase shifters 91, 92, 93, ..., 98, a different phase shift of the electromagnetic wave running in the individual waveguides 5, 6, 7, ..., 12 can be achieved, resulting in a certain pivot angle of the second beam 26 guide. If the phase of one or more of the phase shifters 91, 92, 93,..., 98 is changed, the phase delay of the respective electromagnetic wave running there and thus the pivot angle p of the second directional lobe 26 on the associated waveguide changes the second directional lobe 26 can thus be effected by changing the setting of the phase of at least one of the phase shifters 91, 92, 93, ..., 98. For this purpose, the phase shifters 91, 92, 93, ..., 98 are to be controlled accordingly, for example also via the control unit 30. According to the embodiment according to FIG. 4, both the first directional lobe 25 and the second directional lobe 26 can thus be pivoted.

The following is the control of a dielectric waveguide to pivot it in the plane of the The first directional lobe 25 lying on the waveguide is explained in more detail by way of example on the first dielectric waveguide 5 of the antenna array 80. It is possible to use the radiated power of the individual interference locations 15 of the first dielectric waveguide 5 when using

Specify metal strips across their width or, when using dielectric grooves, their height and length. In this way, by means of a suitable choice of the radiated power at each fault location 15, directional radiation with low side lobes 105 can be implemented in order to save power and reduce interference.

The direction of the radiation is dependent on the distance between the storage locations 15. Because of the distance of the

Interference points 15 determine the phase position which is present at the emitting or receiving interference points 15 from the electromagnetic wave guided in the first dielectric waveguide 5. FIG. 22 shows the relationship between the phase position and the swiveling angle φ that arises using the simple example of blind spots 15 designed as isotropic omnidirectional radiators. Equation (3) represents the mathematical relationship. The swivel angle φ is calculated using:

d_ dg = 2π λ

With

λ = - (2)

/

from this follows the swivel angle φ φ = arcsin = arcsin Pθ (3) dθ 2π

CQ is the speed of light in a vacuum, f is the frequency of the electromagnetic wave, dg is the phase distance between two adjacent interference locations 15 on the first dielectric waveguide 5 based on the free-space wavelength and PQ is the phase difference of the electromagnetic wave between the two adjacent interference locations 15 in the first dielectric waveguide 5 Thus, in order to achieve the pivoting of the first directional lobe 25 of the leaky wave antenna 1, the phase difference PQ must be changed in the waveguide 5 between adjacent fault locations 15. This can be achieved, on the one hand, and as described in US Pat. No. 5,572,228, by changing the spacing of the storage locations 15 in a constant manner. According to the invention, the phase difference P9 between adjacent fault locations 15 can also be realized by influencing the propagation constant which the electromagnetic wave experiences in the first dielectric waveguide 5 and around the first dielectric waveguide 5. For the ideal case of lossless materials, the propagation constant consists of the phase measure ß, which indicates the phase change in the electromagnetic wave per unit length. In general, the phase measure is calculated

2π_ ß 2π - f -. μ hast ^ε e [λ

In equation (4), μ _e ff denotes the effective permeability that the electromagnetic wave as a whole experiences inside and outside the first dielectric waveguide 5, ε _e ff the effective permittivity that the electromagnetic wave as a whole inside and outside the first dielectric waveguide 5, λ the wavelength of the electromagnetic wave and f the frequency of the electromagnetic wave. A change in the phase difference PQ between adjacent fault locations 15 can also be achieved by changing the phase dimension β, which results in the following

ΔPθ = Δß ^• d (5)

In equation (5), ΔPθ denotes the change in the phase difference PQ between adjacent fault locations 15, d the distance between adjacent fault locations 15 and Δß the change in the phase dimension β.

The change ΔPθ in the phase difference PQ then leads to a changed pivot angle φ in accordance with equation (3).

The method described last is particularly suitable for the electronic pivoting of the first directional lobe 25 of the leaky wave antenna 1.

The propagation constant of the electromagnetic wave propagating in the first dielectric waveguide 5 of the leaky wave antenna 1 can be influenced, inter alia, by changing the effective permittivity ε _e ff that the electromagnetic wave experiences. This requires a dielectric material that has a variable relative permittivity ε _r . There are materials that meet these requirements. Such a material is, for example, BSTO (barium strontium titanate), PZT (lead zircon titanate) or a material formed at least partially from one of the substances mentioned. The relative permittivity ε _{r of} such materials can be determined by applying the electrical control voltage Ug-f- and thereby change caused electric field. This behavior can now be used as follows:

The first dielectric waveguide 5 of the leaky wave antenna 1 can be made directly from such a dielectric material with variable relative permittivity ε _r , or parts of the first dielectric waveguide 5 can be replaced by this material. By changing the relative permittivity ε _r , in accordance with equation (4) and equation (5), changed phase relationships are achieved at the emitting or receiving jamming points 15 and thus, according to equation (3), the directional radiation or the first directional lobe 25 is pivoted.

