GB2476727A

GB2476727A - Frequency scanning antenna with elements radiating different signal power

Info

Publication number: GB2476727A
Application number: GB1022046A
Authority: GB
Inventors: Thomas Focke; Joerg Hilsebecher; Oliver Lange; Reinhard Meschenmoser; Arne Zender; Thomas Schoeberl; Thomas Hansen; Joachim Selinger; Karl Schneider
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-12-29
Filing date: 2010-12-24
Publication date: 2011-07-06
Anticipated expiration: 2030-12-24
Also published as: GB2476727B; GB201022046D0

Abstract

An antenna, suitable for radiating a signal in a direction in space dependent on the frequency of the signal, comprises an antenna body with a dielectric material and signal line 200 located between two parallel conductive ground surfaces and a plurality of aperture antenna elements 300 arranged in a straight line in one of the conductive ground surfaces. The line of aperture antenna elements 300 are arranged above the signal line 200 and at least two of the antenna elements 300 differ from one another such that they radiate with different power. The central antenna elements 340 may be large whilst the antenna elements 300 get smaller the further they are from the central antenna elements 340. The radiated beam signal power distribution may be used to reduce the level of side lobes. The signal line 200 may be a serpentine waveguide or strip line conductor with structures compensating for the signal disturbances caused by the antenna elements. The antenna may include a segment of a cylindrical lens made of polyetherimide to focus and increase the gain of the antenna beam. Various antenna element arrangements are described which may be used to adjust the radiated beam from the antenna.

Description

S -t

ANTENNA

The present invention relates to an antenna.

Radar installations use antennae in order to radiate radar beams. Radar installations are known which scan a visual range by a focused radar beam. An antenna which radiates merely in a narrowly defined direction in space is needed for that purpose. In addition, this direction in space of the radiation must be able to change so that the visual range can be sequentially scanned. Antennae suitable for this purpose are also termed scanners.

Moreover, antenna are known in which the radiation direction depends on the frequency of the radiated radar beam. Such antennae are termed frequency scanners and are described in, for example, WO 95/20169 and DE 10 2007 056 910.8. Known frequency-scanning antennae are, however, complicated and costly to manufacture and offer only a sub-optimal directional characteristic or beam focusing.

The object of the present invention is therefore to provide an improved antenna.

According to the present invention there is provided an antenna comprising an antenna body with a plurality of first antenna elements which are arranged along a first straight line, wherein the antenna body comprises a first conductive ground surface and a second conductive ground surface, wherein the first and second ground surfaces are arranged substantially parallel to one another, wherein a dielectric is arranged between the first and second ground surfaces, wherein a signal line is arranged between the first and the second ground surfaces, wherein the first antenna elements are constructed as openings, which are arranged above the signal line, in the first ground surface, wherein the antenna is constructed to radiate a signal in a direction in space dependent on a frequency of the signal and wherein at least two of the first antenna elements then differ from one another in the manner that they radiate a different amount of power.

Advantageously, through this design of first antenna elements the antenna configuration of the antenna can be optimised, whereby a particularly favourable radiation characteristic can be achieved.

With particular preference the power radiated by the first antenna elements interferes so 4 4

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that a side lobe suppression of the radiated power in the far field is more than 25 dB.

Advantageously, the first antenna elements comprise an outer antenna eiement and a central antenna element, wherein the opening forming the outer antenna element has a first diameter and wherein the opening forming the second antenna element has a second diameter. In that case the first and second diameters differ. Advantageously, the antenna configuration can then be set by way of the hole size.

With particular preference the first antenna elements comprise a mean first antenna element, wherein the power radiated by a first antenna element is approximately proportional to the square of the cosine of the spacing, which is normalised to Tr12, of this first antenna element from the mean first antenna element. Advantageously, tests and computations have shown that a particularly favourable radiation characteristic of the antenna can be achieved with an antenna configuration of that kind.

