BACKGROUND TO THE INVENTION The development of mobile telephony has created a need for simple and inexpensive mass production of antennas for, inter alia, base stations. In order to achieve better and more reliable coverage, which is of particular importance within mobile telephony, use is advantageously made of polarization diversity. Two different polarizations, usually at right angles to one another, are used, preferably via one and the same antenna. It is important that the two polarizations in dual-polarized antennas have antenna patterns which are as equivalent as possible and that each polarization vector maintains its direction for all azimuth angles.

Mobile telephony utilizes frequency ranges which lie within the microwave range, for which reason an antenna which is often used is the microstrip antenna. Like some other microwave antennas, microstrip antennas comprise radiating antenna elements which are mounted in front of

a ground plane. Dual-polarized antennas commonly found within, for example, mobile telephony are polarized using 0/90° or +45". Dual-polarized antennas exist in two basic variants, the first of which comprises two different types of single-polarized antenna elements in order to produce the two different polarizations, and the second comprises dual-polarized antenna elements instead. Both variants of dual-polarized antennas have advantages and disadvantages. The use of antennas, in particular microwave antennas, with dual-polarized radiation elements reduces the size and production costs of the antenna compared with the use of single-polarized radiation elements. A requirement has arisen, in particular within mobile telephony, for antennas with +45° polarization because this type of polarization appears for the time being to have many advantages, such as more symmetrical propagation/attenuation, compared with 0/90° polarization.

Irrespective of the type of dual-polarized antenna used, it is important, as mentioned above, that the two polarizations have antenna patterns which are as equivalent as possible. In antennas of the type comprising radiating antenna elements in front of a ground plane, the extent of the ground plane is of great importance for the antenna patterns. Owing to, inter alia, production reasons, assembly reasons and the possibility of having a distribution network of, for example, the microstrip type for the radiating antenna elements, it is desirable and sometimes necessary to maintain a rectangular ground plane of a certain size.

A base station usually uses a number of antennas in order to cover a cell. Different mobile telephony operators make use of different algorithms for cell planning, which results in a demand for antennas with, inter alia, different lobe widths. One known way of controlling the lobe width of an antenna with radiating antenna elements mounted in front of a ground plane, such as microstrip

antennas, is to modify the dimensions of the ground plane. If a large lobe width is desired, the size of the ground plane is limited. A major disadvantage of the size of the ground plane being reduced in the case of a large lobe width being desired is that this also limits the possibility of, for example, using a microstrip distribution network as a feeder network for the radiating elements. Therefore, antennas with wide lobes cannot on the whole use microstrip distribution networks as feeder networks or they can use them only to an extremely limited extent. If desired, antennas with narrow lobes can in most cases use microstrip distribution networks as feeder networks, which is advantageous as far as, inter alia, manufacturing aspects and therefore the costs of these antennas are concerned.

Another major disadvantage of modifying the size of the ground plane in order to control the lobe width is that the shape and size of the antenna are influenced, that is to say that different antenna dimensions must be calculated and subsequently manufactured for different desired lobe widths. Modifying the size and shape of an antenna results in a number of consequential problems such as, for example, the need for different weather protection (radomes) and modified fixing/mounting arrangements.

SUMMARY OF THE INVENTION One object of the invention is to indicate a device for and/or comprised in antennas, in particular dual- polarized microwave antennas, for which equivalent antenna patterns can be obtained for the different polarizations without modifying the size of the ground plane of the antenna.

A further object of the invention is to indicate a device for and/or comprised in antennas, in particular dual- polarized microwave antennas such as microstrip antennas,

for controlling the lobe width and if appropriate the direction of the antenna without having to modify the size of the ground plane of the antenna.

According to the invention, the abovementioned objects are achieved by a device for and/or comprised in antennas, in particular dual-polarized microwave antennas, for which equivalent antenna patterns can be obtained for the different polarizations without modifying the size of the ground plane of the antenna.

Antenna lobe shape-adjusting part-elements in a part- element pair are positioned on either side of the radiating antenna elements for each polarization. The shape and positioning of the antenna lobe shape-adjusting part-elements around the antenna elements also controls the antenna lobes. In this way, the antenna lobes can be controlled in the desired manner so that equivalent antenna patterns can be obtained for the two polarizations irrespective of the size of the ground plane of the antenna, the size of which depends, for example, on a desired microstrip distribution network for the antenna.