The electromagnetic wave does not only exist within the first dielectric waveguide 5 of the leaky wave antenna 1, but to a not insignificant extent also outside in the immediate vicinity of the first dielectric waveguide 5.

Therefore, according to FIG. 6, it is also possible to cause rods 35, 36 to be attached to the first dielectric waveguide 5 to bring about a change in the effective permittivity ^ε eff, which acts on the electromagnetic wave when these rods 35, 36 are formed from dielectric material, whose relative permittivity ε _r can be changed. According to equations (4), (5) and (3), with such a change in the relative permittivity ε _r, the rod 35, 36 and thus the effective permittivity ε _e ff again have correspondingly changed phase relationships between the emitting or receiving locations 15 and this results in the first directional lobe 25 of the leaky wave antenna 1 being pivoted. According to FIG. 6, the rods 35, 36 are on opposite longitudinal sides of the first dielectric Waveguide 5 is arranged, wherein this first dielectric waveguide 5 aquidistant in the longitudinal direction on a surface that connects the two long sides with the rods 35, 36, six storage points 15.

It is sufficient to arrange such a dielectric rod with variable relative permittivity ε _r only on one long side of the first dielectric waveguide 5.

A further dielectric rod 40 with variable relative permittivity ε _r can be arranged in order to control the power radiation in the leaky wave antenna 1 on an underside of the first dielectric waveguide 5 opposite the surface with the locations 15. If the relative permittivity ε _{r of} this further dielectric rod 40 on the underside of the first dielectric waveguide 5 is increased, then the electromagnetic wave will run more in the region of the first dielectric waveguide 5 facing the further dielectric rod 40, so that less power at the storage locations 15 is emitted. Correspondingly, when the relative permittivity ε _{r of} the further dielectric rod 40 is reduced, the electromagnetic wave 20 will run more in the region of the first dielectric waveguide 5 facing away from the further dielectric rod 40 and thus facing the storage locations 15, so that more power is radiated at the storage locations 15 becomes.

It is also possible to divide the further dielectric rod 40 on the underside of the first dielectric waveguide 5 into a plurality of sections which are separate from one another and whose respective relative permittivity ε _{r can be} individually changed or controlled by an individual one To implement power control at least for some of the storage locations 15. It can also be provided that the further dielectric rod 40 is divided into separate sections such that each individual storage location 15 or a part of the storage locations 15 is assigned its own section, the relative permittivity ε _{r of which can be} changed individually, so that for the corresponding storage location 15 an individual power control is realized. In this way, for example, side lobes 105 can be reduced in the radiation from the corresponding storage locations 15. Furthermore, it can be provided to arrange a dielectric rod 35, 36 with variable relative permittivity ε _r on at least one longitudinal side of the waveguide 5 and to arrange the further dielectric rod 40 on the underside of the first dielectric waveguide 5 in order to combine the associated and described effects with one another to combine.

In order to change the relative permittivity ε _{r of} a dielectric material with controllable or changeable relative permittivity ε _r , the control voltage Ug _t , which introduces a static electric field into the dielectric material, is required. The required control voltage Ugt is greater the thicker the dielectric material. Some applications for the leaky wave antenna 1, such as in the automotive field, only provide small control voltages Ug _t , which could not be sufficient for the first directional lobe 25 of the leaky wave antenna 1 to pivot sufficiently. The electrical control voltage Ug- _j - is electronically regulated by the control unit 30 and made available. This is because the maximum swivel angle for swiveling the first directional lobe 25 depends on the relative permittivity ε _r and the thickness d of the corresponding dielectric material. The effective permittivity ε _e ff results from the product of the relative permittivity ε _r with the permittivity εg in a vacuum. The relative permittivity ε _r is changed by an external static electric field. The static electric field depends on the applied control voltage U ^ - ^and the thickness of the dielectric material

E = ^ (6)

from.

In equation (6) E denotes the electric field strength of the applied static electric field, Ug _t the control voltage applied across the thickness of the dielectric material via electrodes and d the thickness of the dielectric material with variable relative permittivity ε _r . Thus, for a given control voltage U ^ the thickness d of the dielectric material influences the resulting electric field strength E of the applied static electric field, the electric field strength E influencing the relative permittivity ε _{r of} the dielectric material and this in turn influences the pivot angle of the first directional lobe 25 via the equations (4), (5) and (3). The maximum adjustable swivel angle φ of the first straightening lobe 25 is thus limited by the thickness d of the dielectric material. For a given thickness d, only a certain electric field strength E can be set for a given control voltage Ugt-. The achievable swivel angle φ of the first directional lobe 25 is limited in this way. With the aid of dielectric material built up in layers with changeable relative permittivity ε _r , the required control voltage Ug _t can be reduced. The control voltage Ug- ₍ - is introduced between the layers 50, 51 thus created in accordance with FIG. 21. The control voltage Ug _t can be applied to the individual layers 50, 51, for example, via metallic electrodes. The control voltage Ug _t can be applied to the individual layers 50, 51 can also be applied over semiconductor layers, each of which is inserted into the dielectric material at the boundary between two adjacent layers 50, 51. It can also be provided to form adjacent layers 50, 51 with different dielectric material, each of which is in its relative permittivity ε _{r is} changeable

Control voltage Ug- _j - can then be applied to the individual layers 50, 51 via conductive boundary layers between adjacent layers 50, 51 to the individual layers 50, 51.