The signal line preferably comprises at least one compensation structure, which is so constructed that compensation can be provided for disturbance of the signal line caused by reflection at the first antenna elements. The radiation characteristic of the antennae can thereby be improved.

In a preferred development the antenna comprises a lens having the form of a segment of a cylinder. In that case, a longitudinal axis of the lens is oriented parallelly to the first straight line. Moreover, the lens comprises a dielectric material. Advantageously, the beam radiated by the antenna can thus be focused in a direction perpendicular to the sweep direction of the antenna, whereby the gain of the antenna can be increased.

Advantageously, the lens comprises polyetherimide, which has proved particularly

suitable.

In one preferred embodiment the antenna comprises a plurality of second antenna elements arranged outside the first straight line. In that case, the second antenna elements are constructed as patch elements and at least two of the antenna elements are connected together by a microstrip conductor. Advantageously, the second antenna elements can then be used for detection of a reflected radar signal and thereby improve the resolution of the antenna in a direction perpendicular to the sweep direction thereof.

The second antenna elements can also be used for transmitting a radar signal.

The second antenna elements are preferably arranged in a row paraiiei to the first straight line. In that case, the second antenna elements are connected together by a microstrip conductor. This arrangement is particularly suitable for detection of the reflected signal, but can also be used for transmitting a radar signal.

In a further preferred embodiment the antenna comprises a second antenna body having a plurality of third antenna elements arranged along a second straight line. In that case the second straight line is oriented parallel to the first straight line. Moreover, a waveguide running between the third antenna elements is arranged in the second antenna body and the third antenna elements are constructed as openings extending between the waveguide and a surface of the second antenna body. Advantageously, either the second antenna body can be used for detection of a reflected radar signal, whereby the resolution of the antenna in a direction perpendicular to the sweep direction thereof is improved, or the signals radiated by the first and second antenna bodies can interfere in the manner that an improved focusing perpendicular to the sweep direction results.

In a further preferred development of the antenna at least one antenna slot is provided with a plurality of fifth antenna elements, wherein the antenna slot is oriented perpendicularly to the first straight line and is coupled with a first antenna element by way of a coupling structure. Advantageously, the antenna slot then provides focusing of the signal, which is radiated by the antenna, in a direction perpendicular to the sweep direction of the antenna, whereby the radiation characteristic of the antenna can be improved.

For preference the antenna slot is constructed as a microstrip conductor antenna, wherein the fifth antennae elements are constructed as patch elements. The antenna slot can then be produced simply and economically.

Advantageously, a substrate is provided between the antenna body and the antenna slot.

The substrate provides an electrical insulation of the antenna slot from the antenna body.

In an alternative form of embodiment the antenna slot is constructed as a waveguide and the fifth antenna elements are formed as openings therein. Such a waveguide advantageously produces focusing of the signal, which is radiated by the antenna, in a direction perpendicular to the sweep direction of the antenna.

Embodiments of the present invention will now be more particuiariy described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of an antenna body of a first antenna embodying the invention; Fig. 2 is a perspective view of the antenna body of Fig. 1 in opened state, showing an internally disposed waveguide; Fig. 3 is a schematic view of the waveguide; Fig. 4 is a further view of the waveguide, with antenna elements; Fig. 5 is a diagram showing the radiation characteristic of the antenna; Fig. 6 is a perspective illustration of the antenna, with the addition of a lens; Fig. 7 is a view of a second antenna, with additional antenna slots, embodying the invention; Fig. 8 is a view of a third antenna, with additional antenna slots, embodying the invention; Fig. 9 is a sectional view of the antenna of Fig. 8; Fig. 10 is a view of a fourth antenna, with additional antenna slots embodying the invention; Fig. 11 is a sectional view of the antenna of Fig. 10; Fig. 12 shows a view of an antenna embodying the invention; Fig. 13 is a view of an antenna embodying the invention, with additional antenna

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bodies; and Fig. 14 is a view of a waveguide, which is constructed as a strip conductor, in an antenna embodying the invention.