According to the invention, the abovementioned objects are also achieved by means of a dual-polarized antenna for receiving and transmitting electromagnetic signals mainly within the microwave frequency range. The antenna has a normal and an antenna lobe with a first lobe direction relative to the normal of the antenna and a first lobe width for a first polarization and a second lobe direction relative to the normal of the antenna and a second lobe width for a second polarization. The antenna also has a ground plane and at least one first and one second antenna element. The ground plane has a first side and a second side. The antenna elements are arranged at a predefined distance from the first side of the ground plane along a first line, and are fed by feed means from the second side of the ground plane. The antenna comprises at least one pair of antenna lobe

shape-adjusting part-elements where each antenna lobe shape-adjusting part-element has a height along the normal of the antenna and a longitudinal extent. One antenna lobe shape-adjusting part-element of each pair is arranged on either side of a respective antenna element.

Each antenna lobe shape-adjusting part-element pair is arranged in relation to the ground plane relative to a respective antenna element in such a manner that the lobe direction and the lobe width for mainly one polarization in the respective antenna element can be determined.

Each antenna lobe shape-adjusting part-element pair is suitably arranged in relation to the respective antenna element in such a manner that the first and second lobe directions are mainly the same and that the first and second lobe widths are mainly the same in terms of size.

The antenna elements may also suitably be centered along the first line. In one embodiment, the antenna elements can be aperture-coupled patches. The antenna elements may also suitably be slots, dipoles or any other suitable antenna element.

The antenna lobe shape-adjusting part-elements can mainly be designed as wall elements, the longitudinal extents of which are mainly parallel to the first line in certain embodiments. The antenna lobe shape-adjusting part- elements may be electrically isolated from the ground plane or electrically interconnected with the ground plane.

According to the invention, the lobe directions and the lobe widths can be controlled in a number of different ways. The height of the antenna lobe shape-adjusting part-elements can be varied and/or their distance from the respective antenna element can be varied. The angle of the antenna lobe shape-adjusting part-elements relative to the normal of the antenna can also be varied.

An arbitrary combination of these methods may of course be used in order to control the lobe directions and the

lobe widths.

The antenna can be of a type with single-polarized antenna elements. The antenna lobe shape-adjusting part- elements for the respective antenna element for the first polarization then suitably have a longitudinal extent which is mainly at right angles to the first polarization. The antenna lobe shape-adjusting part- elements for the respective antenna element for the second polarization can suitably have a longitudinal extent which is mainly parallel to the second polarization. In certain applications, it may be suitable for the antenna elements for the second polarization not to have antenna lobe shape-adjusting part-element pairs.

In certain other applications, it may be suitable for the antenna elements for the first polarization not to have antenna lobe shape-adjusting part-element pairs.

The antenna may in certain applications be a variant in which the antenna elements are dual-polarized antenna elements. It is then suitable for a first or a first set of antenna lobe shape-adjusting part-element pair(s) to have a longitudinal extent which is mainly parallel to the first polarization and at right angles to the second polarization. In the event that the antenna comprises a second or a second set of antenna lobe shape-adjusting part-element pair(s), it is suitable that they have a longitudinal extent which is mainly parallel to the second polarization and at right angles to the first polarization.

In certain applications, the antenna lobe shape-adjusting part-elements suitably have a longitudinal extent which mainly corresponds to the length of that side of the corresponding antenna element to which the antenna lobe shape-adjusting part-element is mainly parallel.

In certain embodiments, antenna lobe shape-adjusting part-elements for one polarization may suitably be

interconnected along each side of the first line. Antenna lobe shape-adjusting part-elements arranged along the same side of the first line may be interconnected in certain cases. The antenna lobe shape-adjusting part- elements on both sides of the first line may be interconnected in such a manner that a line is formed around all the antenna elements of the antenna. In such cases, it may be suitable for the antenna lobe shape- adjusting part-elements to be varied only in height in order to control the lobe directions and the lobe widths.

