CA2506198C

CA2506198C - Two-dimensional antenna array

Info

Publication number: CA2506198C
Application number: CA2506198A
Authority: CA
Inventors: Max Goettl; Juergen Rumold
Original assignee: Kathrein Werke KG
Current assignee: Kathrein SE
Priority date: 2002-12-05
Filing date: 2003-12-04
Publication date: 2012-08-21
Anticipated expiration: 2023-12-04
Also published as: AU2003292188A1; DE10332619A1; EP1525642B1; KR101060067B1; ES2590911T3; CA2506198A1; WO2004051796A1; EP1525642A1; KR20050084836A; DE10332619B4

Abstract

The invention relates to a two-dimensional antenna array which is characterised by the following: at least two vertically extending gaps (5a, 5b) are present in said array; a radiator arrangement is respectively provided in each of the at least two vertically extending gaps (5a, 5b), said arrangements being separately fed; the radiator arrangement provided each gap (5a, 5b) respectively comprises at least one radiator or a radiator group (9);
at least one additional radiator or an additional radiator group (109b or 109a) is provided for at least one gap (5a, 5b) in such a way that it is vertically staggered in relation to the radiator arrangement provided; and the at least one additional radiator or the at least one additional radiator group (109b or 109a) is fed by means of the radiator arrangement located in the other gap (5b or 5a).

Description

TWO-DIMENSIONAL ANTENNA ARRAY
The invention relates to a two-dimensional antenna array.

A generic antenna array normally comprises two or more antenna elements or antenna element groups, but at least two antenna elements or antenna element groups which are arranged alongside one another and two antenna elements or antenna element groups which are arranged one above the other, thus resulting in a two-dimensional array arrangement. By way of example, a two-dimensional antenna array such as this may have four vertically running columns which are arranged horizontally alongside one another, in each of which, for example, six to ten antenna elements or antenna element groups which are arranged offset one above the other in the vertical direction are arranged.
Antennas such as these are then in some cases also referred to as "smart antennas", depending on the purpose, and may also be used, for example, inter alia in the military field for target tracking (radar). The expression "phased array" antenna is also frequently used in these applications. These antennas are, however, also increasingly being used recently for mobile radio, in particular in the 800 MHz to 1000 MHz and 1700 to 2200 MHz frequency bands.

The design of dual-polarized antenna arrays, in particular with a polarization alignment of +45 and -45 with respect to the horizontal or vertical, has now also been made possible by the development of new primary antenna element systems.

Irrespective of whether they are in principle dual-polarized or comprise only single-polarized antenna elements, antenna arrays such as these may be used to determine the direction of the incident signal. At the same time, however, the transmission direction can also be varied, that is to say selected beamforming is carried out, by appropriately adjusting the phase angle of the transmission signals which are fed into the individual columns.

This alignment of the transmission direction of the antenna array in a different horizontal direction can be carried out by electronic beam swiveling, that is to say the phase angles of the individual signals can be adjusted by means of suitable signal processing.
Suitably designed passive beamforming networks are likewise also possible. The use of active phase shifters or phase shifters which can be driven by control signals in these feed networks is also known, for variation of the transmission direction. A
beamforming network such as this may, for example, be formed by a so-called Butler matrix which, for example, has four inputs and four outputs. Depending on which input is connected, the network produces a different but fixed phase relationship between the antenna elements in the individual dipole rows. An antenna design such as this with a Butler matrix has been disclosed, for example, in US 6,351,243, which forms this generic type.

The electronic swiveling of the horizontal polar diagram can likewise be carried out by the use of permanently set phases or by the use of phase shifters between the columns. The vertical polar diagram can likewise be raised or lowered (downtilt) by means of permanently set phases or by the use of phase shifters.
In addition, of course, the antenna array can also be used in such a way that the individual antenna elements or antenna element groups in the individual columns are operated independently of one another in order to be used independently of one another in a desired transmission or reception mode.

Antenna arrays such as these have a polar diagram for the antenna elements or antenna element groups which are arranged individually in one column and whose 3 dB
beamwidth extends between approximately 80 and 100 in the horizontal direction.
However, operational situations have become known in which, for example, it is normally desirable to have a 3 dB beamwidth in the order to magnitude of 60 to, for example 65 .
In this case, attempts have already been made to arrange the antenna elements or antenna element groups at different horizontal positions in the individual columns. This allows the 3 dB beamwidth of the individual antenna elements or antenna element groups in a column to be influenced in a specific manner, thus allowing 3 dB beamwidths of between 75 and 100 to be achieved. However, the 3 dB beamwidth cannot be reduced any further in this way.
The object of the present invention is thus to provide an antenna array which provides the capability in at least one column, and preferably in two or more or all of the columns, to also reduce the horizontal 3 dB
beamwidth of the antenna elements. or antenna element groups in the individual columns to values below 75 .
According to one aspect of the invention, the object is achieved with a two-dimensional antenna array comprising:
at least two vertically oriented columns, at least one of said columns comprising at least two radiators or radiator groups arranged in a vertical direction and vertically offset with respect to each other;
at least one additional radiator or radiator group provided for said at least one column, said at least one additional radiator or radiator group being fed commonly with the radiators or radiator groups provided in said at least one column, the additionally provided at least one radiator or radiator group for said at least one column being arranged horizontally offset to the other radiators or radiator groups provided in said at least one column.