Figs. 1 and 2 show in perspective illustration an antenna body 105 of an antenna 100.

The antenna body 105 has an upper part 110 and a lower part 120. In the illustration of Fig. I of the upper part 110 and the lower part 120 of the antenna body 105 are connected together by screws. Fig. 2 shows upper part 110 and lower part 120 of the antenna body in an unconnected state. The upper part 110 and lower part 120 are each formed as a substantially flat block. The upper part 110 and the lower part 120 of the antenna body can be joined together in such a manner that a surface of the upper part 110 comes into contact with a surface of the lower part 120.

The surfaces, which can be joined together, of the upper part 110 and lower part 120 each have a meandering groove-like depression. When the upper 110 and lower part 120 are joined together, the groove-like depressions complement one another to form a waveguide extending in the interior of the antenna body 105. The waveguide 200 in that case runs between an entry 210 arranged at an edge of the antenna body 105 and an exit 220 disposed at the same edge of the antenna body 105. A high-frequency electromagnetic signal can be coupled into and coupled out of the waveguide 200 by way of the entry 210 and exit 220. The signal can have, for example, a frequency of 77 GHz. For horizontal sweep by the radar beam emitted by the antenna 100 the frequency can be varied by, for example, an amount of 2 GHz.

The upper part 110 of the antenna body 105 has a plurality of first antenna elements 300 arranged along a straight line. The first antenna elements are formed as openings running between an outer surface of the antenna body 105 and the waveguide 200 in the interior of the antenna body 105. The straight line along which the first antenna elements 300 are arranged extends parallel to the length direction of the meandering waveguide 200. In that case, each turn of the meandering waveguide 200 has an opening forming an antenna element 300. The antenna elements 300 are respectively arranged centrally between two successive turns of the waveguide 200. However, it is also possible to arrange the antenna elements 300 at different positions of the waveguide 200, for example, in the vicinity of or directly at the turns of the meandering course of the waveguide 200. There k.

can be provided, for example, 24 or 48 or another number of antenna elements 300. The direct spacing between two adjacent antenna elements 300 is selected in dependence on the frequency of the signal radiated into the waveguide 200 and cart approximately correspond with, for example, half the wavelength of the signal. Through the meandering shape of the waveguide 200 the length of the waveguide 200 between two adjacent antenna elements 300 is greater and can correspond with, for example, 5.5 times the wavelength of the signal.

The antenna body 105 consists of an electrically insulating material, which is coated with a conductive material. The electrically insulating material can be, for example, a plastics material, preferably polyetherimide or polybutyleneterephthalate. In this case, the antenna body 105 can be produced, by way of example, by an injection-moulding method.

Alternatively, the antenna body 105 can consist of a glass. In this case the antenna body can be produced by, for example, a stamping process. The antenna body 105 can also consist of a different insulating material. A coating of a conductive material is applied to the insulating material of the antenna body 105. This is necessary so that the waveguide is suitable for transmission of an electromagnetic wave. The conductive coating can consist of different coating combinations and materials. A coating with gold or aluminium, which is only a few microns thick, has proved particularly suitable. The coating can be applied by, for example, physical gas phase deposition or by means of an electroplating method.

The waveguide 200 can additionally be filled with a medium, which is transparent to radar radiation, for protection of the conductive coating against corrosion. Low-reaction gases, polytetrafluoroethylene, various foams or also a vacuum are, for example, suitable for this purpose. In one possibility only the waveguide 200 is filled with the medium, for which purpose the antenna elements 300, the entry 210 and the exit 220 have to be sealed by a material transparent to radar radiation. Alternatively, the entire antenna body 105 can also be disposed in the desired medium.