As an alternative or in combination, the antenna lobe shape-adjusting part-elements may vary only in distance from the respective antenna element in order to control the lobe directions and the lobe widths.

At least one pair of the antenna lobe shape-adjusting part-elements may be arranged symmetrically in relation to the respective antenna element. All the pairs of antenna lobe shape-adjusting part-elements for a first polarization may also be arranged symmetrically in relation to the respective antenna element. Or even all the antenna lobe shape-adjusting part-elements may be arranged symmetrically in relation to the respective antenna element.

As an alternative or in combination, at least one pair of the antenna lobe shape-adjusting part-elements may be arranged asymmetrically in relation to the respective antenna element. All the pairs of antenna lobe shape- adjusting part-elements for a first polarization may also be arranged asymmetrically in relation to the respective antenna element. Or even all the antenna lobe shape- adjusting part-elements may be arranged asymmetrically in relation to the respective antenna element.

In preferred embodiments of the invention, no antenna lobe shape-adjusting part-element crosses the first line so as not to isolate any antenna element along the first line from another antenna element along the first line

with the antenna lobe shape-adjusting part-elements.

In certain embodiments of the invention, each antenna lobe shape-adjusting part-element may comprise a first and a second side which are interconnected along an edge.

The edges are not that part of the antenna lobe shape- adjusting part-elements which is arranged closest to the ground plane. First angles are formed at the edges between the first sides of the antenna lobe shape- adjusting part-elements and the normal of the first side of the ground plane through the edges. The first angles are considered positive from the normal of the first side of the ground plane through the edges and away from the antenna elements. The first angles are suitably greater than zero in order thus to control the antenna lobe.

Second angles may also be formed at the edges between the second sides of the antenna lobe shape-adjusting part- elements and the normal of the first side of the ground plane through the edges. The second angles are considered positive from the normal of the first side of the ground plane through the edges and towards the antenna elements.

The second angles may suitably be greater than zero in order thus to control the antenna lobe.

In other embodiments of the invention, each antenna lobe shape-adjusting part-element has a first and a second side which are interconnected along an edge. The edges are not that part of the antenna lobe shape-adjusting part-elements which is arranged closest to the ground plane. A first angle is formed at the edge between the first sides of the antenna lobe shape-adjusting part- elements and the normal of the first side of the ground plane through the edge. The first angles are considered positive from the normal of the first side of the ground plane through the edges and away from the antenna elements. Second angles are formed at the edges between the second respective sides of the antenna lobe shape- adjusting part-elements and the normal of the first side of the ground plane through the edges. The second angles

are considered positive from the normal of the first side of the ground plane through the edges and towards the antenna elements. The first angles are suitably greater than zero and the second angles are suitably negative with an absolute value which is smaller than that of the first angles, in order thus to control the antenna lobe.

In a further embodiment, each antenna lobe shape- adjusting part-element has a first and a second side which are interconnected along an edge. The edges are not that part of the antenna lobe shape-adjusting part- elements which is arranged closest to the ground plane.

First angles are formed at the edges between the first sides of the antenna lobe shape-adjusting part-elements and the normal of the first side of the ground plane through the edges. The first angles are considered positive from the normal of the first side of the ground plane through the edges and away from the antenna elements. Second angles are formed at the edges between the second sides of the antenna lobe shape-adjusting part-elements and the normal of the first side of the ground plane through the edges. The second angles are considered positive from the normal of the first side of the ground plane through the edges and towards the antenna elements. The second angles are suitably greater than zero and the first angles are suitably negative with an absolute value which is smaller than that of the second angles, in order thus to control the antenna lobe.

The edges may lie between the ground plane and a parallel plane in which the antenna elements mainly lie. The edges may also mainly lie in a plane in which the antenna elements lie and which is parallel to the ground plane.

Alternatively, the edges may also lie beyond a plane in which the antenna elements lie, in relation to the parallel ground plane.

The abovementioned objects are achieved by the invention also by means of a dual-polarized antenna for receiving

and transmitting electromagnetic signals mainly within the microwave frequency range. The antenna has a normal and an antenna lobe. The antenna lobe has a first lobe direction relative to the normal of the antenna with a first lobe width for a first polarization and the antenna lobe also has a second lobe direction relative to the normal of the antenna with a second lobe width for a second polarization. The antenna also comprises a ground plane and at least one dual-polarized antenna element.