According to the invention, it is possible without enlarging the overall antenna structure to reduce the 3 dB beamwidth of the column antenna elements by providing at least one additional antenna element or at least one additional antenna element group, which is preferably accommodated in an adjacent column, for the antenna elements or antenna element groups which are arranged vertically one above the other in one column, but horizontally offset with respect to them. This at least one additional antenna element or this at least one additional antenna element group is, however, not fed with the antenna elements or antenna element groups in the relevant column in which they are arranged, but is fed jointly with the antenna elements or antenna element groups in the adjacent column. This allows the -4a-3 dB beamwidth to be considerably reduced, with the capability to set the optimum, desired 3 dB beamwidth in a preferred manner by suitably choosing the number of antenna elements or antenna element groups which are associated with one specific column but are offset with respect to it. In practice, it has been found that, for example, the use of two additional antenna elements or antenna element groups is sufficient to achieve a 3 dB
beamwidth of about 600 to 65 for an antenna array having six to twelve antenna elements or antenna element groups which are arranged one above the other.
The solution according to the invention may be used when the antenna elements which are used in the -individual columns are in the form of linear-polarized antenna elements, or else are in the form of dual-polarized or circular-polarized antenna elements. In this case, all suitable antenna elements may be 5 considered, for example dipole antenna elements in the form of conventional dipole antenna elements (particularly for linear-polarized antennas) or, for example, dipole arrangements in the form of a dipole square, but transmitting in the form of a dipole cruciform, as are in principle known, for example, from WO 00/39894. Likewise however, it is also possible to use dipole squares or else patch antenna elements etc.
Particularly in the case of cruciform antenna element arrangements, these arrangements can preferably be aligned at an orientation of +/-45 to the horizontal and vertical.

The column separation, that is to say the distance between the antenna elements or antenna element groups between two adjacent columns, is preferably approximately X/2 of the mean operating wavelength.
However, in principle, this column separation may also be in a range from 0.25 X to 1.0 X of the operating wavelength, preferably of the mean operating wavelength. The vertical separation between the antenna elements in one column is preferably 0.7 ? to 1.2 X. If integration is intended between an additional antenna element or additional antenna element groups (which is fed jointly with the antenna elements in an adjacent column), then the free distance to an upper or lower antenna element or lower antenna element group is preferably reduced to half this distance.

As explained, the antenna according to the invention can be operated in such a way that the antenna elements or antenna element groups which are in principle provided in one column are fed and operated independently of those in an adjacent column (naturally with the exception of the additional antenna elements or antenna element groups integrated according to the invention, which are fed jointly with those in an adjacent column). Those antenna elements or antenna element groups which are provided ex-works in one column can preferably be driven via phase shifters, which make it possible to set a different downtilt angle with respect to a horizontal plane.

As in the case of the prior art as well, in an antenna array such as this, the phase with respect to the antenna elements or antenna element groups which are associated with the individual columns can also be varied by remote control by means of, in particular, electromechanical control devices which are integrated or can be retrofitted, in such a way that it is possible to produce a respectively desired downtilt setting in the individual columns.

Finally, however, an antenna array of the described type can also be used to carry out beamforming of any desired type, particularly when a so-called Butler matrix or similar beamforming networks is or are connected upstream of the individual columns and the antenna elements or antenna element groups which are provided there. As an alternative to this, hybrids can also be connected within the individual columns.

The columns are preferably separated by uniform intervals alongside one another, although it is also possible to produce antenna arrays with non-uniform intervals between them, alongside one another.

Finally, the individual antenna elements or antenna element groups in the individual columns can each be arranged at the same height or else can each be arranged offset with respect to one another in the vertical direction. In this case, the mid-position of an antenna element or of an antenna element group in one column can be arranged at any desired relative vertical height with respect to the respective position of the antenna elements or antenna element groups provided there. However, the vertical offset may also correspond exactly to half the vertical separation between two antenna elements or antenna element groups which are arranged one above the other.

if the antenna elements or antenna element groups in two adjacent columns are arranged offset with respect to one another in the vertical direction, then this offers the advantage that the additionally provided antenna element or elements or antenna element group or groups which is or are associated with one specific column but are arranged in an adjacent column can be arranged in such a way that they are located on the same height line alongside an antenna element or antenna element group in the column associated with them. In the end, this makes it possible to produce an optimized antenna without increasing its physical size.
The additionally provided antenna elements or antenna element groups for reducing the 3 dB beamwidth can in this case be arranged both approximately centrally and at the upper and/or lower end of a column. They can also be arranged at any desired position in between.
These position measures allow fine optimizations to be implemented.
In order to minimize the 3 dB beamwidth in the desired manner, at least one additional antenna element or one additional antenna element group is in each case provided, as mentioned, for one column, and these are integrated in an adjacent column offset horizontally or with horizontal or vertical components. At most, the number of these additional antenna elements or antenna element groups corresponds to the Figure N-1, where N

corresponds to the number of antenna elements or antenna element groups provided ex-works in one column.
One preferred embodiment provides for all of the antenna elements or antenna element groups in one column to be arranged offset at the same distance from one another in the vertical direction, with at least one antenna element or one antenna element group, and possibly also two or more of them, each being fed together with the antenna elements or antenna element groups in an adjacent column. This makes it possible, for example, to arrange each of the antenna elements or antenna element groups in two adjacent columns on the same height line, that is to say in pairs on the same height line, in which case a pair of antenna elements or antenna element groups such as these are then in each case fed alternately with the antenna elements or antenna element groups which are located in the other column.

Another aspect of the invention concerns a two-dimensional antenna array comprising:
at least two columns running vertically, at least one column having at least two radiators or radiator groups arranged in a vertical direction with respect to each other;
the at least one column having at least two radiators or radiator groups vertically offset from one another;
at least one additional radiator group which is fed commonly with the radiators or radiator groups in said at least one column, the at least one additional radiator group for said at least one column arranged horizontally offset to the other radiators or radiator groups in the column.

- 8a -Yet another aspect of the invention concerns a two-dimensional antenna array having plural vertically-oriented radiator columns, said array including at least one radiator column comprising:
a first set of vertically offset radiators; and a further set of radiators horizontally offset from said first radiator set;
wherein said first and further radiator sets are fed in common.

Still another aspect of the invention concerns a two-dimensional antenna array defining at least two vertically running gaps, the antenna array comprising:
at least two radiators offset to one another in the vertical direction in at least one of said gaps, the radiators in said at least one gap except for at least one radiator being jointly fed, and said at least one radiator in at least one of said gaps being fed jointly with some but not all of the radiators of a gap adjacent to said at least one gap.