Fig. 3 is a further schematic illustration of the waveguide 200 in the interior of the antenna body 105 of the antenna 100. The waveguide 200 consists of a plurality of sections which are oriented parallelly to the x axis and which are connected together in meandering form by turns in such a manner that the waveguide 200 extends as a whole in y direction. The first antenna elements 300 are arranged along the first straight line oriented parallelly to 4, the y axis. The first antenna elements 300 constructed as openings towards the waveguide 200 represent a disturbance of the waveguide 200 and impair the wave-guiding characteristics thereof. In order to provide compensation for the disturbance of the waveguide 200 caused by the first antenna elements 300 the waveguide 200 has a plurality of compensation structures 230. The structures 230 are formed as narrowings of the waveguide 200 in the vicinity of the openings forming the first antenna elements 300.

The structures 230 are so dimensioned that they provide compensation for the effect of the first antenna elements 300 on the waveguide 200. The structures 230 can also be arranged at a different location, for example at a greater spacing from the first antenna elements. However, it has proved particularly advantageous to provide the structures 230 as close as possible to the first antenna elements 300. The structures 230 improve the radiation characteristics of the antenna 100.

Fig. 4 is a further view of the upper part 110 of the antenna body 105 and the waveguide arranged therein. Fig. 4 shows that the openings forming the first antenna elements 300 have different diameters. In that case, the openings do not have to be formed to be circular, but can also have a different shape, for example a rectangular shape, In this connection, the term "diameter" denotes the size of the opening regardless of the exact form of the opening, thus a diagonal or transverse dimension of the opening. An outer antenna element 330 closest to the entry 210 of the waveguide 200 has a first diameter 310. A central antenna element 340 in the middle of the waveguide 200 has a second diameter 320. The second diameter 320 is larger than the first diameter 310. The first antenna elements 300 arranged between the central antenna element 340 and the outer antenna element 330 have diameters lying between the first diameter 310 and the second diameter 320. In that case the diameter of the first antenna elements 300 increases in direction towards the centre of the waveguide 200. This correspondingly applies to the first antenna elements 300 between the exit 220 of the waveguide 200 and the centre of the waveguide 200.

The size of the holes forming the first antenna elements 300 predetermines the power radiated by the first antenna elements 300. The distribution of the powers radiated by the different first antenna elements 300 is termed antenna configuration. The design of the antenna configuration has a critical influence on the directional characteristic of the antenna 100. In the case of a constant configuration in which all first antenna elements 300 radiate approximately the same power, a directional characteristic with only small side " 8 lobe suppression results. Through an improved antenna configuration the side lobe suppression can, however, be similarly improved. The directional characteristic of the antenna 100 in the far field results from a Fourier transformation of the antenna configuration. A suitable antenna configuration can thus be calculated from the desired far field of the antenna 100. An antenna configuration in which the radiated power of each first antenna element 300 is approximately proportional to the square of the cosine of the spacing, which is normalised to rr/2, of the respective first antenna element 300 from the central antenna element 340 has proved particularly favourable. The normalised spacing of the outer antenna element 330 from the central antenna element 340 corresponds with a value of n12. The power radiated by the outer antenna eiement 330 is proportional to the square of the cosine of n-12, thus equal to zero. Antenna elements 300 located between the outer antenna element 330 and the central antenna element 340 correspondingly have a normalised spacing from the central antenna element 340 of less than rr12. The outermost antenna elements 330, which radiate a power of zero, can obviously also be eliminated. However, other antenna configurations are also possible.

Overall, a side lobe suppression of the radiated power in the far field of the antenna 100 of more than 25 dB can be achieved.

The exact diameter of the openings forming the first antenna elements 300 results from the desired antenna configuration and a correction taking into consideration the fact that the high-frequency electromagnetic signal is fed to the waveguide 200 at one end via the entry 210. The antenna elements 300 further from the entry 210 therefore have to have a greater diameter than antenna elements 300 disposed near the entry 210.