In general, the thickness d of the dielectric material required for the leaky wave antenna 1 is divided into much thinner layers 50, 51. Now the individual layers 50, 51 can each be driven with the same control voltage Ug ^ if adjacent layers 50, 51 are driven in opposite polarity, as shown in FIG. This layer-by-layer control of the dielectric material can be used both in the waveguide 5 itself, as shown in FIG. 21, and in the dielectric rods 35, 36 which are optionally arranged on the longitudinal sides of the waveguide 5 and the further dielectric rod 40 which is optionally arranged on the underside of the waveguide 5 , According to FIG. 8a), the example of the first dielectric waveguide 5 shows a horizontally slow-layered dielectric material with mutually adjacent layers 50, 51. In FIG. 8b), using the first dielectric waveguide 5 as an example, a vertically slow-layered dielectric material with mutually adjacent layers 50, 51 is shown. According to FIG. 8 c), a cross-layered dielectric material with mutually adjacent layers 50, 51 is shown using the example of the first dielectric waveguide 5. Because of

For clarity, only individual ones of the adjacent layers are identified by reference numerals in all figures, in which layered dielectric materials are shown.

The described longitudinal or transverse layering of the dielectric material can be applied both to the dielectric rod 35, 36 on the long sides of the waveguide 5 and to the further dielectric rod 40 on the underside of the first dielectric waveguide 5 and finally also in the first dielectric waveguide 5 itself deploy.

FIG. 9 shows an example of a first dielectric waveguide 5 with six storage locations 15 designed as metal strips and the dielectric rods 35, 36 with a horizontally slow-layered structure on the two long sides of the first dielectric waveguide 5.

FIG. 10 shows the first dielectric waveguide 5 as a vertically slow-layered dielectric waveguide with likewise six storage locations 15. The first dielectric waveguide 5 can itself be made up of dielectric rods with variable relative permittivity ε _r by the vertical to achieve slow stratified construction. However, it does not necessarily have to be constructed in its entire width from dielectric rods, but can also consist of dielectric rods only in partial areas.

FIG. 11 shows, as an example, the first dielectric waveguide 5 with six storage locations 15 designed as metal strips and the further dielectric rod 40 with a cross-layered structure arranged on the underside of the first dielectric waveguide 5.

The number of storage locations 15 is not limited to four or six, as selected in the examples, but is arbitrary. The number of storage locations 15 determines the opening angle of the main lobe 100 and can be selected according to the system requirement. The more blind spots 15 are provided with a constant distance between two adjacent blind spots 15, the narrower the main lobe 100.

If the leaky wave antenna 1 is operated freely in space, it does not only radiate in the direction of use as indicated in FIG. 20. The leaky wave antenna 1 radiates just as strongly in the opposite direction. This radiation is not desirable in most applications and significantly reduces the antenna gain in the direction of use.

A higher gain of the leaky wave antenna 1 is therefore achieved by arranging one or more reflecting surfaces on the side of the first dielectric waveguide 5 facing away from the interference locations 15 and / or on at least one long side of the first dielectric waveguide 5. The unwanted radiation is reflected by the reflective surfaces in the direction of use. The reflective surfaces must be positioned and shaped in this way be that the reflected radiation overlaps the radiation in the direction of use so that no deformation of the radiation characteristic occurs in the direction of use.

The fields of application of the leaky wave antenna 1 described are antenna systems which have to be pivoted in at least one plane. Such an antenna system with additional directional radiation orthogonal to the plane of the waveguides 5, 6, 7, ..., 12 of the leaky wave antenna 1 is described in accordance with FIG. 3. An example of one

Antenna system with additional swiveling possibility orthogonal to the plane of the waveguides 5, 6, 7, ..., 12 of the leaky wave antenna 1 is described in accordance with FIG. 4.

It should be taken into account that, according to FIG. 19, in which the same reference numerals designate the same elements as in FIGS. 3 and 4, the phase shifters 91, 92, 93,..., 98 also in the region of the respective dielectric waveguide facing the distribution network 85 5, 6, 7, ..., 12 can be integrated. For this purpose, a part in the

Distribution network 85 facing area of the corresponding dielectric waveguide 5, 6, 7, ..., 12 used with the aid of the dielectric material, which can be changed in its relative permittivity ε _r , to achieve the desired phase shift between the individual waveguides 5, 6, 7, .., 12 to generate.

The corresponding control of this respective part of the eight waveguides 5, 6, 7, ..., 12 is also carried out by the control unit 30 and the like

_{Phase control voltages} V _stj _ i = 1, 2, ..., 8 according to FIG. 19. Different phase control voltages V _s ti can result in different phase shifts of the electromagnetic waves in the individual waveguides 5, 6, 7, ..., 12 and thus lead to any adjustable pivoting angles of the second directional lobe 26.