Yet another aspect of the invention concerns a two-dimensional antenna array comprising:
a structure defining at least first and second gaps extending vertically when the antenna is in use;
plural radiators disposed at least partially within said first gap, said plural radiators being offset from one another in the vertical direction; and at least one radiator at least partially disposed within said second gap, wherein at least one of said plural radiators within said first gap and said at least one radiator but not all of the radiators within said second gap are jointly fed.

- 8b -Still another aspect of the invention concerns a two-dimensional antenna array comprising:
a structure defining at least first and second columns extending vertically when the antenna is in use;
plural radiators disposed at least partially between said first column and said second column, said plural radiators being offset from one another in the vertical direction; and at least one further radiator at least partially disposed outside of a space between said first column and said second column, wherein at least one of said plural radiators and said at least one further radiator but not all of the further radiators are jointly fed.

The invention will be explained in more detail in the following text using exemplary embodiments. In detail, in the figures:

Figure 1 shows a schematic front view of a two-column antenna array according to the invention;

Figure la shows a detail from a schematic perspective illustration of a so-called dipole antenna element as is used in the exemplary embodiment shown in Figure 1;

Figure 2 shows a detail illustration of the antenna array according to the invention as shown in Figure 1, with antenna elements or antenna element groups in only one column and the additional horizontally offset antenna elements or .-antenna element groups which are provided according to the invention in an adjacent column;
Figure 3 shows a corresponding illustration of a detail of the antenna array shown in Figure 1, but showing the antenna elements or antenna element groups which are provided ex-works in the second column and the further horizontally offset antenna elements or antenna element groups provided according to the invention;
Figure 4 shows a modified exemplary embodiment of the antenna array shown in Figure 1;
Figure 5 shows a further modified exemplary embodiment;

Figure 6 shows yet another modified exemplary embodiment;

Figure 7 shows a further exemplary embodiment, modified from that shown in Figure 1, comprising a large number of cruciform dipole antenna element groups (cruciform antenna elements);
Figure 8 shows a further exemplary embodiment using dipole squares, which are composed of dipoles, for the individual antenna element groups;
Figure 9 shows a further exemplary embodiment, modified from that shown in Figure 1, for a two-column antenna array using patch antenna elements;

Figure 10 shows a further modified exemplary embodiment using single-polarized antenna elements, preferably linear-polarized dipole antenna elements, which, on the basis of this exemplary embodiment, are aligned in the vertical direction;
Figure 11 shows yet another modified exemplary embodiment;

Figure 12 shows a further exemplary embodiment of a two-column array;

Figure 13 shows an exemplary embodiment which has been slightly modified from that shown in Figure 12; and Figure 14 shows an exemplary embodiment of a four-column antenna array.

Figure 1 shows a schematic plane view of an antenna array 1 according to the invention, which normally has a reflector 3 at the rear, which runs vertically when the antenna array is aligned vertically. By way of example, the reflector 3 may be in the form of an electrically conductive plate or a plate which is provided with an electrically conductive surface, in which case it is possible to provide angled webs, or even webs which run at right angles to the reflector plane and extend over a certain height with respect to the reflector plane, at the vertical outer boundaries.
In the illustrated embodiment, the antenna array 1 has two columns 5. Two or more, that is to say at least two, primary or first, that is to say fundamentally provided, antenna elements or antenna element groups 9 are arranged.. offset in the vertical direction with respect to one another in each of the columns 5 with, by way of example, the left-hand column 5a being fed via two inputs 11a, to be precise via one input for each polarization. Only one input lla would be provided for a single-polarized, for example vertically polarized, antenna. This means that all of the eight antenna elements or antenna element groups 9 which are illustrated in a darkened form in Figure 1 and are arranged at regular vertical distances one above the other are fed with the same phase angle via one input Ila. If only one antenna array with a single polarization, for example vertical polarization, were to be used instead of a duel-polarized antenna array arrangement, then the respective single-polarized antenna elements or antenna element groups which are arranged one above the other will be fed via only a single input 11. If it is desirable to also set a different downtilt angle from the electrical point of view for the antenna array (that is to say with different transmission angles with respect to the horizontal plane), then various phase shifters can also be integrated in the antenna array, by means of which the individual antenna elements which are arranged vertically one above the other, or groups of antenna elements which are arranged one above the other, could be fed with different phase angles. Once again, this therefore means that two inputs 11a are provided for each polarization for one column, in which case the phase angle for the antenna elements or antenna element groups which are arranged vertically one above the other can be set differently by means of the feed network, which is not shown in any more detail but, for example, has two or more phase shifters. In this context, reference should be made, for example, to the previously published WO 01/13459, whose contents are included in this application.

The eight antenna elements or antenna element groups 9 which are provided in the right-hand column 5b and are arranged at regular vertical intervals one above the other are likewise fed with the same phase angle via two second inputs llb or, if a feed network is used having one or more phase shifters, with a different phase angle in order to produce a downtilt angle.

In the illustrated exemplary embodiment, the antenna elements or antenna element groups 9 are in this case in the form of so-called cruciform vector dipoles which are aligned with their radiated direction at +450 and -450 to the horizontal or vertical. The design and method of operation of these antenna elements (which appear to be approximately rectangular in the schematic illustration shown in Figure 1 but the electrical effect of whose polarization is in the form of cruciform dipoles on two mutually perpendicular planes) are fundamentally known from WO 00/39894, whose entire disclosure content is referred to and is included in the contents of this application. However, instead of these so-called cruciform vector dipoles, it is also possible to use conventional cruciform dipoles, dipole squares or patch antenna elements, etc., when the individual antenna elements or antenna element groups are each intended to radiate on two mutually perpendicular polarization planes. This will also be described later with reference to further schematic figures.

Since, in principle, the antenna elements in each of the two columns 5a and 5b ideally have a 3 dB beamwidth which is not less than 75 , the invention now provides for additional antenna elements or antenna element groups to be provided.