The side lobe suppression of the signal radiated by the antenna can thus, as stated, be optimised by a suitable antenna configuration of the first antenna elements 300. Fig. 5 is a diagram showing a comparison of the directional characteristics of an antenna 100 with the described compensation structures 230 and an optimised antenna configuration of the first antenna elements 300 in comparison with the directional characteristic of an antenna without the described optimisations. In that case, the radiation angle of the antenna is recorded on the horizontal axis and a normalised antenna gain is recorded on the vertical axis. The first directional characteristic 400 of the non-optimised antenna has a first side lobe suppression 410. A second directional characteristic 420 of the optimised antenna has a second side lobe suppression 430. It can be seen that the second side lobe suppression 430 of the optimised antenna 100 is better than the first side lobe suppression 410 of the non-optimised antenna.

Fig. 6 shows a further perspective view of the antenna 100 with the antenna body 105.

The first antenna elements 300 of the antenna 100 are arranged along the first straight line which is oriented parallelly to the y axis. The radiation angle of the antenna 100 in the y-z plane changes through variation of the frequency of the high-frequency signal coupled into the waveguide 200. However, in x direction the antenna 100 radiates in a wide angular range. A lens 500 is therefore arranged in front of the antenna body 105 in Fig. 6. The lens 500 has the form of a segment of the cylinder, the longitudinal or cylinder axis of which is oriented parallelly to the y axis. The lens 500 focuses the beam, which is radiated by the antenna 100, in x direction and thereby increases the gain of the antenna 100. The signal radiated by the antenna 100 is not changed by the lens 500 in y direction. The lens can be made of different materials. Polyetherimide has proved particularly suitable. The antenna 500 can increase the antenna gain of the antenna 100 by up to 7 dB.

Fig. 7 shows a view of an antenna 3100 according to a further embodiment. The antenna 3100 again comprises first antenna elements 300, which are arranged along the first straight line. In addition, the antenna 3100 comprises further antenna slots which are oriented perpendicularly to the first straight line. A first antenna slot 3150, a second antenna slot 3151, a third antenna slot 3152 and a fourth antenna slot 3153 are illustrated in Fig. 7. The antenna 3100 preferably has many antenna slots as first antenna elements.

Each of the antenna slots has a plurality of fifth antenna elements 3300, which are constructed as patch elements. In the embodiment of Fig. 7 each antenna slot has six antenna elements 1300. The antenna elements 3300 of an antenna slot are respectively connected together by way of a microstrip conductor. The microstrip conductor and the antenna elements 3300 consist of an electrically conductive material, for example of a metal. In addition, each antenna slot 3150 to 3153 has a coupling web 3200, which is similarly constructed as a microstrip conductor and is connected with the microstrip conductor connecting the antenna elements 3300. The coupling web 3200 of each antenna slot is respectively arranged above a first antenna element 300 of the antenna 3100 and forms together with this antenna element 300 a first coupling structure 3700.

The power radiated by the respective first antenna element 300 is coupled by way of the first coupling structure 3700 into the antenna slot coupled by way of the respective first antenna element 300. Since the antenna slots are oriented perpendicularly to the first straight line, the antenna slots produce a focusing of the signal, which is radiated by the antenna 3100, perpendicularly to the sweep plane of the antenna. The coupling structures 3700 can, as illustrated in Fig. 7, be arranged in the centre of the respective antenna slots.

Alternatively, however, the coupling structures 3700 can also be provided at the edges or at any other positions of the antenna slots.

Fig. 8 shows a view of an antenna 4100 according to a further embodiment. The antenna 4100 also has a plurality of antenna slots which are arranged above the first antenna elements 300 and oriented perpendicularly to the first straight line. By contrast to the antenna 3100 illustrated in Fig. 7, the antenna slots of the antenna 4100 do not, however, have a coupling web 3200. Instead, one of the antenna elements 3100 of each antenna slot is arranged above a respective antenna element 300 and forms therewith the first coupling structure 3700. In addition, the power radiated by the respective antenna element 300 is thereby coupled into the antenna gap arranged above the respective antenna element 300, whereby focusing of the signal, which is radiated by the antenna 4100, perpendicularly to the sweep direction results. The positions of the coupling structures 3700 at the antenna slots can again be selected as desired.