The ground plane comprises a first side and a second side. The antenna elements of the antenna are arranged, centered along a first line, at a predefined distance from the first side of the ground plane and the antenna elements of the antenna are fed by feed means from the second side of the ground plane. The antenna comprises at least one first pair of antenna lobe shape-adjusting part-elements for each antenna element. Each antenna lobe shape-adjusting part-element has a height along the normal of the antenna and a longitudinal extent. The first antenna lobe shape-adjusting part-element pair for each antenna element has mainly a longitudinal extent which is parallel to the first polarization and at right angles to the second polarization. One antenna lobe shape-adjusting part-element of each pair is arranged on either side of a respective antenna element. Each antenna lobe shape-adjusting part-element pair is arranged in relation to the ground plane relative to a respective antenna element in such a manner that the first and second lobe directions are mainly the same and that the first and the second lobe widths are mainly the same in terms of value.

The antenna may suitably comprise a second antenna lobe shape-adjusting part-element pair for each antenna element. The second antenna lobe shape-adjusting part- element pair for each antenna element has a longitudinal extent which is mainly parallel to the second polarization and at right angles to the first polarization.

In certain embodiments, it is suitable that the antenna comprises at least two dual-polarized antenna elements and that no antenna lobe shape-adjusting part-element crosses the first line so as not to isolate any antenna element along the first line from another antenna element along the first line with the antenna lobe shape- adjusting part-elements.

The abovementioned objects are achieved by the invention also by means of a dual-polarized antenna for receiving and transmitting electromagnetic signals mainly within the microwave frequency range. The antenna comprises a normal and an antenna lobe. The antenna lobe has a first lobe direction relative to the normal of the antenna with a first lobe width for a first polarization and the antenna lobe has a second lobe direction relative to the normal of the antenna with a second lobe width for a second polarization. The antenna comprises a ground plane and at least one first single-polarized antenna element for the first polarization and at least one second antenna element for the second polarization. The ground plane comprises a first side and a second side. The antenna elements are arranged, centered along a first line, at a predefined distance from the first side of the ground plane and the antenna elements are fed by feed means from the second side of the ground plane. The antenna comprises a first pair of antenna lobe shape- adjusting part-elements for each first antenna element for the first polarization. Each antenna lobe shape- adjusting part-element has a height along the normal of the antenna and a longitudinal extent which is mainly at right angles to the first polarization. One antenna lobe shape-adjusting part-element of each pair is arranged on either side of a respective antenna element. Each first antenna lobe shape-adjusting part-element pair is arranged in relation to the ground plane relative to a respective antenna element in such a manner that the first and second lobe directions are mainly the same and that the first and the second lobe widths are mainly the

same in terms of value.

The antenna may suitably comprise a second pair of antenna lobe shape-adjusting part-elements for each second antenna element for the second polarization. Each antenna lobe shape-adjusting part-element has a height along the normal of the antenna and a longitudinal extent which is mainly parallel to the second polarization. One antenna lobe shape-adjusting part-element of each pair is arranged on either side of a respective second antenna element. Each first and second antenna lobe shape- adjusting part-element pair is arranged in relation to the ground plane relative to a respective antenna element in such a manner that the first and second lobe directions are mainly the same and that the first and the second lobe widths are mainly the same in terms of value.

Alternatively, the second antenna elements for the second polarization may not have antenna lobe shape-adjusting part-element pairs.

It is suitable that none of the antenna lobe shape- adjusting part-elements crosses the first line so as not to isolate any antenna element along the first line from another antenna element along the first line with the antenna lobe shape-adjusting part-elements.