In order to assist understanding, reference is therefore also made to Figure 2 which, although it also shows the same antenna array shown in Figure 1, illustrates only those antenna elements and antenna element groups 9 which are provided in the left-hand column 5a in the antenna array shown in Figure 1 (as has.already been explained with reference to Figure 1).
In other words, those antenna elements or antenna element groups 9 which belong to the second column and are shown in a lightened form in Figure 1 have been omitted in the example shown in Figure 2. Now, in this exemplary embodiment, two additional antenna elements or antenna element groups 109, 109a are provided in order to' reduce the 3 dB beamwidth of the antenna elements in the first column 5a and are arranged offset with respect to the first column 5a, preferably in the second column 5b in the exemplary embodiment. These are fed jointly with those antenna elements or antenna element groups 9 which are provided ex-works in the first column. These additional horizontally offset antenna elements and antenna element groups 109a can now be used to reduce the 3 dB beamwidth. In this case, the magnitude of the 3 dB beamwidth with respect to the two central antenna elements or antenna element groups 9' is, for example, even focused at 45 . However, only one 3 dB beamwidth is perceived in the far field, so that the overall 3 dB beamwidth reduction is produced, for example to a desired range of about 60 or 65 .

In a corresponding manner, additional antenna elements or antenna element groups 109, 109b are also provided for the antenna elements or antenna element groups 9 for the second column 5b and, as can be seen in particular from Figure 3, are likewise arranged offset in the direction of the first column 5a in the center.
These additional antenna elements or antenna element groups 109, 109b are also fed jointly with the antenna elements or antenna element groups 9 in the second column 5b. The additional antenna elements 109b in the column 5a are in this case arranged on the same height line as the.. adjacent antenna elements or antenna element groups 9" in the second column 5b.

Finally, the antenna shown in Figure 1 is composed of the two antenna parts shown in Figure 2 and Figure 3.
Since the exemplary embodiment shown in Figures 1 to 3 also provides for the antenna elements or antenna element groups in the first column 5a to be arranged offset by half the vertical interval between two antenna elements or antenna element groups 9 which are arranged in the adjacent column, this makes it possible for the additional antenna elements or antenna element groups 109, 109a or 109, 109b each to be located at the same height in order to reduce the respective 3 dB
beamwidth in the respective other column with respect to this, to be precise between two vertically adjacent antenna elements or antenna element groups which are provided there.

As has already been stated, the two-column antenna array can be provided without any downtilt facility.
All of the antenna elements 9 are then fed uniformly for both polarizations via the feed inputs lla and llb.
The additional antenna elements 109a and 109b which are provided in addition to the respective main group 5a or 5b and are then effectively arranged in an adjacent column can thus each be fed with the same phase angle as those antenna elements which belong to the respective main column. If, however and by way of example, an integrated feed network is used in order to feed each of the antenna elements which are arranged vertically one above the other with a different phase angle (or, for example, to feed two and only two groups of antenna elements which are arranged one above the other with a different phase angle) , that is to say in order to make it possible to set a different downtilt angle, then it is recommended that the additional antenna elements or antenna element groups 109a, 109b, which are in each case associated with the antenna elements provided in a main column but are arranged in an adjacent column, be fed as far as possible with the same phase angle or with the nearest possible phase angle that is used to feed that antenna element which is also located adjacent in the respective main column.
if the polar diagram is lowered in a corresponding manner with a specific downtilt angle, it should thus be possible, for example in the case of the exemplary embodiment shown in Figure 1, to feed the antenna element 9' which is arranged in the left-hand column 5a with the same phase angle as that for the additional antenna element 109'a which is arranged in the adjacent column. The further antenna element 9" which is located underneath this may, for example, be fed with a phase angle which has been shifted once again, but together with the antenna element arrangement 109"a located in the adjacent column. A corresponding situation applies to the additional antenna elements 109b, which are shown in a lightened form in Figure 1 and are fed with the corresponding identical phase angle (to be precise likewise separately for each polarization) as the antenna elements located to the right of them in the column 5b.

In addition, reference is also made to Figure la, which shows a detail of an enlarged detailed illustration of the antenna shown in Figure 1, in the form of a perspective illustration. This also shows that an edge boundary 3' can also be provided externally on the vertical edge of the reflector, extending essentially at right angles to, or at least transversely with respect to, the reflector plane 3. The individual columns 5a and 5b can also be separated or subdivided in-between them by a further boundary wall or boundary web which preferably extends at right angles to the reflector plane and may also have a different height from that of the external reflector boundaries 31.

In an entirely general form, the antenna array according to the invention, which has been explained so far with reference to Figures 1 to 3, can be designed in its simplest form such that it has only two vertically running columns 5a and 5b. In this case, one antenna element arrangement is provided in each of the at least two vertically running columns 5a and 5b, and this antenna element arrangement is fed. The antenna element arrangement which is provided in the two columns 5a and 5b in this case has at least one antenna element or at least one antenna element group 9 in each case. The invention now also provides for at least one further additional antenna element or at least one further additional antenna element group 109b or 109a to be provided at least for one column 5a or 5b and offset in the vertical direction with respect to the antenna element arrangement that is already provided there, and for the at least one additional antenna element or the at least one additional antenna element group 109b or 109a to be fed together with the antenna element arrangement which is arranged in the other column 5b or 5a.

The exemplary embodiment shown in Figure 4 differs from that shown in Figure 1 in two respects, specifically first by the fact that only one additional antenna element or one additional antenna element group 109a or 109b is provided for each column 5, and on the other hand by the fact that, rather than being arranged in the central area of the antenna array, it is arranged laterally offset with respect to the antenna element that is arranged at the top or bottom. This also results in a reduction of the 3 dB beamwidth of all the antenna elements or antenna element arrangements in a respective column.

In the exemplary embodiment shown in Figure 5, two additional antenna elements or antenna element arrangements 109a and 109b are once again provided for each column, to be precise at the upper end and at the lower end, or end area, of the antenna array.