Fig. 9 shows a section through one of the first coupling structures 3700 of the antennae 3100 of Fig. 7. It can be seen that a substrate 3710 is arranged between the coupling web 3200 of the antenna slot 3150 and the first antenna element 300. The substrate 3710 consists of an electrically insulating material and electrically insulates the antenna slot 3150 from the antenna body 3105.

Fig. 10 shows a view of an antenna 5100 according to a further embodiment. The antenna 5100 again has a plurality of first antenna elements 300 arranged along a first straight line.

Moreover, the antenna 5100 has a plurality of antenna slots 3160, 3161, 3162, 3163, which are respectively oriented perpendicularly to the first straight line and each arranged above one of the first antenna elements 300. Each of the antenna slots 3160 to 3163 is constructed as a waveguide antenna with a plurality of sixth antenna elements 3310. In a central section of each of these antenna slots the respective slot is coupled by means of a second coupling structure 3800 to the respective first antenna element 300 disposed thereunder. The power radiated by the first antenna elements 300 is thereby coupled into the antenna slots 3160 to 3163, whereby focusing of the signal radiated by the antenna 5100 perpendicularly to the sweep direction of the antenna 5100 results.

Fig. 11 shows, in section through the antenna 5100 of Fig. 10, one of the second coupling structures 3800. The waveguide of the antenna slot 3160 is arranged perpendicuiariy above the waveguide 200 of the antenna 5100. The waveguide of the antenna 5100 is connected with the waveguide of the antenna slot 3160 by one of the first antenna elements 300. A sixth antenna element 3310 of the antenna slot 3160 is arranged above the waveguide and the first antenna element 300. The sixth antenna element 3310 can be formed as an opening or be closed by, for example, a dielectric material.

The antennae 3100, 4100, 5100 of Figs. 7 to 11 have the advantage that the antenna slots produce focusing the signal, which is radiated by the antenna perpendicularly to the respective sweep direction without a lens being required. The constructional space required for the antenna is thereby reduced.

Fig. 12 shows a view of an antenna 1100 according to a further embodiment. The antenna 1100 again comprises a plurality of first antenna elements 300 arranged along a first straight line oriented parallel to the y axis. In addition, the antenna 1100 comprises a plurality of second antenna elements 600 which are arranged in x direction near the first antenna elements 300. The second antenna elements 600 are arranged in rows oriented parallelly to the first straight line. Fig. 12 shows, by way of example, a first row 610 and a second row 620. However, further rows with further second antenna elements 600 can also be present. The second antenna elements 600 are constructed as patch elements.

The second antenna elements 600 of each row 610, 620 are connected together by way of a microstrip conductor. The microstrip conductor is not illustrated in Figure 12. Each row 610, 620 thus forms an own patch antenna. Each row 610, 620 can be connected with an own electronic evaluating means. The rows 610, 620 can be used for detection of a reflected radar signal. Since the rows are arranged adjacent to one another in x direction, the rows allow the reflected radar signal to be resolved, independently of angle, in x direction, thus perpendicularly to the sweep direction of the antenna 1100. The antenna 1100 can scan the space lying in front of the antenna 1100, thus in the y-z plane, by sweeping of the emitted radar beam and resolve the reflected radar signal in dependence on angle in the x-z plane. The antenna 1100 thereby achieves a good angle resolution not only vertically, but also horizontally. Alternatively, the second antenna element 600 could also be used for transmitting.