The invention has a number of advantages compared with the prior art as far as antennas are concerned, and in particular dual-polarized microwave antennas such as, for example, dual-polarized microstrip antennas which use microstrip distribution networks as feeder networks for the radiating elements of the antenna. The radiating elements of the antenna may be, for example, slots, aperture-coupled patches or dipoles. According to the invention, the lobe width (the lobe size) is controlled individually for each polarization by varying only the inclination, the height or the position (or a combination of these) of the antenna lobe shape-adjusting part-

elements which are positioned in relation to those sides of the radiating antenna elements which do not face another radiating antenna element in the same column. In this way, correspondence between the antenna patterns for the two polarizations can be obtained. The invention also controls the direction of the antenna lobe in relation to the normal of the antenna by defining the centering of the antenna element in relation to the antenna lobe shape-adjusting part-elements or by means of different heights and angles of the antenna lobe shape-adjusting part-elements on opposite sides of the radiating antenna elements. In this way, an antenna can be designed and subsequently manufactured in large series and can then, depending on demand, be customized simply with regard to, inter alia, the lobe width at a late stage of production.

The invention also eliminates partially or completely cross-coupling between polarizations in dual-polarized radiation elements. This is achieved by the invention creating a mirror-symmetrical environment for each polarization direction, the result of which is that no component in the other polarization can be excited. In this way, the use of microstrip antennas with +45" dual- polarized radiating antenna elements is made possible.

According to the invention, cross-coupling is also reduced between different dual-polarized antenna elements in an array antenna. This means that the invention is of interest with regard to, for example, base station antennas for mobile telephone systems, which are manufactured in great quantities.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in greater detail below in a non-limiting manner for the purpose of clarification, with reference to the attached drawings, in which Fig. 1 shows a front view of a first embodiment of a

0/90° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled single-polarized patches, Fig. 2 shows a side view of the antenna in Figure 1, Fig. 3 shows a front view of a second embodiment of a 0/90° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled single-polarized patches, Figs 4A-E show end views of different embodiments of antennas, for example of the antennas in Figures 1 and 3, according to the invention, Fig. 5 shows a front view of a third embodiment of a 0/90° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled single-polarized patches, Fig. 6 shows a front view of a +45° dual-polarized vertical one-dimensional array antenna according to the invention with aperture- coupled dual-polarized patches, and Figs 7A-E show cross-sections of different embodiments of antennas according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS In order to illustrate the invention, a few examples of its application are to be described in the following with reference to Figures 1 to 7.

Figure 1 shows a front view of an array antenna designed according to the invention. The array antenna in Figure 1 is a 0/90° dual-polarized vertical one-dimensional array antenna which may suitably be used as a base

station antenna in a mobile telephone system. In this example, aperture-coupled single-polarized patches 151, 153 are used as radiating antenna elements. The patches 151, 153 are supported by, for example, a patch-support substrate 141 above, for example, slots in a ground plane 190. According to the invention, uniform antenna patterns can be obtained for the two polarizations by virtue of the fact that the antenna elements 151, 153 have antenna lobe shape-adjusting part-elements 101, 102, 103, 104 made of an electrically conductive material such as copper which are positioned on each side of the respective antenna element on top of the ground plane 190. A first type of single-polarized antenna element 151 for a first polarization has a first antenna lobe shape- adjusting part-element 101 arranged on one side and a second antenna lobe shape-adjusting part-element 102 arranged on the other side. The longitudinal directions of the two antenna lobe shape-adjusting part-elements 101, 102 are mainly at right angles to the first polarization. Two antenna lobe shape-adjusting part- elements 101, 102 for an antenna element 151 form an antenna lobe shape-adjusting part-element pair. If appropriate, a second type of single-polarized antenna element 153 for a second polarization also has a first antenna lobe shape-adjusting part-element 103 arranged on one side and a second antenna lobe shape-adjusting part- element 104 arranged on the other side. The longitudinal directions of the two antenna lobe shape-adjusting part- elements 103, 104 are mainly parallel to the second polarization. In this first embodiment, the antenna lobe shape-adjusting part-elements 101, 102, 103, 104 are suitably designed as wall elements which have a longitudinal direction mainly parallel to the sides of the antenna element alongside which they are positioned, with a length which mainly corresponds to the length of the side of the respective antenna element. The shape and the positioning of the antenna lobe shape-adjusting part- elements in relation to the respective antenna element determines the antenna pattern of the respective antenna

element. The edges of the patches 151, 153 suitably lie in the order of A/20 to A/2 (where A is the wavelength) from the antenna lobe shape-adjusting part-elements 101, 102, 103, 104. The antenna lobe shape-adjusting part- elements 101, 102, 103, 104 may either be electrically connected to the ground plane 190 or electrically isolated from the ground plane 190, depending on the desired antenna characteristics.