In the exemplary embodiment shown in Figure 6, the antenna elements or antenna element groups 9 which are provided ex-works in each column 5 are arranged at the same horizontal height as one another, that is to say in pairs. In this case, the additionally provided antenna elements or antenna element groups 109, which are mounted alternately in the adjacent column, must be provided at an intermediate height with respect to the antenna elements or antenna element groups which are provided in the respective main column, as can be seen from Figure 6.

Particularly when a feed network is once again provided for setting a different downtilt angle, the additional antenna elements 109a and 109b which are provided for a respective main column 5a or 5b and are arranged in the column 5b or 5a which is in each case arranged adjacent to it can in this case be fed with a phase angle which either corresponds to the optimum phase angle on the basis of their horizontal arrangement, or else have a phase angle which, for example, matches that of the antenna elements which is arranged immediately above or immediately below in the associated main column 5a or 5b. Thus, in the exemplary embodiment shown in Figure 6, for example, the upper additional antenna element 109'a could have a phase angle which corresponds either to the phase angle of the antenna element 9' or antenna element 9" in the associated main column 5a. The additional antenna element 109"a which is provided in the column 5b could once again have a phase which corresponds to the phase angle of the antenna element 9" or 9"' provided in the main column 5a. The same also applies, of course, to the additional antenna elements 109b which are provided in the column 5a and are operated together with the corresponding antenna elements which are arranged in the associated main group 5b.

As can be seen from Figure 7, an identical antenna element arrangement to that shown in Figure 1 can also be designed, for example using conventional cruciform antenna elements.

Figure 8 in this case shows that, by way of example, dipole squares can also be used instead of the cruciform antenna elements.

Figure 9 shows a corresponding exemplary embodiment using patch antenna elements.

With an appropriate alignment, all the antenna arrays which have been mentioned above are designed such that they transmit or receive on two mutually perpendicular polarization planes which are aligned at +45 and -45 to the horizontal or vertical.
The exemplary embodiment shown in Figure 10 shows an antenna array having two columns 5 with only vertically polarized dipoles. This example shows that the antenna elements or antenna element groups do not necessarily need to be composed of dual-polarized antenna elements (or, for example, circular-polarized antenna elements), but can just as well be composed of linear-polarized antenna elements or antenna element groups.

In all of the examples, the same technical measures reduce the 3 dB beamwidths of the polar diagrams of the individual columns 5.

Finally, reference is also made to Figure 11, which describes a further variant. The two-column antenna array 1 shown in Figure 11 is fundamentally similar to the exemplary embodiment shown in Figures 1 to 3. The special features are firstly that in principle only an odd number of main antenna elements 9 are initially arranged in each column, specifically nine antenna elements 9 arranged one above the other in the same vertical section in the column 5a in this exemplary embodiment, in the same way as in the column 5b. The odd number of main antenna elements in each column means that there is always one antenna element 9' at the center of the antenna array.

In this exemplary embodiment, two additional antenna elements 109a, specifically 109'a and 109"a, are provided for the antenna elements which are provided in the column 5a, and are now arranged between the antenna elements 9 offset by half the vertical interval corresponding to the vertical interval grid size. If the antenna is also once again operated with a specific downtilt angle, that is to say with the antenna elements 9 which are arranged vertically one above the other in one column being fed with a different phase angle, then the additionally provided antenna elements 109'a and 109"a are preferably fed with the same phase angle in this exemplary embodiment as that in the associated main column, that is to say in this case the antenna elements 9' which are provided in the column 5a and are arranged centrally. A corresponding situation applies to the antenna elements that are shown in a lightened form in Figure 11. There, the central antenna element in the column 5b is fed with the same phase angle as the two additional antenna elements 109b which are offset with respect to it and are provided in the column 5a. It would, of course, likewise be feasible, for example, to feed the additional antenna elements 109'a with the same phase angle as the antenna element 9". Further additional antenna elements 109"a could be fed with the,-same phase angle as the lower antenna element 9"'. This would also result in a high degree of symmetry. In addition, it should also be noted that the antenna elements or antenna element groups 9 in one column 5 are separated by a distance, for example, of between 0.25 X and 1 ? from the respective antenna elements or antenna element groups 9 in the adjacent column 5b, preferably being separated by X/2. In this case, X represents the wavelength of the operating wavelength, preferably the mid-operating wavelength in a frequency band to be transmitted. The vertical separation between the individual antenna elements in the individual columns preferably differs by between 0.7 X and 1.3 X.

In contrast to the illustrated exemplary embodiments, it would also be possible to provide antenna arrays having three, four or even more columns, with the columns preferably being separated from one another by uniform intervals in the horizontal direction. However, columns with non-uniform separation intervals between them are also possible.

The exemplary embodiments have been used to show that the number of the additional antenna elements which are additionally integrated in the respective other column include at least one antenna element or at least one antenna element group 109, 109a or 109b. The maximum number of these additionally provided antenna elements 109a, 109b is preferably restricted to a total which is one less than the number of "antenna elements or antenna element groups which are provided" in the associated main column.
The respectively additionally provided antenna elements or antenna element groups 109, 109' need not be provided exactly on the vertical line on which the antenna elements or antenna element groups of the respective adjacent column are arranged. In other words, an additional offset can be provided in the horizontal direction in this case.
The additional antenna elements or antenna element groups according to the invention which have been explained make it possible to achieve 3 dB beamwidths of, for example and preferably, 45 , 500, 55 , 60 , or else 65 or 70 , or any other desired intermediate values. In this case, it is also possible not to provide one or more columns with the additionally integrated antenna elements which have been explained, so that conventional 3 dB beamwidths of, for example, 75 , 80 or 85 can be provided in this case for this column.

