Antenna device and method for emitting electromagnetic waves using the antenna device

Abstract

An antenna device (1) for emitting electromagnetic waves has a waveguide (2), which in turn has two plates (3) made of an electrically conductive material and arranged parallel to one another, between which a dielectric material is arranged. The antenna device (1) has a feed-in device (4), with which electromagnetic waves can be coupled into the waveguide (2), which then propagate along the waveguide (2) and are emitted at an edge (5) of the waveguide (2) at a distance from the feed-in device (4). According to the invention, using a control device of the antenna device (1), the dielectric material can be influenced in such a way that a first region (9) having a first permittivity and at least one second region (10) having a second permittivity are formed, such that the electromagnetic waves coupled into the waveguide (2) propagate preferably through the first region (9) and are emitted in this preferred propagation direction (11). The waveguide (2) can be in the shape of a circle segment and the feed-in device (4) can feed-in the electromagnetic wave in the centre of the circle. The dielectric material is a fluid having an anisotropic permittivity. The control device can have multiple respective electrodes (12), arranged on the plates (3) of the waveguide (2) and insulated in relation to same, between which an electric field can be generated.

Claims

1. An antenna apparatus (1) for emitting electromagnetic waves, comprising: a waveguide (2) that comprises two plates (3) arranged in parallel to one another of an electrically conductive material, between which a dielectric material is arranged; and a feed apparatus (4) by means of which electromagnetic waves can be coupled into the waveguide (2), which waves then propagate along the waveguide (2) and are emitted at an edge (5) of the waveguide (2) that is remote from the feed apparatus (4), wherein the dielectric material can be influenced, by a controller of the antenna apparatus (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, such that the electromagnetic waves coupled into the waveguide (2) preferably propagate through the at least one first region (9) and are emitted in said preferred propagation direction (11).

2. The antenna apparatus (1) according to claim 1, wherein the waveguide (2) is shaped in the manner of a circular sector and the feed apparatus (4) feeds in the electromagnetic wave in the center of the circle, and wherein the at least one first region (9) and the at least one second region (10) each form smaller circular sectors, within the waveguide, proceeding (2) from the center of the circle.

3. The antenna apparatus (1) according to claim 1, wherein the waveguide (2) comprises an outer peripheral edge that extends along a plurality of mutually adjoining chords, and the feed apparatus (4) feeds the electromagnetic wave into the center of the circle, and wherein edges of the at least one first region (9) and of the at least one second region (10) that proceed from the center of the circle each extend, in a circumferential circle, through the points of intersection of a chord assigned to the first and second region (9, 10), respectively.

4. The antenna apparatus (1) according to claim 1, wherein the dielectric material can be influenced, by the controller of the antenna apparatus (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. The antenna apparatus (1) according to claim 4, wherein the dielectric material of the at least one first region (9) is a dielectric solid, the shape of which corresponds to the first region (9), and the orientation of which relative to the feed apparatus (4) can be changed.

6. The antenna apparatus (1) according to claim 5, wherein the dielectric material comprises a dielectric solid, in particular barium strontium titanate.

7. The antenna apparatus (1) according to claim 1, wherein the dielectric material is a fluid having an anisotropic permittivity.

8. The antenna apparatus (1) according to claim 7, wherein the controller in each case comprises a plurality of electrodes (12) that are arranged on the plates (3) of the waveguide (2) and are isolated therefrom, between which an electric 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. The antenna apparatus (1) according to claim 8, wherein each electrode (12) is designed in the form of a strip or a narrow circular sector, and extends from the feed apparatus (4) to a remote edge of the associated plate (3) of the waveguide (2).

10. The antenna apparatus (1) according to claim 2, wherein each electrode (12) comprises a regularly or irregularly curved course along the edges thereof, and/or has a regularly or irregularly three-dimensionally structured surface.

11. The antenna apparatus (1) according to claim 1, wherein the two plates (3) are mutually spaced, in an edge region (5) remote from the feed apparatus (4), by a distance that increases as the distance from the feed apparatus (4) increases.

12. The antenna apparatus (1) according to claim 1, wherein edge regions (5) of the two plates (3) are each arranged, relative to antenna apparatus waveguide plane of the parallel regions of the plates (3) of the waveguide (2), at a specified angle, such that the electromagnetic waves are emitted at angle of between 0° and 90° relative to the waveguide plane.

13. The antenna apparatus (1) according to claim 1, wherein the antenna apparatus (1) comprises a plurality of waveguides (2) that are stacked on top of one another and into which electromagnetic waves can be coupled via a common feed apparatus (4) or via a plurality of separate feed apparatuses (4) that are each assigned to a waveguide (2).

14. A method for emitting electromagnetic waves using an antenna apparatus (1) according to claim 1, wherein at least one first region (9) having a first permittivity and at least one second region (10) having a second permittivity is formed using the controller, such that the electromagnetic waves coupled into the waveguide (2) preferably propagate through the at least one first region (9) and are emitted in said preferred propagation direction (11).