Fig. 13 shows a view of an antenna 1200 according to a further embodiment. The antenna comprises the antenna body 105, which was already explained with reference to Fig. 1, with the first antenna elements 300. In addition, the antenna 2100 comprises a second antenna body 2105 and a third antenna body 2106. The antenna can also comprise further antenna bodies. The second antenna body 2105 and the third antenna body 2106 correspond in their construction with the first antenna body 105. Thus, the second antenna body 2105 comprises third antenna elements 2300 and the third antenna body 2106 comprises fourth antenna elements 2305. The first antenna elements 300, the third antenna elements 2300 and the fourth antenna elements 2305 are respectively oriented parallelly to the y axis. In x direction, the antenna elements of the different antenna bodies 105, 2105, 2106 can be arranged either directly one above the other or laterally opposite one another.

The antenna 2100 can be used in different ways. In one possibility, the individual antenna bodies 105, 2105, 2106 are supplied by a common high-frequency source so that the individual antenna elements 105, 2105, 2106 radiate synchronously with one another. In this case the part beams emitted by the individual antenna bodies 105, 2105, 2106 interfere with one another, whereby focusing of the radar beam, which is emitted by the antenna 2100, in the y-z plane results. The function of the antenna 2100 then corresponds with that of the antennae 3100, 4100, 5100 of Figs. 7,8 and 10.

A second possibility of use of the antenna 1200 consists in using the first antenna body merely for transmitting radar beams and detecting the reflected radar signal by means of the second antenna body 2105 and the third antenna body 2106. The antenna 2100 then achieves an angular resolution perpendicularly to the sweep direction of the antenna 2100. This corresponds with the function of the antenna 1100 of Fig. 12.

The antennae of the previously described forms of embodiment each employ a waveguide having openings forming the first antenna elements 300. However, a strip conductor can also be used instead of the antenna body 105 and the waveguide 200. Fig. 14 shows in schematic sectional illustration a suitable strip conductor 700. The strip conductor 700 has a first ground surface 720 and a second ground surface 730. The first ground surface 720 and the second ground surface 730 consist of an electrically conductive material, for example of a metal. The first surface 720 and the second surface 730 can be electrically short-circuited. The two surfaces 720, 730 respectively extend in a plane and are arranged substantially parallel to one another. A dielectric 740 is arranged between the first surface 720 and the second surface 730. The dielectric preferably has a low relative ...4 1.... .,,.-.....,-.i.-. 41..... -..,.4._:... ...._.... I....-. ...I. 4._.4......fl.._...-.41....I.......,.......-., IJII'...,tj I'.... I....)I ILI IL. I UI AC1I ti i uiiii ii... .,cii t ij..iUiyLLi cilluol uu iyuu i UI ci uOcii like material.

A signal line 710 is embedded in the dielectric 740. The signal line 710 consists of an electrically conductive material, for example a metal. The signal line extends substantially along a direction. The signal line 710 does not necessarily have to be centred in the middle between the first ground surface 720 and the second ground surface 730. In addition, a different dielectric can be provided between signal line 710 and first surface 720 than between signal line 710 and second surface 730. The signal line 710 and the surfaces 720, 730 can together transmit a high-frequency electromagnetic signal.

The strip conductor 700 can replace the antenna body 105 with the waveguide 200 or serve as an alternative antenna body. In this case the first ground element 720 and/or the second ground element 730 has or have one or more openings serving as antenna elements. The thus-formed antenna elements correspond with the first antenna elements 300 of the antenna 100 of Fig. 1. The signal line 710 can run in meander form like the waveguide 200 or rectilinearly between the openings, which form the antenna elements, in the first ground element 720 and/or the second ground element 730.

The developments described with reference to Figs. 3 to 13 can be combined with an antenna based on the strip conductor 700. Thus, the openings, which form the antenna elements, in the first ground element 720 and/or the second ground element 730 can have different diameters in order to optimise the antenna configuration as described with reference to Figs. 4 and 5. The signal line 710 can have compensation structures as in Fig. 3, which compensate for disturbances caused by reflection at the antenna elements.

The cylinder lens 500 can similarly be combined with the strip conductor 700. Additional antenna slots can also be provided on a surface of the strip conductor.