As is evident from the exemplary embodiments which have been explained, the individual columns 5, 5a, 5b, etc.
can be electrically set independently of one another, preferably by means of suitable phase shifters.
However, the columns can also just as well be electrically set jointly, preferably via coupled phase shifters. If the examples of the antenna arrays which have been explained are provided with an integrated electromechanical unit, then the main antenna elements (main lobe) of the respective antenna elements which are arranged in one column can be lowered electrically by means of remote control. If required, retrofitting can also be carried out in this case in order to carry out remotely controlled lowering.

Finally, however, the columns can also be operated together, for example, by means of a Butler matrix or other upstream beamforming networks in order to carry out such beamforming.

The columns may, however, also be connected to hybrids I

in order to make it possible to carry out beamforming.
Finally, the antenna can also be provided with a calibration device in order to define the phase angles of the individual columns.

All of the described exemplary embodiments are based on the assumption that the additionally provided antenna elements are always fed jointly with the same phase angle together with the antenna elements which are actually provided in an adjacent column. However, fundamentally, it would also be possible to feed the additional antenna elements or antenna element groups which are provided for one column and antenna elements or antenna element groups which are arranged laterally offset with respect to this column in addition with an electrical phase which is not the same as that of the associated column, by which means the "tracking method"
can also be changed.
In the exemplary embodiment shown in Figure 12, an antenna array is provided having two columns 5, that is to say a column 5a and a column 5b, in which antenna array a large number of dual-polarized antenna elements 9 are arranged one above the other at regular vertical intervals.

In this case, the antenna elements 9 which are shown in a lightened form in Figure 12 in the left-hand column 5a are fed jointly. As can be seen from the illustrated exemplary embodiment, one antenna element 109b is shown in a darkened form among the antenna elements in the left-hand column 5a - in this exemplary embodiment in the center, although this is not absolutely necessary.
In the case of a conventional antenna array according to the prior art, this antenna element 109b, which is shown in the center of the left-hand column 5a and is shown in a darkened form, would likewise be fed together with the other antenna elements in this column 5a. In this case, the vertical interval between all of the illustrated antenna elements 9 in the left-hand column 5a would be arranged in their entirety, or the majority of them, vertically one above the other at the same grid interval. However, in contrast to the prior art, provision is now made for the antenna element which is provided per se in the center and is provided in addition with the antenna elements 9 which are jointly fed in the left-hand column 5a and are shown in a lightened form here, not to be arranged in the left-hand column, but now to be arranged, offset with respect to this, in the right-hand column 5b, where it is identified by the reference symbol 109a and is shown as being located in the center of the right-hand column. All of the antenna elements which are shown in a lightened form and are located in the left-hand column 5a are now fed jointly together with the antenna element 109a, which is likewise shown in a lightened form and is arranged in the right-hand column 5b. The vertical grid sequence, that is to say the vertical interval, or in general terms that is to say the vertical component of the physical interval between two respectively adjacent jointly fed antenna elements 9, 109, thus remains the same. This is because an antenna element 109 has been taken and has been positioned in an adjacent column 5b only on the basis of a conventional antenna array according to the prior art.
Nevertheless, all these antenna elements which are shown in a lightened form in Figure 12 are fed jointly.
The same is true of the antenna elements 9 which are shown for the right-hand column 5b in the exemplary embodiment in Figure 12 where, in principle, they are shown in a darkened form. Finally, the exemplary embodiment shown in Figure 12 results solely from the fact that, on the basis of a conventional antenna element, the antenna elements 109a and 109b which are positioned per se on one height line are not arranged in the column. in which they are jointly fed together with the remaining antenna elements 109, but that these two antenna elements 109a, 109b which are located on the same height line have their positions interchanged, so that the antenna element 109a, which is fed together with the antenna elements 9 which are located in the column 5a, is now located in a different column which is offset with respect to this, in general in an adjacent column 5b, and in that, conversely, the antenna element 109b, which is located with the antenna elements 9 which are jointly fed in the right-hand column 5b, is now positioned in the left-hand column.
The exemplary embodiment shown in Figure 12 could likewise also be interpreted as if at least one pair of antenna elements 109a, 109b were fixed on just one common height line and were not fed jointly together with the antenna elements which are located in the same column, but, instead, were in each case fed alternately jointly with the antenna elements in an adjacent group.
In contrast to the exemplary embodiment shown in Figure 12, it would, of course, also be possible to take in each case one further pair of antenna elements on other height lines, in the case of which the relevant antenna element is not fed jointly with the further antenna elements which are located in the same column, but is fed together with the antenna elements which are arranged in an adjacent column.
In contrast to the exemplary embodiment shown in Figure 12, the number of antenna elements or antenna element groups which are provided in total in each column may, of course, be greater or less than the number shown in the illustrated exemplary embodiment.
The number of antenna elements in the individual columns likewise need not be the same. Even the nature of the antenna elements which are used may be chosen to be different, for example being in the form of a dipole cruciform, a.dipole square, a so-called vector dipole, as has been explained with reference to the exemplary embodiment shown in Figure 12, etc. The antenna elements 109a and 109b which are located in a different column in Figure 1 could also be arranged offset outwards so that the overall width of the antenna array would thus become twice as great. However, this would only involve unnecessary physical space, for which reason a much more efficient, space-saving approach is that which has been explained with reference to Figure 12. This is because the lateral offset between the antenna elements 109a and 109b can be produced there without any additional physical space being required.