15. The method according to claim 14, wherein the at least one first region (9) is formed as a circular sector or a triangle and the orientation of the circular sector or triangle relative to the feed apparatus (4) is adjusted depending on a specified emission direction.

16. The method according to claim 14, wherein the at least one first region (9) is formed as a circular sector or a triangle and the angular range covered by the circular sector or triangle is adjusted depending on a specified directional focusing.

17. The method according to claim 14, wherein a plurality of antenna apparatuses are arranged so as to be mutually spaced and are operated in a synchronized manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of an antenna apparatus.

(2) FIG. 2 is a sectional view through the antenna apparatus shown in FIG. 1, along the line II-II in FIG. 1.

(3) FIG. 3 is a schematic illustration of the propagation of electromagnetic waves that are coupled into a waveguide of the antenna apparatus via the feed apparatus, and propagate, in the waveguide, along a first region having a first permittivity.

(4) FIG. 4 is a graphical depiction of radiation characteristics of emitted electromagnetic waves that were generated using a prototype of the antenna apparatus shown in FIGS. 1 and 2, emitted in various preferred propagation directions, and measured.

(5) FIG. 5 is a schematic plan view of an antenna apparatus comprising an electrode assembly that is attached to a plate of the waveguide and is intended for influencing a dielectric fluid arranged between the two plates of the waveguide.

(6) FIG. 6 is a schematic view of a differently designed antenna apparatus.

(7) FIG. 7 is a schematic view of an antenna apparatus that is again designed differently.

(8) FIG. 8 is a schematic view according to FIG. 2, wherein the electromagnetic waves propagate, in the waveguide in two different preferred propagation directions, along two first regions having a first permittivity.

(9) FIG. 9 is a graphical depiction of a radiation characteristic of the electromagnetic waves emitted in two preferred propagation directions by means of an antenna apparatus shown in FIG. 8.

(10) FIG. 10 is a schematic side view of an electrode comprising a crenelated-running edge on both sides.

(11) FIG. 11 is a schematic side view of an electrode comprising an irregularly undulating peripheral edge on both sides.

DETAILED DESCRIPTION

(12) FIGS. 1 and 2 are a schematic side view and a schematic cross section, respectively, of an embodiment, by way of example, of an antenna apparatus 1. The antenna apparatus 1 comprises a waveguide 2 that comprises two plates 3 arranged in parallel to one another and of a suitable electrically conductive material. The two plates 3 are each formed semi-circular. A feed apparatus 4 is arranged in the region of the center of the circle of the semi-circular plates 3, by means of which feed apparatus electromagnetic waves can be coupled into the waveguide 2 in order to then propagate along the waveguide 2, until the electromagnetic waves are emitted into free space, at an edge 5 of the waveguide 2 that is spaced from the feed apparatus 4.

(13) A fluid of a suitable liquid crystal material is arranged in an inner semi-circular intermediate space 6. The fluid is confined, towards the edge 5, by a semi-circular sealing ring 7 and is 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 semi-circular aperture slot 8, the slot width of which increases continuously as the distance from the center of the circle increases. The shape of the plates 3 in the region of the aperture slot 8 at the edge 5 corresponds to the shape of a horn radiator, and is intended to facilitate the transition of the electromagnetic wave from the waveguide 2 into free space.

(14) A controller (not shown in FIGS. 1 and 2) of the antenna apparatus 1 influences the fluid in the intermediate space 6 and creates a first region 9 having a first, high permittivity, which is delimited on both sides by a second region 10 in each case, in which second region the fluid has a second permittivity that is lower than the first permittivity. The electromagnetic waves that are coupled in from the feed apparatus 4 preferably propagate through the first region 9, having the higher permittivity, such that the electromagnetic waves preferably propagate and are emitted in a propagation direction that is specified by the orientation of the first region 9.

(15) The first region 9 and the two second regions 10 are each formed as a circular sector and together cover the associated semi-circular circular shape of the waveguide 2.

(16) FIG. 3 shows, by way of example, a simulated distribution of the electric field of the electromagnetic waves that are coupled into the waveguide 2. It can be clearly seen that the electromagnetic waves that are coupled in move almost exclusively through the first region 9, having the higher permittivity, and propagate and are emitted by the antenna apparatus 1 in a propagation direction 11 that is specified by the arrangement of the first region 9. Only a small portion of the electromagnetic waves propagates in the second region 10 and leaves the antenna apparatus 1 in a direction that differs from the preferred propagation direction 11.

(17) FIG. 4 shows radiation characteristics, generated and measured using a prototype of the antenna apparatus 1 shown in FIGS. 1 and 2, for the emission of the electromagnetic waves, wherein three different preferred propagation directions have been specified. It can clearly be seen that the maximum radiated power is in each case emitted in the specified propagation direction φ, specified so as to be 0°, 20° and 70° in the case of the measurements shown in FIG. 4. The reference system for the angle φ of the specified propagation direction is shown in FIG. 1.

