EP0848862B1 - Antenna array - Google Patents

Description

The invention relates to an antenna array for simultaneous Receive or for the simultaneous emission of electromagnetic Waves with two linear orthogonal ones Polarizations according to the preamble of claim 1.

Dual polarized antenna arrays, i.e. radiator arrangements, which dipoles, slots or planar radiator elements for simultaneous reception or simultaneous emission electromagnetic waves with two orthogonal linear Polarizations that are separate and separate from each other decoupled outputs are sufficient known. Such radiator arrangements can, for example of several elements in the form of dipoles, Slits or planar emitter elements exist as they do for example from EP 0 685 900 A1 or from the prior publication "Antennas", second part, by Adolf Heilmann, Bibliographical Institute Mannheim / Vienna / Zurich, 1970 University pocket book publisher, pages 47 to 50, known are. This applies to omnidirectional spotlights, for example with horizontal polarization the shapes of a dipole square or a dipole cross known, which is a coupling between the two systems offset by 90 ° exhibit.

To increase the directivity, such are below also referred to as radiator modules usually in front of a reflective surface, the so-called Reflector, arranged, with planar antennas simultaneously a metallic layer of the substrate as a reflector can act.

To increase the antenna gain, it is possible to use several these radiator modules to antenna fields, so-called arrays, interconnect. It is per sending and receiving station not uncommon, ten or more radiator modules interconnect to an array. The spotlight modules can be arranged side by side or one below the other. The direction in which the emitter modules are straight or inclined should be arranged next to or below each other be referred to as the alignment of the antenna array.

It has now proven to be disadvantageous that when interconnecting the result of several radiator modules Decoupling the arrays between the interconnected Radiator modules of both polarizations significantly worse fails than that of the radiator module itself. These disadvantage Effects occur especially when the alignment of the antenna array with one of the two Polarization planes coincide. Mainly kicks this case with antenna arrays, which are constructed in this way are that the radiator modules one above the other in the vertical direction are arranged, the radiator modules so aligned are that they have linear polarizations with a Receive angles of + 45 ° and -45 ° related to the vertical or blast. Such antenna arrays with from orientation deviating from the polarization plane hereinafter also referred to as X-polarized arrays.

With such arrays, it should be noted that i.a. by the mismatch of alignment of the array and the polarization planes as well as the oblique angle Position of the polarization planes to the reflector the neighboring ones Couple modules relatively strongly. As decoupling values of, for example, not sufficiently felt 20 to 25 dB are not uncommon.

Vertical polarization is preferred in the field of mobile communications is used, this antenna type offers dual polarized antennas with horizontal and vertical Polarization has the advantage of being on both polarizations can be sent to the mobile station.

Antenna arrays have already been proposed, which to improve the decoupling between the individual Emitters, i.e. the radiator modules, partitions provide, that is perpendicular to the direction of attachment or connection or line between two neighboring ones Radiator modules are aligned. Attempts have now reveal that such a construction in X-polarized Arrays by a polarization rotation to be determined usually even worsening Decoupling leads, especially with broadband antennas.

Finally, it is also known that when stacked vertically arranged single radiators with horizontal polarization horizontally arranged bars an improvement cause the decoupling between the individual radiators. However, this improvement in decoupling only affects Emitter of the same polarization and leads to X-polarized Arrays (where, for example, the vertical Alignment of the arrays, as mentioned, not with the linear ones Polarizations of + 45 ° and -45 °, for example) mostly no improvement in the decoupling between the different polarized feeding systems.

A corresponding to the antennas explained above Antenna array is also, for example, from US 3,541,559 known. The antenna array spans several in an antenna array, i.e. in several horizontal Radiator modules arranged in rows and vertical columns, being between two vertical and two horizontal radiator modules arranged side by side rod-shaped reflector element after. Kind of a parasitic Reflector is arranged. This rod-shaped parasitic Reflector element is transverse to the two adjacent Aligned connecting line connecting radiator modules. These parasitic reflector elements are used for radiation shaping, that even when using a single one Emitter module is effective.

The object of the present invention is therefore a To create X-polarized antenna array, which is preferred broadband a high decoupling between the resulting Has feed systems for both polarizations.