It can also be provided to combine the embodiment according to FIG. 19 with the embodiment according to FIG. 4 and part of the waveguides 5, 6, 7, ..., 12 with integrated adjustable phase shift according to FIG. 19 and part of the waveguides 5, 6 , 7, ..., 12 to be provided with an externally adjustable phase shift by means of an external phase shifter according to FIG. 4.

It can further be provided that one or more of the waveguides 5, 6, 7, ..., 12 is provided without a phase shifter or integrated phase shift according to the embodiment according to FIG. 4 or according to FIG. 19, so that the electromagnetic wave in this waveguide or cannot be delayed in phase in these waveguides.

According to the invention, an electronically pivotable leaky wave antenna is thus realized, which is inexpensive and space-saving and can be used universally in adaptive antenna systems. The leaky wave antenna 1 can also be used in high-resolution, imaging radar systems. Furthermore, use is possible in all systems in which a certain spatial area has to be scanned 2 or 3 dimensionally for the reception of HF signals by the leaky wave antenna 1.

A second exemplary embodiment for changing the propagation constant in the first dielectric waveguide 5 is described below. From phase shifter applications, for example according to the publication “Microwave and Millimeter Wave Phase Shifters, Volume I, Dielectric and Feritte Phase Shifter ", Shiban K. Koul, Bharathi Bhat Artech House 1991, it is known that magnetized ferrites can be used to influence the propagation constant for an electromagnetic wave.

The magnetic properties of ferrites are caused, inter alia, by spin electrons 120 according to FIG. 12. They are particularly important for the function of the leaky wave antenna 1 described in this second example.

FIG. 12 shows an arbitrary spin electron 12 in a magnetized ferrite material. Due to its own rotation, this spin electron 120 has a certain magnetic dipole moment m. If a magnetic field H _Q according to FIG. 12 is brought into the ferrite material

If the direction of the z axis of a three-dimensional Cartesian coordinate system whose direction does not match the magnetic dipole moment m, the spin electron 120 goes into an attempt to align itself in the direction of the introduced magnetic field Ho

Gyroscopic movement T according to FIG. The axis of rotation of the gyro movement points in the direction of the introduced magnetic field H _Q.

This behavior within the ferrite material is now used as follows:

If a high-frequency magnetic field is introduced into such a magnetized ferrite material, the vector of which rotates in the same plane in which the magnetic dipole moment m of the spin electrons 120 performs its gyroscopic movement, there is an interaction between the high-frequency magnetic field and the ferrite material. Is the direction of rotation correct? of the high-frequency magnetic field vector coincides with the direction of the gyroscopic movement of the dipole moment m of the spinel electrons 120, the interaction results in a low effective permeability μ _e ff for the high-frequency magnetic field. If the magnetic field H _Q introduced into the ferrite material is turned over, the magnetic field is also reversed

Direction of rotation of the spin movement of the spin electrons 120 µm. Now the direction of rotation of the high-frequency magnetic field vector is opposite to the direction of the gyroscopic movement and the interaction causes a higher effective permeability μ _e ff for the high-frequency magnetic field.

In the first dielectric waveguide 5 there are areas in which the high-frequency magnetic field vector of the propagating electromagnetic wave 20 according to FIG. 13 rotates almost uniformly in the yz plane of the Cartesian coordinate system. 13, first areas 125 are arranged on an upper side 135 of the first dielectric waveguide 5, whereas second areas 130 are arranged on an underside 140 of the first dielectric waveguide 5. Corresponding arrows indicate in FIG. 13 that the high-frequency magnetic field vector rotates on the left in the first areas 125, whereas it rotates on the right in the second areas 130. The first areas 125 is on the

Upper side 135 of the first dielectric waveguide 5 each assigned a storage location 15. In this example, according to FIG. 13, uniform rotation is understood to mean a rotation of the high-frequency magnetic field vector in the same direction, so that both the first regions 125 with one another and the second regions 130 with one another are characterized by uniform rotation of the high-frequency magnetic field vector are. The electromagnetic wave 20 moves in the z direction through the first dielectric waveguide 5. In this first areas 125 and second areas 130 are introduced over the entire width of the first dielectric waveguide of the leaky wave antenna 1 ferrite rod 41, 42, 43, ..., 47, Figure 13 showing a longitudinal section through the first dielectric waveguide 5, so that the Plane of the drawing is perpendicular to the broad side of the first dielectric waveguide 5. The ferrite rods 41, 42,..., 47 are thus aligned perpendicular to the plane of the drawing in the x direction according to FIG. 14, which also shows a longitudinal section through the first dielectric waveguide 5, in the first dielectric waveguide 5.