(18) FIG. 5 schematically shows an arrangement of a number of electrodes 12 on a plate 3 of the waveguide 2. The individual electrodes 12 are in the shape of a circular sector in each case, and are arranged in a fan-like manner over the entire 180° angular range of the waveguide 2. A comparable electrode configuration is also arranged on the opposite plate 3. Using the controller (not shown), it is then possible to generate an electrical potential difference or an electric field between mutually associated electrodes 12 that are arranged on the two plates 3, which electrical potential difference or electric field acts on the dielectric fluid in the intermediate space between the two plates 3 in order, for example, to change and specify an orientation of individual liquid crystal molecules of the dielectric fluid and, associated therewith, the permittivity, in the intermediate space 6 covered by the electrodes 12.

(19) The electrodes 12 which are arranged side-by-side and to which a consistent electrical potential is applied, form the first region 9 which specifies the preferred propagation direction. The number of electrodes 12 which are assigned to the first region and to which a voltage is applied accordingly can specify a width of the first region 9 or an angular range that is covered by the first region 9. The more electrodes 12 are assigned to the first region 9 and to which voltage is applied accordingly, the wider the first region 9 is. It is possible, in principle, that for example 180 or 360 electrodes 12 may be arranged in the 180° angular range of the semi-circular waveguide 2, such that a correspondingly precise specification of the first region 9, and thus a precise adjustable and specifiable preferred propagation direction can be specified.

(20) FIG. 6 shows an embodiment, by way of example, for an antenna apparatus 1, by means of which only three different preferred propagation directions can be specified. The edge 5 of the waveguide 2 is formed by three chords that are adjacent to one another and also cover an angular range of 180°. The intermediate space 6 between the two plates 3 is divided into three regions 14 by three triangular electrodes 12. Each of said three regions 14 can be configured as the first region 9 for the preferred propagation direction or as the second region 10, by corresponding control of the electrodes 12 using the controller, in order for it to be possible to electively specify the preferred propagation direction for the antenna apparatus 1.

(21) FIG. 7 also shows an antenna apparatus 1, merely schematically and by way of example, comprising a circular waveguide 2. The electromagnetic waves are coupled in via a feed apparatus 4 arranged in the center of the circle, which apparatus is arranged on an outer face 13 of a plate 3 of the waveguide 2 and couples electromagnetic waves from the outside into the intermediate space 6 between the two plates 3. The electromagnetic waves that are coupled into the center of the circle can propagate in any desired direction, in the 360° angular range covered by the waveguide 2. The preferred propagation direction for the electromagnetic waves emitted by said antenna apparatus 1 can be specified by means of a suitable electrode configuration.

(22) FIGS. 8 and 9 are schematic views of an antenna apparatus 1 that is designed differently from FIG. 1 to 7, and the radiation characteristic thereof. Two first regions 9 are formed between the two plates 3 of a semi-circular waveguide 2, which regions are oriented at an anticlockwise angle φ′ or at a clockwise angle φ″ relative to a propagation direction that is directed centrally upwards in FIGS. 8 and 9. This generates an emission of electromagnetic waves having a radiation characteristic that is shown schematically in FIG. 9 and that clearly comprises two main emission directions.

(23) FIGS. 10 and 11 are schematic views of two different embodiments, by way of example, for an electrode 12. The electrode 12 shown in a side view in FIG. 10 comprises a number of crenelated projections 15 along the edges thereof, on an end face that faces the observer, such that both edges have a crenelated curved course. The individual crenelated projections 15 are uniform and are arranged in a regular manner. The electrode 12 which is also shown in FIG. 11 in a side view comparable to FIG. 10 has an undulating curved course 16 along the edges thereof, on the end face that faces the observer. The undulating curved course comprises individual undulating shapes which are non-uniform but are arranged in a substantially regular manner along the edges. The crenelated projections 15 and the individual undulating shapes could also be irregularly distributed along the edges. It is also possible for an outer face of the electrodes 12 that is arranged at the top and bottom in the end views in FIGS. 10 and 11 to have a correspondingly three-dimensionally structured surface. The non-straight edges, and optionally the three-dimensionally structured surfaces of the electrodes 12 can reduce or even entirely prevent an interfering influence of the electromagnetic field generated between the electrodes 12, by means of which field the first regions 9 and second regions 10 are created and specified, on the emission of the electromagnetic waves that are fed into the antenna apparatus 1 and emitted from the antenna apparatus 1.

(24) An antenna apparatus 1 provides significant advantages when used for various communications services and communications devices, and for example also when used in sensor technology. The antenna apparatus 1 allows for electrically controllable beam scanning without using an array antenna, having the disadvantages associated therewith. The losses, generally arising in the case of conventional array antennas, in a distribution network and in the individual phase shifters, can be prevented. The antenna apparatus 1 can be produced by means of comparatively simple manufacturing technologies, and is suitable in particular for emitting radio-frequency electromagnetic waves having a frequency of for example several gigahertz and more.