The task is according to the invention in accordance with the claim 1 specified features solved. Advantageous configurations the invention are specified in the subclaims.

It can be described as quite surprising that with the solution according to the invention compared to the state technology significantly improve the desired decoupling each of the adjacent radiator modules can be generated is. While with comparable dual polarized antenna arrays (So with antenna arrays where at the same time with two different polarized electromagnetic Shafts are working for the transmission) without adequate decoupling was required per base station antennas at least two spatially offset antenna arrays to be arranged separately for sending and receiving, see above can comparable results according to the invention today achieved with only one X-polarized antenna array be because of the high decoupling of more than, for example. 30 dB the antenna array for both sending and can also be used for receiving. Of course, this leads at a considerable cost advantage.

The solution according to the invention is therefore suitable on the basis of high achievable decoupling between the polarizations especially with antenna arrays with high vertical bundling for the mobile phone area.

According to the invention, these advantages are achieved by that between two neighboring radiator modules Decoupling device with a new type of decoupling structure is provided. This decoupling structure is completely different to the z. B. vertically aligned Antenna arrays used horizontal partitions or Rods, arranged exactly the opposite. The invention Decoupling structure has a longitudinal extension on, in the vertical mounting direction two side by side Arrays arranged (basically also with horizontal Direction of attachment of two arrays arranged side by side) is aligned. In other words, they are already good Results with a vertically aligned X-polarized Array e.g. then achieved when between two on top of each other arranged radiator modules in the vertical direction extending longitudinal rod is provided. As well it is possible, for example, that in the reflector surface or in another conductive surface in front of this reflector surface a longitudinal slot or another decoupling structure with an elongated recess or extension introduced is.

However, particularly favorable results are achieved if between two neighboring X-polarized radiator modules a decoupling device with a cross-shaped Decoupling structure in the form of a cruciform Structural element is used, which for example from two intersecting single bars (i.e. metallic conductive rods) or cross-shaped slots can, the slots in the reflector surface or a parallel, metallic conductive surface are introduced.

In a preferred embodiment, the conductive ones cross-shaped structural elements of the decoupling structure connected at their intersection.

Finally, it turns out to be favorable if the cross-shaped conductive structural elements in different

Layers lie to each other, but essentially not more than half a wavelength apart should lie.

Figur 1a :

eine schematische Draufsicht auf ein Antennenarray mit zwei Strahlermodulen und einer dazwischen vorgesehenen erfindungsgemäßen Entkopplungseinrichtung in Draufsicht;

Figur 1b :

eine Seitenansicht längs der Pfeilrichtung Ib in Figur 1a;

Figur 2a :

ein abgewandeltes Ausführungsbeispiel eines erfindungsgemäßen Antennenarrays mit einer kreuzförmigen Entkopplungseinrichtung in Draufsicht;

Figur 2b :

eine Seitendarstellung gemäß der Pfeilrichtung IIb in Figur 2a;

Figur 2c :

eine schematische Perspektivdarstellung des Ausführungsbeispieles gemäß Figur 2a und Figur 2b;

Figur 3a :

ein zu Figur 2a abgewandeltes Ausführungsbeispiel, bei welchem als Strahlermodule sog. Patchstrahler verwendet werden;

Figur 3b :

eine Seitendarstellung von Figur 3a gemäß Pfeilrichtung IIIb in Figur 3a;

Figur 4a :

ein weiteres Ausführungsbeispiel eines Antennenarrays in Draufsicht; und

Figur 4b :

eine entsprechende Seitendarstellung gemäß Pfeilrichtung IVb in Figur 4a.

The invention is explained in more detail below on the basis of exemplary embodiments. The individual shows:

Figure 1a:

a schematic plan view of an antenna array with two radiator modules and a decoupling device according to the invention provided between them in plan view;

Figure 1b:

a side view along the arrow direction Ib in Figure 1a;

Figure 2a:

a modified embodiment of an antenna array according to the invention with a cross-shaped decoupling device in plan view;

Figure 2b:

a side view according to the direction of arrow IIb in Figure 2a;

Figure 2c:

a schematic perspective view of the embodiment shown in Figure 2a and Figure 2b;

Figure 3a:

an exemplary embodiment modified from FIG. 2a, in which so-called patch radiators are used as radiator modules;

Figure 3b:

a side view of Figure 3a in the direction of arrow IIIb in Figure 3a;

Figure 4a:

a further embodiment of an antenna array in plan view; and

Figure 4b:

a corresponding page representation according to arrow direction IVb in Figure 4a.