According to FIG. 13 and FIG. 14, the x axis of the Cartesian coordinate system points perpendicularly into the plane of the drawing. In FIGS. 14, 15 and 18, a point represents a direction perpendicular into the plane of the drawing and a cross represents a direction perpendicularly out of the plane of the drawing. According to FIG. 14, the ferrite rods 41, 42, 43 located in the first regions 125 are magnetized in the x direction perpendicular to the plane of the drawing. The ferrite rods 44, 45, 46, which are arranged in the second regions 130, on the other hand, are magnetized in the opposite direction, that is to say perpendicularly out of the plane of the drawing. The gyroscopic movement of the spin electrons 120 caused by the respective magnetic field in the individual ferrite rods 41, 42, 43, 44, 45, 46 is then opposite to the direction of rotation of the high-frequency magnetic field vectors both in the first regions 125 and in the second regions 130 Figure 13. In the case of a left-turning high-frequency magnetic field vector, the axis of rotation points perpendicularly out of the plane of the drawing opposite to the x direction, whereas in the case of a right-turning high-frequency magnetic field vector, the axis of rotation points in the x direction. The electromagnetic wave 20 then experiences an increased effective permeability μ _e ff - according to equations (4) and (5) The phase difference PQ of mutually adjacent storage locations 15 thus increases. This increases the swivel angle φ in accordance with equation (3), so that the first directional lobe 25 swings to the left in accordance with FIG.

If the direction of the magnetic field introduced into the ferrite rod 41, 42, 43, 44, 45, 46 is reversed, the gyroscopic movement of the spin electrons 120 also reverses. The direction of rotation of the gyroscopic movement now coincides with the direction of rotation of the high-frequency magnetic field vector both in the first regions 125 and in the second regions 130. The electromagnetic wave now experiences a lower effective permeability μ _e ff. From this, according to equations (4) and (5), there follows a reduced phase difference PQ between adjacent fault locations 15, so that the swivel angle φ is reduced according to equation (3) and the directional lobe 22 pivots to the right.

The magnitude of the effective permeability μeff that arises depends on the strength of the magnetization of the corresponding ferrite rod 41, 42, 43, 44, 45, 46. FIG. 23 shows an example of a magnetization curve of a ferrite material. The maximum magnetization of the ferrite material is a positive saturation magnetization 65 and a negative magnetization

Saturation magnetization 70. For these two values, the lowest and the highest adjustable effective permeability μ _e ff are reached. These limit values thus determine the maximum swivel angle range 110 according to equation (4) and (5) according to FIG. 24. A swivel angle φ within the swivel angle range 110 is achieved by setting a magnetization which lies between the two saturation magnetizations 65, 70 of the ferrite material according to FIG. 23. So there is a possibility that to continuously pivot the first directional lobe 25 of the leaky wave antenna 1 in the swivel angle range 110.

It is not necessary that the full

Swivel angle range 110 is used according to Figure 24. Applications are conceivable in which the swivel angle φ lies only in a positive part 111 of the swivel angle range 110 or only in a negative part 112 of the swivel angle range 110.

For most applications, however, it is not necessary to continuously pivot the first beam 25 as described. It is then entirely sufficient if the first directional lobe 25 can assume discrete swivel angles φ. This leads to the process of digitally pivoting the first directional lobe 25. For this purpose, the entire pivoting angle range 110 is divided into, for example, equally large angle ranges. These angular ranges determine the smallest angle by which the first directional lobe 25 has to be pivoted.

One implementation is such that the ferrite rods 41, 42 shown in FIG. 14 on the top 135 of the first dielectric waveguide 5, that is to say in the first regions 125 according to FIG. 13, which according to FIG. 14 are each assigned to a location 15 in several partial ferrite rods 71, 72, 73, 74 with differently sized and separate cross-sectional areas according to FIG. 15. A first ferrite rod 41 is divided on the top 135 of the first dielectric waveguide 5 into a first partial ferrite rod 71 and a second partial ferrite rod 72. A second ferrite rod 42 on the top 135 of the first dielectric waveguide 5 is divided into a third partial ferrite rod 73 and a fourth partial ferrite rod 74 according to FIG. 15. The cross section 15 of the second partial ferrite rod 72 is chosen to be as large as the cross section of the fourth partial ferrite rod 74 and half as large as the cross section of the first partial ferrite rod 71 and the third partial ferrite rod 73.

The cross-sectional sizes of the partial ferrite rod 71, 72, 73, 74 must be designed such that when the partial ferrite rod 72, 74 with the smallest cross-sectional areas are switched between their positive saturation magnetization 65 and their negative saturation magnetization 70, the first directional lobe 25 by the smallest predetermined swivel angle φ swings. The partial ferrite rod 71, 73 with the next larger cross-sectional areas must now be designed in their cross-sectional area such that when they are switched in their magnetization between their positive saturation magnetization 65 and their negative saturation magnetization 70, the first directional lobe 25 is pivoted by twice the smallest predetermined angle , This is correspondingly represented by the double cross-sectional area as described in FIG. 15. Part ferrite rod, which are not shown in Figure 15, and their

Cross-sectional areas are even larger than those described, must be designed in their cross-sectional area so that the first directional lobe 25 can pivot four times, eight times, etc. of the smallest predetermined angle, the cross-sectional areas corresponding to four times, eight times, etc. Cross-sectional area of the second partial ferrite rod 72 must correspond. The described linear relationship between cross-sectional area and swivel angle is chosen for illustration. As a rule, there will be no linear relationship between the cross-sectional area of the partial ferrite rod and the pivot angle that can be realized with it, so that doubling the pivot angle does not mean doubling the Cross-sectional area of the corresponding partial ferrite rod must go hand in hand. It is also possible that

To choose cross-sectional areas of the partial ferrite rod so that any integer or real multiples of the smallest possible swivel angle can be realized.

