CN118369820A - Antenna device with two stacked radiating elements - Google Patents

Abstract

The present disclosure relates to an antenna device for use in a base station, for example. The antenna device comprises two radiating elements arranged on a common axis, e.g. stacked on top of each other. Each radiating element is for radiating radio waves in response to an RF signal fed to the corresponding radiating element. The antenna device comprises a feeding structure for feeding the RF signal to the two radiating elements. The feed structure comprises a redirecting device for redirecting power between two or more branches, the redirecting device being for distributing power of the RF signal between the two radiating elements. The feed structure further comprises an inverter for setting a quasi-inverting phase between the RF signals at the two radiating elements to a first phase difference.

Description

Antenna device with two stacked radiating elements

Technical Field

The present disclosure relates to an antenna device for use in a base station, for example. The antenna device may be referred to as a multi-layer antenna device because the antenna device comprises two radiating elements arranged on a common axis, e.g. stacked on top of each other. The antenna device is designed to have high radiation directivity. The present disclosure also relates to a method for operating the antenna device.

Background

With Long-Term Evolution (LTE) deployment approaching completion, operators are preparing for the upcoming fifth generation (5 ^th generation, 5G) mobile network. One key technology for implementing this new generation of mobile communications is large-scale multiple-input multiple-output below 6GHz (massive multiple input multiple output, mMIMO). Thus, there is a need for a new antenna device that can integrate mMIMO with passive antenna arrays.

However, there are some limitations in deploying new antenna devices. For example, many national/regional regulations (especially europe) are a real limiting factor when new services and infrastructure are introduced, and the speed of propulsion may be slower than the speed of antenna technology development. Thus, to facilitate access to the antenna site while also complying with local regulations regarding antenna site upgrades, the size of any new antenna device should be comparable to the size of a conventional antenna device.

Furthermore, in order to be able to maintain the mechanical support structures already present at most antenna sites, the wind load (wind load) of any new antenna device should be comparable or equivalent to the currently installed antenna devices. These factors place very stringent constraints on the width of any new antenna device.

But the width of the antenna device also affects its radiation directivity. In particular, the radiation directivity of the antenna device is limited by its aperture and thus also by its width. This effect becomes particularly critical when multiple antenna arrays are placed in the same housing of the antenna device. It is well known that when a plurality of dipoles are placed side by side on a small reflector of an antenna device, the horizontal beam width (horizontal beam width, HBW) of the antenna device increases, thereby reducing the radiation directivity.

Some exemplary methods of solving this problem of reduced radiation directivity attempt to meet the HBW using a 90 ° mixer. The mixer would increase the radiation directivity by a small margin but would not fully exploit the HBW reduction, as it would produce side lobes from the main notch. Some other exemplary approaches to try to solve the problem of reduced radiation directivity may result in an increased depth (or thickness), reduced gain or reduced bandwidth of the antenna device.

In another approach, one or more end-fire arrays are arranged in a direction perpendicular to the normal of the reflector in order to form an improved radiation directivity antenna device. However, this approach can still be improved because the implementation of an antenna device with two layers of radiating elements has some drawbacks: first, a longer electrical length feed network may cause resonance, which may limit the operating bandwidth of the antenna device; secondly, the rotating balun feed structure by the upper and lower radiating elements introduces a 180 ° phase difference, which can lead to large size, high cost and difficult production of the balun; third, the method is based on larger heat sink sizes.

Disclosure of Invention

In view of the above, it is an object of the present disclosure to provide an antenna device that may have a width that complies with regulations and that may be used with existing support structures at antenna sites. In particular, it is an object of the present disclosure to ensure that the radiation directivity of the antenna device is high and not significantly reduced compared to conventional antenna devices having a large width. Therefore, the HBW of the antenna device does not significantly increase.

These and other objects are achieved by the subject matter of the independent claims. Advantageous implementations are further defined in the dependent claims.

A first aspect of the present disclosure provides an antenna apparatus comprising: a first radiating element and a second radiating element disposed on a common axis, each radiating element for radiating radio waves in response to a Radio Frequency (RF) signal fed to the respective radiating element; a feeding structure for feeding the RF signal to the first and second radiating elements; the feed structure comprises a redirecting device for redirecting power between two or more branches, the redirecting device for distributing power of the RF signal between the first radiating element and the second radiating element; the feed structure comprises an inverter for setting a quasi-inverted phase (quasi-INVERTED PHASE) between the RF signal at the first radiating element and the RF signal at the second radiating element to a first phase difference.

By setting the first phase difference between the two radiating elements, a combined radiation pattern may be achieved that is more directional than the radio waves of a simple/single radiating element.

The result may be a significant increase in the directivity of the combined radiation pattern of the antenna device. This may miniaturize the reflector or increase the coverage provided by the antenna device and/or increase the signal to interference plus noise ratio (signal to interference plus noise ratio, SINR). The first phase difference between the RF signals at the two radiating elements and potentially the amplitude difference as a further degree of freedom may also be used to improve front-to-back and cross polarization discrimination of the antenna device.