The first is the embodiment received according to Figures 1a and 1b. In this embodiment is an antenna array with two radiator modules 1, which consists of a double dipole arrangement 3 exist. It can be, for example act a so-called cross dipole, which spatially around two 90 ° offset systems, which are separate be fed. Deviating from this can also other double dipole arrangements are used at which the individual dipoles in top view, i.e. in the preferred emission direction, for example a square structure have (so-called a dipole square). Finally can also emit more different radiator modules Reception of electromagnetic waves with two linear Orthogonal polarizations are used as they are explained below using so-called patch radiators become.

The radiator modules 1 are in front of a reflector 7 Dipoles at a distance from the reflector 7 sitting on it assembled. In the exemplary embodiment shown, the reflector 7 by a metallization 9 on a circuit board 11 formed on the back of a feed network 13th is located, which separates the individual radiator modules interconnects for the respective polarization. The dipoles 3 are compared via a so-called symmetrization 14 the circuit board 11 held mechanically and electrically contacted, d. H. so fed from the board 13.

In the exemplary embodiment shown, the two are shown Radiator modules 1 in vertical alignment V one above the other and again in parallel to the reflector plane arranged. The double dipole arrangement 3 is like this chosen that with the radiator modules 1 a linear polarization of + 45 ° and -45 °, based on the vertical V, can be received.

To achieve a high level of decoupling between the two Radiator modules 1 is in the illustrated embodiment a decoupling structure 17 according to FIGS. 1a and 1b provided, which consists of a conductive rod 17a. In the exemplary embodiment shown, this is in the middle between the two radiator modules 1 arranged, where the rod 17a in the connection or mounting direction 21 of the Radiator modules 1, i.e. on the direct connecting line is located between the adjacent radiator modules 1.

The longitudinal or extension component of the decoupling structure 17, which in the following also partially as a decoupling structural element 17 is according to the Embodiment according to Figure 1a or 1b larger than at least 1/4 of the distance between the two neighboring ones Centers or base points 23 of the radiator modules or corresponds 1/4 of this distance. The longitudinal component is preferably more than 40 or 50% of the said Spotlight module distance 25.

The rod 17a shown is a short distance above the Reflector surface 7 is arranged and is a spacer 18 on the reflector 7, i.e. mechanically held by the circuit board 11 and with the reflector 7 electrically contacted. Finally, the decoupling structure could but also further than the double dipole arrangement 3 be removed from the reflector surface 7, wherein however then influences on the radiation diagram at good decoupling can be determined if the distance of the decoupling structure 17 from the reflector surface is more than half as far away as the dipoles the double dipole arrangement 3. The arrangement is preferred such that the conductive decoupling structure 17 in shape of the rod 17a not more than 1/8 to 1/4 wavelength is removed from the reflector plane.

In practice, the arrangement can be such that the dipoles 3 'for example at a distance of 0.1 to 0.5 Wavelengths, preferably 0.2 to 0.3 wavelengths, in particular by 0.25 wavelengths, in front of the reflector surface sit, the decoupling structure in the form of the decoupling structure element 17a a distance of 0.015 up to 0.125 wavelengths, in particular 0.015 to 0.035 wavelengths (i.e. about 1/60 to 1/8, especially 1/60 to 1/30 of the wavelength), opposite the reflector surface 7 can have.

Finally, different from the embodiment shown the decoupling structure 17 is not in the form of a Rod, but in the form of a plan view of Figure 1a congruent to the rod shown there in the reflector surface 7 slot introduced. Is possible also an arrangement with a conductive surface at a distance in front of the reflector surface, in which a corresponding one Recess is introduced, which has a structure with a longitudinal extension, preferably parallel and in the area of the connection or mounting direction 21 lying.