Figure 2 shows a side view of an antenna designed according to the invention, for example a side view of the microstrip antenna according to the invention shown in Figure 1. Here, the antenna lobe shape-adjusting part- elements 201, 203 are shown from the side. The antenna lobe shape-adjusting part-elements 201, 203 are arranged on the ground plane 290 which is shown here with its substrate 292. In this exemplary embodiment, the antenna lobe shape-adjusting part-elements are higher above the ground plane than the radiating antenna elements are (in this case aperture-coupled patches arranged on a support substrate 241).

Figure 3 shows a front view of a second embodiment of a 0/90° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled single-polarized patches. As in Figure 1, the antenna comprises radiating antenna elements 351 for a first polarization and radiating antenna elements 353 for a second polarization which are arranged in relation to a ground plane 390. In this example, as in that in Figure 1, the radiating antenna elements are aperture-coupled patches 351, 353 mounted on a support substrate 341. The antenna lobe shape-adjusting part-elements 301 for a first polarization correspond to those in Figure 1. The antenna lobe shape-adjusting part-element pair 305 for a second polarization extend along the entire antenna. The individual antenna lobe shape-adjusting part-elements 103 and 104 according to Figure 1 are interconnected and thus form the antenna lobe shape-adjusting part-element pair

305 for the second polarization. As long as the radiating antenna elements 351 for the first polarization do not "see" the antenna lobe shape-adjusting part-element pair 305 for the second polarization over their own respective antenna lobe shape-adjusting part-element pair 301 for the first polarization, the extension behind the antenna lobe shape-adjusting part-elements 301 will have only a minimal effect on functioning. The whole of the antenna lobe shape-adjusting part-elements 305 for the second polarization may be designed as walls or may be an edge which has another function, for example as a fixing/- mounting arrangement for the ground plane 390 and its substrate. In certain applications, it may even be adequate to have only the antenna lobe shape-adjusting part-elements 301 for the first polarization.

Figures 4A-E show end views of different embodiments of antennas, for example end views of the antennas in Figures 1 and 3, according to the invention. As an illustration of radiating antenna elements, aperture- coupled patches 450 are shown here also above a ground plane 490 and a ground plane support/substrate 492. The figures show a possible way of manufacturing and embodying the antenna lobe shape-adjusting part-elements in the form of two punched out/milled out U-profiles, and also different embodiments for the antenna lobe shape- adjusting part-elements per se and in relation to the radiating elements. It is common to all the embodiments according to Figures 4A-E that the part-element 401 of the antenna lobe shape-adjusting part-element pair 401, 402 for a first polarization on a first side of the radiating antenna elements 450 is interconnected with a bottom 408 in the direction towards the ground plane 490.

The bottom 408 is in turn interconnected with part- element 403 of the antenna lobe shape-adjusting part- element pair 403, 404 for a second polarization on the first side of the radiating antenna elements 450. In this end view, these three segments (the part-elements 401 for a first polarization, the bottom 408 and the part-

elements 403 for a second polarization) form the shape of a U with its bottom 408 in the direction towards the ground plane. A U is also formed on the second side of the radiating antenna elements 450 in a corresponding manner by the part-elements 402 for a first polarization, the bottom 408 and the part-elements 404 for a second polarization. These U:s can be made from U-profiles which are milled out or punched out on the sides (or only one side, the one towards the radiating antenna elements in accordance with the embodiment according to Figure 3) in order thus to form the antenna lobe shape-adjusting part- elements 401, 402, 403, 404. The U-shape can also be made from a plane piece which is punched/milled and then bent in order to obtain the correct shape. Depending on whether the antenna lobe shape-adjusting part-elements 401, 402, 403, 404 are to be electrically interconnected with the ground plane or not (which in turn depends on the desired antenna characteristics), the U-shape may be soldered, screwed, riveted, or taped with double-sided or single-sided insulating or electrically conductive tape to the ground plane.