The antenna device may have a width that complies with existing regulations and may be used with existing support structures at the antenna site. This is due to the fact that two radiating elements are arranged on said common axis, e.g. stacked on top of each other.

Furthermore, the antenna device does not require a long electrical length feed network, and therefore the operating bandwidth of the antenna device is not severely limited. The first phase difference can be introduced without rotating the balun feed structure, which results in smaller size, lower cost, lower production complexity.

In general, the antenna device of the first aspect has the following advantages: a simple feeding of the two radiating elements is provided while achieving a high radiation directivity. Furthermore, the antenna device is suitable for broadband, easy to handle, and low cost.

Notably, the antenna device of the first aspect is described as a transmitting (non-receiving) device. However, the antenna device may also operate as a receiving device.

In an implementation form of the first aspect, the redirecting device is further configured to set a second phase difference between the RF signal at the first radiating element and the RF signal at the second radiating element in addition to the first phase difference set by the inverter.

The second phase difference may be used to balance a Voltage STANDING WAVE Ratio (VSWR) bandwidth and directivity of the antenna device. For example, the radiation fields of the two radiation units (i.e., the radio waves radiated by the radiation units) may be made to constructively interfere.

In an implementation form of the first aspect, the redirecting device comprises a first path for providing the RF signal to the first radiating element and a second path for providing the RF signal to the second radiating element, wherein the second phase difference is set by the first path, the first path having a different length than the second path.

This provides a simple way of achieving said second phase difference.

In an implementation form of the first aspect, the redirecting device of the feed structure comprises: balun (balun) connected to the first and second radiating elements; a feed line for feeding the RF signal to the balun, the feed line being connected to the balun at a single feed point.

With the redirecting device being single-point fed and balun implemented, the feeding of the two radiating elements can be simplified.

In an implementation form of the first aspect, the redirecting device of the feed structure comprises: balun connected to the first and second radiating elements; a feed line for feeding the RF signal to the balun, the feed line having a first feed portion and a second feed portion, the first feed portion being connected to the balun at a different feed point than the second feed portion.

This provides a different but efficient implementation of the redirecting device.

In one implementation of the first aspect, the balun includes two conductive portions separated by a gap, the gap intersecting the feed line at one or more feed points.

The feed line may thus be connected to the balun by a coupling feed.

In an implementation form of the first aspect, each feed point is arranged between the first radiating element and the second radiating element, or between a reflector of the antenna device and the two radiating elements, or from the top of the first radiating element.

In an implementation of the first aspect, the balun is connected to the feed line at one or more feed points by a coupling feed or a direct feed.

In one implementation of the first aspect, the inverter comprises a cross-jump structure designed such that a positive pole of the feed structure cross-jumps to one side of a negative pole of the feed structure and the negative pole of the feed structure cross-jumps to one side of the positive pole of the feed structure.

The feeding of the two radiating elements may be simplified with the inverter implemented with the cross-jump structure.

In an implementation form of the first aspect, the inverter is provided on either one of the first and second radiating elements or on a balun of the feed structure connected to the first and second radiating elements.

In an implementation manner of the first aspect, the antenna device further includes: a reflector disposed on the common axis and adapted to reflect the radio waves from the first and second radiating elements to a main radiating direction.

In an implementation manner of the first aspect, the first radiation unit and the second radiation unit are arranged in different planes.

In an implementation manner of the first aspect, the different planes are parallel to each other.

In an implementation manner of the first aspect, the first radiation unit and the second radiation unit are concentrically arranged on the common axis.

In an implementation form of the first aspect, the feeding structure is for feeding the RF signals to the first and second radiating elements in parallel.

In an implementation manner of the first aspect, at least one of the first radiating element and the second radiating element is a dual polarized radiating element.

That is, each radiating element may radiate with a first polarization and a second polarization.

In an implementation form of the first aspect, one of the first and second radiating elements is arranged closer to the reflector of the antenna device than the other radiating element and has a larger radiating area than the other radiating element.

Thus, shielding of the lower radiating element by the upper radiating element is reduced.

In an implementation manner of the first aspect, the antenna device further includes: and the support structure is used for bearing the first radiation unit and the second radiation unit, so that the two radiation units are arranged on the common axis.

In an implementation form of the first aspect, the feed structure is at least partially arranged on the support structure.

A second aspect of the present disclosure provides a method of operating an antenna device comprising a first radiating element and a second radiating element, the first and second radiating elements being disposed on a common axis, each radiating element for radiating radio waves in response to an RF signal fed to the respective radiating element, wherein the method comprises: feeding the RF signal to the first and second radiating elements; distributing power of the RF signal between the first radiating element and the second radiating element; a phase difference of 180 ° ± a is provided between the RF signal at the first radiating element and the RF signal at the second radiating element, wherein a is ∈0 °.

The method according to the second aspect may operate an antenna device according to any implementation of the first aspect. The method according to the second aspect achieves the same advantages as described for the antenna device according to the first aspect.