An antenna array corresponding to that shown in Figure 12 (although fundamentally likewise also with respect to Figure 13 or Figure 14 which will also be explained in the following text) makes it possible to use each of the jointly fed antenna elements as an antenna which is operated separately from the majority of the antenna elements which are arranged in a different column and are fed jointly. This is also possible because the jointly fed antenna elements are normally adequately decoupled from the other antenna elements even though they can normally be used in the same frequency band or frequency range. During transmission, however, only one antenna is normally used, that is to say, for example, the antenna elements 9 which are located in the left-hand column 5a in Figure 12 and are shown in a lightened form there, together with the antenna elements 109a which are located in the right-hand column, are arranged centrally and are likewise shown in a lightened form.
This at least one additional antenna element unit 109a in this case changes the beamwidth in the horizontal direction, in consequence preferably making it possible to reduce the beamwidth. Otherwise, without this additional antenna element unit 9a arranged in the other column, the 3 dB beamwidth of an antenna design in the form of columns such as this would necessarily be between 80 and 1000, that is to say in' particular around 90 , in which case this 3 dB beamwidth could in practice not be changed or reduced. Since the antenna arrays under discussion can preferably also be used as so-called smart antennas, in which the antenna elements which are located in two or more columns are used to carry out beamforming, in order to make it possible to set the main lobe of the antenna array to different azimuth directions, it is necessary, in particular, for the horizontal distance between the centers of the antenna elements, that is to say the horizontal distance between vertical lines on which the antenna elements 9 are arranged in two adjacent columns, to be approximately ?/2 (with the discrepancy preferably being intended to be less than 20% or less than 10%, or even less than 5%), this makes it harder to find a solution to reduce the radiation spectrum of a single antenna to considerably less than a 3 dB beamwidth of 90 . This is also possible by means of the solution according to the invention with the arrangement of one or more antenna elements or antenna element groups in an adjacent column. Particularly during reception, the antenna array can likewise once again be operated separately in terms of the radiation for individual columns or can in fact be interconnected in two or more columns.

Figure 13 differs from Figure 12 firstly only in that only nine antenna elements rather than eleven antenna elements are arranged one above the other in one column. However, this is relatively insignificant because the number of antenna elements which are arranged one above the other in the individual columns may in any case change as required.

The only function of Figure 13 is to show that the horizontal offset between the two central antenna elements 109a and 109b, which are each fed alternately with the antenna elements 9 in the respective other column, is greater than the horizontal distance between the remaining antenna elements, which are each arranged on one height line, in the adjacent columns. Once again, this makes it possible to also influence and vary the horizontal radiation spectrum. In the illustrated exemplary embodiment, the distance between the centers of the antenna elements which are arranged in the left-hand and right-hand columns is intrinsically about X/2, or is in this range. This means that the distance between the antenna elements in the left-hand and right-hand columns may, for example, be less than X/2 20%, or preferably less than 2/2 10%, with the distance between the centers of the two antenna elements 109a, 109b which are arranged in the center and are offset outwards now being, for example, in a range between X/2 and X. However, in this case as well, the distance may also be chosen to be considerably greater in order to achieve different beamforming widths.
One example of an antenna array having four columns, that is to say with the columns 5a, 5b, 5c and 5d, is shown in Figure 14. In particular, nine antenna elements are arranged in each column in this exemplary embodiment.

Normally, all of the antenna elements in one column are fed jointly. In the illustrated exemplary embodiment, however, the feeds have in each case been interchanged in pairs on a central height line in such a way that the antenna elements 9 which are intrinsically fed jointly in the left-hand column 5a are not fed together with the central antenna element 109b which is located in the left-hand column 5a, but with the antenna element 109a which is provided on the same height line in the second column 5b.

Conversely, the antenna elements 9 which are shown in a darkened form and are located in the second column are fed jointly, but not with the antenna element which is located in the center. This results in joint feeding together with the antenna element 109b which is arranged in the first column 5a.

The feeds in the third and fourth columns 5c, 5d are likewise interchanged. In this case as well, the antenna elements 9 which are shown in a lightened form in the column 5d are not fed together with the antenna element 109c which is arranged in the center in the same column, but together with the antenna element 109d which is arranged in the center of the third column 5c.
The antenna elements which are shown in a darkened form and are arranged in the third column Sc are then fed together with the antenna element unit 109c which is located in the center of the antenna array in the column 5d.

in this exemplary embodiment as well, further pairs of antenna elements on different height lines can likewise once again be fed in an interchanged form. Apart from this, all of the antenna elements which are shown in a lightened form in Figure 14 can also be fed jointly and, by way of example, all of the antenna elements which are shown in a darkened form can likewise be fed jointly.

In the exemplary embodiment as shown in Figure 14, as well, the distance between two horizontally adjacent antenna elements which are arranged in two different columns is preferably about X/2. This means that, in general, the distance between the horizontally adjacent antenna elements is X/2 less than 20% or less than 10% as a tolerance.

All of these measures allow beamforming within a column to be preset differently using very simple means. This is because a horizontal polar diagram of different width for one column of an antenna array such as this is produced as a function of whether in each case only some of the antenna elements provided in one column are fed jointly there, and whether and if yes, how many, further jointly fed antenna elements are arranged in another column.

Claims

WHAT IS CLAIMED IS:

1. A two-dimensional antenna array comprising:
at least two vertically oriented columns, at least one of said columns comprising at least two radiators or radiator groups arranged in a vertical direction and vertically offset with respect to each other;
at least one additional radiator or radiator group provided for said at least one column, said at least one additional radiator or radiator group being fed commonly with the radiators or radiator groups provided in said at least one column, the additionally provided at least one radiator or radiator group for said at least one column being arranged horizontally offset to the other radiators or radiator groups provided in said at least one column.

2. The antenna array as claimed in claim 1, wherein the at least one additionally provided radiator or radiator group is accommodated in an adjacent column.

3. The antenna array as claimed in claim 1, wherein the at least one additionally provided radiator or radiator group is arranged in a respective adjacent column between two neighboring radiators or radiator groups in a vertical direction.

4. The antenna array as claimed in claim 1, wherein the at least one additionally provided radiator or radiator group is placed on the vertical connecting line between the at least two radiators or radiator groups in said column.

5. The antenna array as claimed in claim 1, wherein the at least one additionally provided radiator or radiator group lies offset to the vertical connecting line between the at least two radiators or radiator groups in said column.

6. The antenna array as claimed in claim 1, wherein the radiators or radiator groups in a column lie vertically offset to those of an adjacent column by half the vertical spacing between two radiators or radiator groups placed vertically one above the other.