Figure 4A shows an end view of a vertical one-dimensional dual-polarized antenna according to the invention with a first 401, 402 and a second antenna lobe shape-adjusting part-element pair arranged symmetrically on both sides of the radiating antenna elements 450. This embodiment shows all the antenna lobe shape-adjusting part-elements 401, 402, 403, 404 with the same height.

Figure 4B also shows an embodiment with all the antenna lobe shape-adjusting part-element pair 401, 402, 403, 404 arranged symmetrically on both sides of the radiating antenna elements 450 but with different mutual distances to those in Figure 4A. This embodiment shows how the antenna lobe shape-adjusting part-element pair 401, 402 for a first polarization are not as tall as the antenna lobe shape-adjusting part-element pair 403, 404 for a second polarization.

Figure 4C shows an embodiment in which the heights of the antenna lobe shape-adjusting part-element pairs 401, 402, 403, 404 for a first and a second polarization have the opposite relationship with one another. The embodiment shows all the antenna lobe shape-adjusting part-element pairs 401, 402, 403, 404 arranged symmetrically on both sides of the radiating antenna elements 450 but with different mutual distances in relation to those in Figures 4A and 4B.

Figure 4D shows how the antenna lobe shape-adjusting part-elements 401, 402, 403, 404 may be inclined at an angle 421, 422, 423, 424 on the ground plane 490 relative to the normal 480 of the antenna/ground plane. The angles 421, 422, 423, 424 may be all the same or all different or all the same in pairs, depending entirely on the desired characteristics.

Figure 4E shows how the antenna lobe shape-adjusting part-elements 401, 402, 403, 404 are arranged asymmetrically on the different sides of the radiating antenna elements. Arranging the antenna lobe shape- adjusting part-elements 401, 402, 403, 404 asymmetrically is a method of, according to the invention, controlling the direction of the resulting antenna lobe in a direction other than the normal of the antenna. Asymmetry can also be achieved by means of different heights of the various part-elements 401, 402, 403, 404, different angles, different distances between the part-elements 401, 402 for a first polarization and the part-elements 403, 404 for a second polarization on the different sides of the radiating antenna elements 450. The desired characteristics can of course be obtained by means of an arbitrary combination of these methods.

Figure 5 shows a front view of a third embodiment of a 0/90° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled single-polarized patches 551, 553 as the radiating

antenna elements on a support substrate 541 above a ground plane 590. The antenna lobe shape-adjusting part- elements 506 for a first polarization are in this embodiment interconnected on the same side of the radiating antenna elements 551, 553 with the antenna lobe shape-adjusting part-elements 507 for a second polarization by means of interconnecting elements 531, 533. The part-elements 506, 507 thus form continuous walls along both sides of the radiating antenna elements 551, 553. The interconnecting elements 531, 533 are shown in the figure as oblique but, depending on the length of the part-elements 507, 506 and their positioning on the ground plane 590, these interconnecting elements 531, 533 may be vertical, horizontal or have any other angle. If appropriate, these continuous walls are interconnected with end elements 535, 537. These end elements 535, 537 interconnect the walls only above and below the radiating antenna elements 551, 553 in such a manner that a continuous wall or frame is formed around all the radiating antenna elements 551, 553 in the vertical one- dimensional antenna concerned.

Figure 6 shows a front view of a +45° dual-polarized vertical one-dimensional array antenna according to the invention with aperture-coupled dual-polarized patches 659 as the radiating antenna elements on a support substrate 641 above a ground plane 690. This embodiment of the invention comprises antenna lobe shape-adjusting part-elements 611, 612 for a first polarization which are arranged across the radiating antenna elements 659 and antenna lobe shape-adjusting part-elements 613, 614 for a second polarization which are also arranged across the radiating antenna elements 659. The major difference between this embodiment and those described previously is that the antenna lobe shape-adjusting part-element pairs for the first and for the second polarization are arranged orthogonally with respect to one another along the radiating antenna elements 659. As in the embodiment according to Figure 5, the part-elements 611, 612, 613,

614 form walls along the antenna elements 659 on the respective side of the radiating antenna elements 659.