The magnetization of the ferrite rod 41, 42, 43, 44, 45, 46 is decisive for the function of the leaky wave antenna 1 in the described second example. It can be done, for example, by the ferrite rod 41, 42, 43, 44, 45, 46 , 47 closes at both ends to form a rectangular ring according to FIG. 16 and induces a magnetic field via a current-carrying conductor wound around the resulting ferrite ring, so that the desired magnetization is achieved by correspondingly controlling the current flow through the conductor.

FIG. 16 shows a practical embodiment of the first dielectric waveguide 5 with four storage locations 15 on its top 135 and closed to form ferrite rings

Ferrite rods 41, 42, ..., 47, which are designed for digital pivoting of the first directional lobe 25 as partial ferrite rods 71, 72, ..., 76 which are closed to form partial ferrite rings.

For use in the antenna array 80, the ferrite rod 41, 42, ..., 47 or the partial ferrite rod 71, 72, ..., 76 of adjacent dielectric waveguides 5, 6, 7, ..., 12 according to FIG Waveguides 5, 6, 7, 8 adjacent storage locations 15 are combined and, for example, are also each closed to form a ferrite ring or partial ferrite ring. According to FIG. 17, this is based on a 4X4 antenna array 80 consisting of four dielectric waveguides 5, 6, 7, 8, each with four blind spots 15 designed as metal strips for digitally pivoting the first directional lobe 25, that is to say using the Part ferrite rod 71, 72, .., 76 shown in the form of part ferrite rings. According to FIG. 17, the magnetization of ferrite rods 41, 42, 43, ..., 47 or partial ferrite rods 71, 72, 73, ..., 76 of different waveguides 5, 6, 7, 8, which are to be driven in the same way, are combined and together by each controlled a current-carrying conductor, not shown, wound around the corresponding ferrite or partial ferrite ring. In this case, as shown in FIG. 17, a plurality of ferrite rods 41, 42, 43, ..., 47 or partial ferrite rods 71, 72, 73, ..., 76, which are driven in the same way, can each be located in the area on adjacent waveguides 5, 6, 7, 8 corresponding fault locations 15 can be combined to form a common ferrite ring or partial ferrite ring, the waveguides 5, 6, 7, 8 being arranged in parallel as shown in FIG.

In this second exemplary embodiment, too, the storage locations 15 can be designed both as metal strips and as dielectric grooves. It can also be provided both in the first and in the second exemplary embodiment that some of the gaps 15 of the first dielectric waveguide 5 are designed as dielectric grooves, whereas other gates 15 of the first dielectric waveguide 5 are designed as metal strips. The number of store locations 15 is also not limited to four, but is arbitrary. As described, the number of storage locations 15 determines the opening angle of the main lobe 100 and can be selected in accordance with the system requirement. The more blind spots 15 are present with the same blind spot spacing from one another, the narrower the main lobe 100 becomes.

Both in the first and in the second exemplary embodiment, all dielectric waveguides and / or their Dielectric rods 35, 36 arranged on one or both long sides can be driven with the same control voltage Ug- £ as possible so as not to impair the directional effect of the leaky wave antenna. Like the dielectric leaky-wave antenna 1 according to the first exemplary embodiment, the dielectric leaky-wave antenna 1 according to the second exemplary embodiment does not only radiate in the y direction according to FIGS. 14 and 15. The leaky wave antenna 1 radiates just as strongly in the opposite direction. As described, this radiation is not desired in most applications and significantly reduces the antenna gain in the direction of use.

A higher gain of the leaky wave antenna 1 is therefore achieved as described by positioning reflection surfaces on the side of the first dielectric waveguide 5 facing away from the interference locations 15 or additionally on at least one longitudinal side of the first dielectric waveguide 5. The unwanted radiation is reflected by the reflective surfaces in the direction of use. The

Reflection surfaces should be positioned and shaped so that the reflected radiation overlaps the radiation in the direction of use in such a way that no deformation of the radiation characteristic occurs in the direction of use.

As a result of the described disturbance points 15 arranged on one side on the top 135 of the first dielectric waveguide 5, fluctuations in the radiation amplitude occur during the described pivoting process of the first directional lobe 25. This is due to the fact that the ferrite rods 45, 46 arranged on the underside 140 act according to FIGS. 14 and 15, depending on their direction of magnetization, as additional radiating sites. The fluctuations in the radiation amplitude mentioned can be considerably reduced if additional fault locations 15, 18 in the area of the ferrite rods 45, 46 on the underside 140 of the first dielectric waveguide 5, for example in the form of metal strips. The blind spots 15 on the underside 140 can of course also be designed accordingly as dielectric grooves.