The exemplary embodiment according to FIGS. 2a, 2b and 2c differs differs from the exemplary embodiment explained above in that for the decoupling structure 17 no rod extending in the connecting direction 21 17a, but a cross-shaped decoupling structural element 17b is used from two crossing bars. A schematic perspective illustration is shown in FIG. 2c of the embodiment shown in Figures 2a and 2b. The rods 27 are in this embodiment almost perpendicular to each other, the two rods almost parallel to the polarization planes, i.e. to the dipoles 3 'are aligned. The cruciform Decoupling structural element 17b with the rods 27 also conductive again, the two rods 27 in their intersection 29 are conductively connected.

The longitudinal component in the connection or mounting direction 21 of the cross-shaped decoupling structure 17 thus formed 0.25 to 1 wavelength, for example, preferably 0.5 to 0.8 wavelengths, especially around 0.7 Wavelengths. The projection is under "longitudinal component" on the vertical, i.e. on the direct connecting line between two neighboring radiator modules in To understand the direction of cultivation. Because of the symmetrical Structure is the extension in the transverse direction to the direction of attachment 21 of the same length, but this does not have to be mandatory.

In the exemplary embodiment according to FIGS. 3a and 3b deviating from the exemplary embodiment according to FIGS. 2a and 2b used as emitter modules. Patch emitters 1a, such as basically from the ITG technical report pre-publication 128 "antennas" (lectures of the ITG conference from April 12 to 15, 1994 in Dresden), VDE-Verlag GmbH, Berlin, Offenbach, pages 259 to 264 are known. It deals are aperture-coupled microstrip patch antennas with a cross slot or offset slot arrangement to receive two orthogonal linear Polarizations.

The patch radiators 1a have square shapes in plan view Structure on and are with their slot arrangement each again aligned at a 45 ° angle to the vertical V in order to both + 45 ° and -45 ° polarizations received or to be able to send.

Because of the square structure of this single-feed system 1 the effective distance between the outer contours between the two radiator modules 1 in the direction of attachment 21 is comparatively short, is suitable in particular a cross-shaped decoupling structure 17, as they are based on the embodiment of Figures 2a and 2b.

The exemplary embodiment according to FIGS. 4a and 4b differs differs from that according to FIGS. 3a and 3b only in that instead of in the form of intersecting Bars 27 formed and in front of the plane of the reflector 7 arranged cross-shaped decoupling structural elements 17b now a corresponding cruciform slot 17c is used as the decoupling structure, its arrangement and otherwise aligning the cruciform rod assembly 17b according to FIGS. 3a and 3b. The dimensioning can be similar to the cruciform Rod arrangement according to Figures 3a and 3b.

In the drawings is only in Figures 1a to 2c the mechanical anchoring and support of the dipoles 3 has been indicated on the reflector or the circuit board. It the usual constructions are used to for example via the mentioned symmetrizations 14 individual dipoles on a substrate or a circuit board anchor it and feed it electrically. Will the Dipoles, for example, via two webs or arms on the reflector plate anchored and held above and stand with the Reflector plate in a conductive connection, so the feed takes place the dipole from the board via separate Cables. Among other things, this is only an example to DE 43 02 905 C2 or others previously known therefrom Dipole devices referenced. In the further figures 3a the following is the mechanical support of the dipoles opposite the reflector or the board not shown.

Claims (17)

1. Antenna array for simultaneous reception and for simultaneous transmission of electromagnetic waves having two linear, orthogonal polarizations, in particular using a reflector (7), having the following features

   having at least two radiating element modules (1), the alignment of the antenna array is governed by the connection direction (21), in which the radiating element modules (1) are arranged alongside one another and/or one above the other,

   the radiating element modules (1) having a radiating element arrangement (3) for simultaneous reception or transmission of electromagnetic waves having two orthogonal polarizations,

   the connection direction (21) of the antenna array is rotated with respect to the alignment of the two mutually orthogonal polarization planes of the two linear orthogonal polarizations to be received or to be transmitted,

   having a decoupling device (17) between two adjacent radiating element modules (1),