These walls may be interconnected in such a manner that the walls form a frame around all the radiating antenna elements 659 concerned.

Figures 7A to 7E show cross-sections of different embodiments of an antenna according to the invention. The cross-sections may, for example, be of an antenna according to Figure 1, 3, 5 or 6. The radiating antenna elements are here also illustrated as aperture-coupled patches 750 which are thus positioned a little way away from a ground plane 790. Only the ground planes 790 are shown with substrates 792. Figure 7A shows an antenna lobe shape-adjusting part-element 709 with a first side 730 angled away from the radiating antenna element 750 with the angle 726 between the side and the normal 775 (which in this case is the same as the second side 772 of the antenna lobe shape-adjusting part-element) of the ground plane, which normal passes through the upper edge 773 of the antenna lobe shape-adjusting part-element. The angle 725, 726 (-90° < angle 725, 726 < 1800) is a parameter which determines the lobe width (within the range 90" to 00 the lobe is widened and from 90" upwards <BR> <BR> <BR> the lobe is compressed) and has been shown as O" 0° in Figures 1, 3, 5 and 6. The cavity 778 which arises when the angle 725, 726 is greater than zero may be air, a support substrate or any other dielectric. The antenna lobe shape-adjusting part-element 709 may also be made entirely of metal which means that the cavity 778 is filled with metal.

Figure 7B shows the antenna lobe shape-adjusting part- element 709 with a height which is smaller than the distance between the ground plane 790 and the patch 750, that is to say that the upper edge 773 of the antenna lobe shape-adjusting part-element 709 lies between the ground plane 790 and a plane which is parallel to the ground plane and in which the radiating antenna element,

the patch 750, mainly lies.

Figure 7C shows the antenna lobe shape-adjusting part- element pair 709 with a height which is greater than the distance between the ground plane 790 and the patch 750.

Figures 7A, 7D and 7E show the antenna lobe shape- adjusting part-element pair 709 with such a height that the upper edges 773 of the antenna lobe shape-adjusting part-element pairs 709 mainly lie in the same plane as that in which the patch 750 is positioned. A taller antenna lobe shape-adjusting part-element pair gives a wider antenna lobe. The antenna lobe shape-adjusting part-elements 709 may be asymmetrical in height on the different sides of the patch 750. The antenna lobe will then be directed in the direction towards the antenna lobe shape-adjusting part-element which is the tallest.

According to the invention, the antenna lobe can also be controlled by the antenna lobe shape-adjusting part- elements 709 being positioned asymmetrically around the antenna element, in this example the patch 750, that is to say that one antenna lobe shape-adjusting part-element is closer to the antenna element than the other. The antenna lobe is turned in the direction in which the antenna element is positioned closest to the antenna lobe shape-adjusting part-element. The antenna lobe can also be controlled by modifying the distance of the antenna lobe shape-adjusting part-elements from the antenna element and a wider/larger antenna lobe is obtained the closer they are to the antenna element.

Figure 7D shows that an angle 727, 728 (-180° < angle 727, 728 < 90°), in this case shown as greater than 0°, between that side of the antenna lobe shape-adjusting part-element towards the patch 750 and the normal 775 of the ground plane/antenna, which normal passes through the upper edge 773 of the antenna lobe shape-adjusting part- element, may also be used for controlling the lobe (it is also possible, of course, that the angle 727, 728 may be negative with an absolute value which is less than the

angle 725, 726).

Figure 7E shows a further embodiment.

The invention relates to antennas, and in particular dual-polarized microwave antennas with radiating antenna elements above a ground plane such as microstrip antennas, and an adjustment of the shape of the different antenna lobes for the different polarizations in order to achieve a balance between them. The invention also relates to controlling the antenna lobes of the two polarizations and thus control of the direction of the antenna. It has been shown above how antenna lobe shape- adjusting part-element pairs positioned on the ground plane of the antenna in relation to at least one polarization and relative to radiating antenna elements for this polarization can, by means of the positioning and shape of the antenna lobe shape-adjusting part- elements, achieve symmetry between the antenna patterns of the two polarizations.

The invention is not limited to the embodiments indicated above but can be modified within the scope of the patent claims which follow.