7. The antenna array as claimed in claim 1, wherein the radiator or radiator groups in a column lie at the same horizontal elevation as those in an adjacent column.

8. The antenna array as claimed in claim 1, wherein at least five radiators or radiator groups are arranged one above the other in the columns with vertical offset, and that the at least one additionally provided radiator or radiator groups are placed centrally or mostly centrally with respect to the entire vertical length of the antenna array.

9. The antenna array as claimed in claim 1, wherein at least five radiators or radiator groups are arranged one above the other in the columns with vertical offset, and that the at least one additionally provided radiator or radiator groups are placed at the upper or at the lower end of the antenna array.

10. The antenna array as claimed in claim 1, wherein the columns exhibit a spacing of 0.25 A to 1 A, where A is operating wavelength.

11. The antenna array as claimed in claim 1, wherein the vertical spacing of the radiators or radiator groups in said column, without taking into account additional radiators or radiator groups, lies between 0.7 A and 1.2 A, where A is mean operating wavelength.

12. The antenna array as claimed in claim 1, wherein the radiators or radiator groups are selected from the group comprising dipoles, cross dipoles, X-shaped radiating vector dipoles, linearly polarized radiators and patch radiators.

13. The antenna array as claimed in claim 1, wherein the radiators or radiator groups provided in a column and additional radiators or radiator groups in an associated column assigned to these radiators are fed with the same electrical phase.

14. The antenna array as claimed in claim 1, wherein the radiators or radiator groups provided in a column and additional radiators or radiator groups in an associated column assigned to these radiators are fed with varying electrical phase to alter the tracking behavior.

15. The antenna array as claimed in claim 1, wherein the individual columns can be adjusted electrically independently of one another, using phase shifters.

16. The antenna array as claimed in claim 1, wherein the individual columns can be commonly adjusted electrically, using coupled phase shifters.

17. The antenna array as claimed in claim 1, wherein in an adjustment of a down-tilt angle by the use of a varying phase-position feed for the various radiators arranged vertically one above the other, the additionally provided radiators are fed with a phase angle, which corresponds to that of the radiator provided in a column, which lies at the same height level, or lies at a vertical offset not greater than the spacing between two associated radiators arranged vertically one above the other in said column.

18. The antenna array as claimed in claim 1, wherein two additional radiators are fed with the same phase angle as a radiator in the associated column.

19. The antenna as claimed in claim 1, wherein in each column an odd number of radiators are provided, arranged vertically one above the other.

20. The antenna array as claimed in claim 19, wherein at least one radiator is provided in each column is fed commonly with two additional radiators provided in an adjacent column, with the same phase angle.

21. A two-dimensional antenna array comprising:
at least two columns running vertically, at least one column having at least two radiators or radiator groups arranged in a vertical direction with respect to each other;
the at least one column having at least two radiators or radiator groups vertically offset from one another;
at least one additional radiator group which is fed commonly with the radiators or radiator groups in said at least one column, the at least one additional radiator group for said at least one column arranged horizontally offset to the other radiators or radiator groups in the column.

22. A two-dimensional antenna array having plural vertically-oriented radiator columns, said array including at least one radiator column comprising:
a first set of vertically offset radiators; and a further set of radiators horizontally offset from said first radiator set;
wherein said first and further radiator sets are fed in common.

23. A two-dimensional antenna array defining at least two vertically running gaps, the antenna array comprising:
at least two radiators offset to one another in the vertical direction in at least one of said gaps, the radiators in said at least one gap except for at least one radiator being jointly fed, and said at least one radiator in at least one of said gaps being fed jointly with some but not all of the radiators of a gap adjacent to said at least one gap.

24. The antenna array as claimed in claim 23, wherein said jointly fed radiator is arranged such that the vertical distance is the same at a given horizontal offset.

25. The antenna array as claimed in claim 23, wherein said jointly fed radiator comprises plural radiators arranged offset to one another in the vertical direction such that the vertical distance is substantially the same between said plural radiators which are vertically offset to one another and/or are located horizontally at different heights.

26. The antenna array as claimed in claim 25, wherein the jointly fed radiator comprising plural radiators arranged offset to one another in the vertical direction such that the vertical distance is substantially the same between two radiators which are vertically offset to one another and/or the vertical distance of the radiators located horizontally at different heights.

27. The antenna array as claimed in claim 23, wherein the radiators are located in pairs on a common vertical line in at least two gaps.

28. The antenna array as claimed in claim 23, wherein the jointly fed radiator comprises plural radiators located at a regular vertical distance on top of one another including at least one radiator located with a horizontal offset to other jointly supplied radiators in a gap adjacent said at least one gap.

29. The antenna array as claimed in claim 23, defining at least two gaps, radiators within said at least two gaps being located at a regular vertical distance to one another and in the same vertical position in pairs, in said at least two gaps there being at least one pair of two radiators such that one radiator which is jointly supplied and located in the at least one gap is jointly supplied with at least one radiator of a gap adjacent thereto.

30. A two-dimensional antenna array comprising:

a structure defining at least first and second gaps extending vertically when the antenna is in use;
plural radiators disposed at least partially within said first gap, said plural radiators being offset from one another in the vertical direction; and at least one radiator at least partially disposed within said second gap, wherein at least one of said plural radiators within said first gap and said at least one radiator but not all of the radiators within said second gap are jointly fed.

31. A two-dimensional antenna array comprising:
a structure defining at least first and second columns extending vertically when the antenna is in use;
plural radiators disposed at least partially between said first column and said second column, said plural radiators being offset from one another in the vertical direction; and at least one further radiator at least partially disposed outside of a space between said first column and said second column, wherein at least one of said plural radiators and said at least one further radiator but not all of the further radiators are jointly fed.

32. The two-dimensional antenna array of claim 23 wherein said antenna array operates on only one band.

33. The two-dimensional antenna array of claim 30 wherein said antenna array operates on only one band.

34. The two-dimensional antenna array of claim 31 wherein said antenna array operates on only one band.