The description of the leaky wave antenna 1 with reference to the first dielectric waveguide 5 can be applied to all other dielectric waveguides 6, 7, 8,..., 12 both for the first exemplary embodiment described and for the second exemplary embodiment described. The leaky wave antenna 1 can be constructed from a single dielectric waveguide described in the first exemplary embodiment or the second exemplary embodiment or from an antenna array with at least two such waveguides, the configuration as an antenna array 80 according to FIG. 3, FIG. 4, FIG. 17 and FIG. 19 with eight or four waveguides is only described as an example.

The areas of application of the dielectric leaky-wave antenna 1 according to the second exemplary embodiment, like the first exemplary embodiment, are antenna systems which have to be pivoted in their antenna characteristics in at least one plane. According to FIGS. 3 and 4, an antenna array 80 can also be realized for the second exemplary embodiment, as is exemplarily indicated in an implementation form in FIG. 17 and, in addition to the pivotable first directional lobe 25 in the direction of the waveguide plane according to the exemplary embodiment according to FIG. 3 5, 6, 7, ..., 12 also the second directional lobe 26 orthogonal to the plane of the waveguides 5, 6, 7, ..., 12 has, however, according to the embodiment of Figure 3 is not pivotable. Using the phase shifters according to FIG. 4, the second directional lobe 26 can also be pivoted as described.

Thus, the leaky wave antenna 1 according to the second exemplary embodiment also provides an antenna with an electronically pivotable antenna characteristic which can be constructed in a cost-effective and space-saving manner and can generally be used as an antenna system which is adaptive in its antenna characteristic. The leaky wave antenna 1 can be used, for example, in high-resolution, imaging radar systems. In general, the use of the leaky wave antenna 1 according to the first and the second exemplary embodiment is possible in all antenna systems in which a certain spatial area has to be scanned in two or three dimensions with or according to high-frequency signals.

Claims

Expectations

1. leakage wave antenna (1) with at least one dielectric waveguide (5, 6, 7, ..., 12) and interference points (15), each of which a part of the waveguide (5, 6, 7, ..., 12) is emitted or received in the form of an electromagnetic wave (20) guided electromagnetic field, the phase difference of the electromagnetic wave (20) between adjacent impurities (15) being approximately the same size, so that a directional antenna characteristic (25, 26) results, characterized in that the leaky wave antenna (1) means (30; 35, 36; 41, 42, 43, ..., 47) for changing the propagation constant of the waveguide (5, 6, 7, ..., 12) comprises, a change in the propagation constant resulting in a change in the wavelength of the electromagnetic wave (20, 6, 7,..., 12) propagating via the waveguide and thus a change in the phase difference resulting in a pivoting of the directional antenna pattern (25, 26) leads.

2. leaky wave antenna (1) according to claim 1, characterized in that the means (30; 35, 36; 41, 42, 43, ..., 47) for changing the propagation constant means (30; 35, 36) for changing the effective permittivity ε _eff for the electromagnetic wave (20) propagating via the waveguide (5, 6, 7, ..., 12).

3. leaky wave antenna (1) according to claim 2, characterized in that the means (30; 35, 36) for changing the effective permittivity ε _eff means (30) for changing the relative permittivity ε _{r of} the waveguide (5, 6, 7, ..., 12) by applying a voltage (U _sc ) to the waveguide (5, 6, 7, ..., 12).

4. leaky wave antenna (1) according to claim 3, characterized in that the waveguide (5, 6, 7, ..., 12) is at least partially built up in layers, the voltage (U _st .) Between the layers (50, 51st ) is introduced.

5. leaky wave antenna (1) according to any one of claims 2 to 4, characterized in that the means (30; 35, 36) for changing the effective permittivity ε _eff means (30) for changing the relative permittivity ε _r at least one laterally to the Waveguide (5, 6, 7, ..., 12) attached first dielectric rod (35, 36) through

Apply a voltage (U _sc ) to this dielectric rod (35, 36).

6. leaky wave antenna (1) according to claim 5, characterized in that the at least one laterally to the

Waveguide (5, 6, 7, ..., 12) attached first dielectric rod (35, 36) is built up in layers, the voltage (U _st ) being introduced between the layers (55, 56).

7. leaky wave antenna (1) according to one of claims 2 to 6, characterized in that on one of the defects (15) of the waveguide (5, 6, 7, ..., 12) opposite side of the waveguide (5, 6, 7th , ..., 12) another dielectric rod (40) with through

Applying a voltage (U _st ) variable relative permittivity ε _{r is} arranged to control the power distribution in the leaky wave antenna (1), with an increase in the relative permittivity ε _{r of} the second dielectric rod (40) the electromagnetic wave (20) runs more in the region of the waveguide (5, 6, 7, ..., 12) facing the second dielectric rod (40), so that less power is emitted at the defects (15).