   characterized by the following further features

   the decoupling device (17) comprises a decoupling structure (17) which extends with its longitudinal component parallel to the connection direction (21) of two adjacent radiating element modules (21), and

   the longitudinal component of the respective decoupling structure (17) having a length which is greater than or equal to 25% of the radiating element module separation (25) between the centres or bases (23) of the corresponding adjacent radiating element modules (1).
2. Antenna array according to Claim 1, characterized in that the longitudinal extent of the longitudinal component of the decoupling structure (17) in the connection direction (21) is at least 50% of the radiating element module separation (25).
3. Antenna array according to Claim 1 or 2, characterized in that the ratio of the longitudinal component of the decoupling structure (17) measured in its connection direction (21) to its extent in the direction of its transverse component is greater than 0.5 or is 0.5.
4. Antenna array according to Claim 3, characterized in that the ratio of the longitudinal extent in the connection direction (21) to the transverse extent, running at right angles to this, of the decoupling structure (17) is greater than or equal to 0.7 and less than or equal to 1.5, preferably greater than or equal to 0.9 and less than or equal to 1.1, in particular about 1.0.
5. Antenna array according to Claim 1 or 2, characterized in that the decoupling structure (17) is at least one electrically conductive rod (17a) extending with its longitudinal component in the connection direction (21), or a longitudinal element extending essentially in the connection direction (21).
6. Antenna array according to one of Claims 1 to 5, characterized in that the decoupling structure (17) comprises at least one slot (17c) which extends with its longitudinal component in the connection direction (21), and is formed in the reflector (7) or in a separate conductive surface arranged at a distance in front of the reflector.
7. Antenna array according to one of Claims 1 to 6, characterized in that the decoupling structure (17, 17a) is aligned at least virtually parallel to the direct connecting line between two adjacent radiating element modules (1) and, at the same time, preferably extends on the direct connecting line between two adjacent decoupling structures (17, 17a).
8. Antenna array according to one of Claims 1 to 7, characterized in that the decoupling structure (17) comprises a cruciform arrangement (17b, 17c, 17d).
9. Antenna array according to Claim 8, characterized in that the decoupling structure (17) comprises two, or a multiple thereof, rods (27) which are arranged at least approximately at right angles to one another, are conductive and are aligned with their respective longitudinal extent parallel to the two polarizations which are aligned orthogonally with respect to one another.
10. Antenna array according to Claim 9, characterized in that the decoupling structure (17) in the form of a cruciform arrangement (17b) comprises rods (27b) which are arranged in a cruciform manner with respect to one another and parallel to the reflector plane (7) and are conductively connected at their intersection (29).
11. Antenna array according to Claim 8, characterized in that the cruciform arrangement comprises a cruciform slot arrangement (17c) which is formed in the reflector (7) or in a conductive surface arranged in front of the reflector (7).
12. Antenna array according to one of Claims 1 to 11, characterized in that the decoupling structure (17) is formed on different separation planes with respect to the reflector (7), the distance from the reflector plane being less than or equal to half a wavelength of the electromagentic waves to be received or to be transmitted.
13. Antenna array according to one of Claims 1 to 12, characterized in that the decoupling structure (17) is formed symmetrically with respect to the direct connecting line between two adjacent radiating element modules (1) and thus symmetrically with respect to the connection direction (21).
14. Antenna array according to one of Claims 1 to 13, characterized in that the decoupling structure (17) is formed symmetrically with respect to a centre transverse plane at right angles to the direct connecting line between two adjacent radiating element modules (1).
15. Antenna array according to one of Claims 8 to 14, characterized in that the two mutually perpendicular components of the cruciform arrangement (17b, 17c, 17d) of the decoupling structure (17) are aligned parallel to the two mutually orthogonal polarization planes of the two linear orthogonal polarizations to be received or to be transmitted.
16. Antenna array according to one of Claims 1 to 15, characterized in that the radiating element arrangement (3) comprises a dipole radiating element arrangement.
17. Antenna array according to one of Claims 1 to 15, characterized in that the radiating element arrangement (3) comprises a patch radiating element arrangement (1a).

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