8. leaky wave antenna (1) according to claim 7, characterized in that the further dielectric rod (40) is built up in layers, the voltage (U _st ) between the layers (60, 61) is introduced.

9. leakage wave antenna (1) according to claim 7 or 8, characterized in that the further dielectric rod (40) is divided into several separate sections, the relative permittivity ε _{r can be} changed individually to an individual

To implement power control for at least some of the fault points (15).

10. corner wave antenna (1) according to claim 1, characterized in that the means (30; 35, 36; 41, 42, 43,

..., 47) to change the propagation constant means (30; 41, 42, 43, ..., 47) to change the effective permeability μ _eff for which the waveguide (5, 6, 7, ..., 12) include propagating electromagnetic wave (20).

11. leaky wave antenna (1) according to claim 10, characterized in that the means (30; 41, 42, 43, ..., 47) for changing the effective permeability μ _eff in the region of impurities (15) of the waveguide (5, 6, 7, ..., 12) transverse to the waveguide (5, 6, 7, ..., 12) magnetized ferrite elements (41, 42, 43, ..., 47) and means (30) for adjusting the magnetization of these magnetizable ferrite elements (41, 42, 43, ..., 47), the size of the swivel angle (φ) for the swiveling of the directional antenna characteristic (25, 26) depends on the magnetization of the ferrite elements (41, 42, 43, ..., 47).

12. leaky wave antenna (1) according to claim 11, characterized in that the means (30) for adjusting the magnetization reverses the magnetization direction of the magnetizable ferrite elements (41, 42, 43, ..., 47).

13. leakage wave antenna (1) according to claim 11 or 12, characterized in that the means (30) for adjusting the magnetization, the ferrite elements (41, 42, 43, ..., 47) each between two magnetic saturation states (65, 70) switch.

14. leakage wave antenna (1) according to claim 13, characterized in that the ferrite elements (41, 42, 43, ..., 47) are divided into sub-elements (71, 72, 73, ..., 76), the different cross-sectional area have a magnet angle of the antenna characteristic (25, 26) which is dependent on the cross-sectional area.

15. leakage wave antenna (1) according to claim 11 or 12, characterized in that the means (30) for adjusting the magnetization of the ferrite elements (41, 42, 43, ..., 47) the magnetization of the ferrite elements (41, 42, 43 , ..., 47) continuously between two magnetic saturation states (65, 70).

16. leakage wave antenna (1) according to one of claims 11 to 15, characterized in that the ferrite elements (41, 42, 43, ..., 47) are annular and that the means (30) for adjusting the magnetization of Ferrite elements (41, 42, 43, ..., 47) each comprise a current-carrying conductor wound around the corresponding ferrite element, which induces a magnetic field in the corresponding ferrite element (41, 42, 43, ..., 47).

17. Leak wave antenna (1) according to one of claims 10 to 16, characterized in that the impurities (15) on opposite sides of the waveguide (5, 6, 7, ..., 12) are arranged.

18. Leaky wave antenna (1) according to one of the previous ones

Claims, characterized in that an antenna array (80) is formed from several waveguides (5, 6, 7, ..., 12) arranged in parallel and by a common one

Distribution network (85) is fed.

19. leaky wave antenna (1) according to claim 18, characterized in that at least a part of the waveguides (5, 6, 7, ..., 12) each have a phase shifter (91, 92,

93, ..., 98).

20. leakage wave antenna (1) according to claim 19, characterized in that the means (30; 35, 36; 41, 42, 43, -.-, 47) for changing the propagation constant of

The waveguide (5, 6, 7, ..., 12) in a region at one end of the respective waveguide (5, 6, 7, ..., 12), which faces the distribution network (85), separately control the propagation constant to a phase shift between the individual waveguides

(5, 6, 7, ..., 12).

21. leakage wave antenna (1) according to one of claims 18 to 20, insofar as they are related to one of claims 10 to 18, characterized in that in their magnetization Ferrite elements (41, 42, 43, ..., 47) of different waveguides (5, 6, 7, ..., 12) which are to be driven in the same way are combined and controlled together.

22. leakage wave antenna (1) according to claim 21, characterized in that in each case a plurality of identically controlled ferrite elements (41, 42, 43, ..., 47) in the region of mutually corresponding defects (15) of a plurality of parallel waveguides (5, 6, 7 , ..., 12) are combined to form a common ferrite ring.

23. Leaky wave antenna (1) according to one of the previous ones

Claims, characterized in that one or more reflection surfaces are arranged on at least one side of the at least one waveguide (5, 6, 7, ..., 12).

24. Leaky wave antenna (1) according to one of the previous ones

Claims, characterized in that below, on the side of the waveguide facing away from the defects (15)

(5, 6, 7, ..., 12) additional impurities are arranged.

25. leaky wave antenna (1) according to any one of the preceding claims, characterized in that at least some of the defects (15) are designed as dielectric grooves.

26. leakage wave antenna (1) according to any one of the preceding claims, characterized in that at least part of the impurities (15) are designed as metal strips.