It should be noted that all devices, elements, units and methods described in the present application may be implemented in software or hardware elements or any combination thereof. All steps performed by the various entities described in the present application and functions to be performed by the various entities described are intended to mean that the respective entities are adapted to perform the respective steps and functions. Although in the following description of specific embodiments, specific functions or steps to be performed by external entities are not reflected in the description of specific detailed elements of the entity performing the specific steps or functions, it should be clear to a skilled person that these methods and functions may be implemented by corresponding software or hardware elements or any combination thereof.

Drawings

The aspects and implementations described above are explained in the following description of specific embodiments, taken in connection with the accompanying drawings, wherein:

Fig. 1 (a) shows a basic principle of an antenna device provided by an embodiment of the present disclosure, and fig. 1 (b) shows an implementation of the device.

Fig. 2 shows different implementations of the antenna device provided by the embodiments of the present disclosure, in particular, different examples of inverters.

Fig. 3 illustrates different implementations of an antenna device provided by embodiments of the present disclosure, in particular, different examples of a redirecting device.

Fig. 4 illustrates various exemplary implementations of an antenna device provided by embodiments of the present disclosure.

Fig. 5 shows a perspective view of an antenna apparatus provided by an embodiment of the present disclosure.

Fig. 6 shows a top view of an antenna device provided by an embodiment of the present disclosure.

Fig. 7 illustrates other exemplary implementations of antenna devices provided by embodiments of the present disclosure.

Fig. 8 illustrates a method provided by an embodiment of the present disclosure for operating an antenna apparatus of the present disclosure.

Detailed Description

Fig. 1 (a) shows an antenna apparatus 100 provided by an embodiment of the present disclosure. The antenna device 100 may be adapted to a base station of a mobile communication network. In particular, the antenna apparatus 100 may be adapted for a base station antenna driving system.

The antenna device 100 comprises a first radiating element 101 and a second radiating element 102, which are arranged on a common axis 103. Thus, the first radiation element 101 and the second radiation element 102 may be concentrically arranged on a common axis 103. For example, the two radiating elements 101 and 102 may be arranged on top of each other along a common axis 103. For example, as shown in fig. 1, the first radiation unit 101 may be disposed above the second radiation unit 102. The first radiating element 101 and the second radiating element 102 may be arranged in different planes or in different layers of the antenna device 100. These different planes or layers may be parallel to each other. Accordingly, the antenna device 100 may be referred to as a multi-layer antenna device.

Each of the radiating elements 101, 102 is for radiating radio waves in response to an RF signal fed to the respective radiating element 101 or 102. Each radiating element 101, 102 may be a dipole. Furthermore, each radiating element 101, 102 may be configured to radiate with a first polarization and a second polarization, wherein the two polarizations may be orthogonal. For this purpose, each radiating element 101, 102 may have two different dipole arms.

The antenna device 100 further comprises a feeding structure 104 for feeding RF signals to the first radiation unit 101 and the second radiation unit 102. For example, the feeding structure may be used to feed RF signals to the first radiating element 101 and the second radiating element 102 in parallel. The feed structure 104 may include a plurality of components. Thus, the feed structure comprises a redirecting device 104 for redirecting power between two or more branches, the redirecting device 104 being configured in the antenna device 100 for distributing the power of the RF signal between the first radiating element 101 and the second radiating element 102. The redirection device 104 may be a power splitter. The feed structure further comprises an inverter 105 for setting the quasi-inverting phase between the RF signal at the first radiating element 101 and the RF signal at the second radiating element 102 to a first phase difference. Inverter 105 may be a phase shifter. The first phase difference may be ±180°.

Fig. 1 (b) shows an antenna device 100 provided by an embodiment of the present disclosure, which is based on the embodiment of the antenna device 100 shown in fig. 1 (a). Like elements in fig. 1 (a) and 1 (b) have like reference numerals and are similarly implemented.

Accordingly, the antenna device 100 of fig. 1 (b) further comprises two radiating elements 101, 102, a redirecting device 104 and an inverter 105. In the antenna device 100 of fig. 1 (b), the redirecting device 104 is used to set a second phase difference 106 between the RF signal at the first radiating element 101 and the RF signal at the second radiating element 102 in addition to the first phase difference set by the inverter 105. To this end, for example, the redirecting device 105 may comprise a first path or first arm for providing RF signals to the first radiating element 101 and a second path or second arm for providing RF signals to the second radiating element 102. In this case, the second phase difference 106 may be provided by a first passage or first arm having a different length than the second passage or second arm.

It is noted that, considering fig. 1 (a) and 1 (b), the power of the RF signal is distributed between the first and second radiating elements 101 and 102. For example, it may be equally distributed between the two radiating elements 101, 102, but it may also be unevenly distributed between the two radiating elements 101, 102. In any case, a phase difference of 180++α may be set between the RF signal at the first radiating element 101 (e.g., having an absolute phase of Φ -180 °, where Φ is a determined phase value) and the RF signal at the second radiating element 102 (e.g., having an absolute phase of Φ+α). For the antenna device 100 of fig. 1 (a), α=0°, and for the antenna device 100 of fig. 1 (b), α >0 °.

In the overview of fig. 1 (a) and 1 (b), the basic principle of the antenna device 100 with dual-layer radiating elements 101, 102 is that the redirecting device 104 connects a first (e.g. upper) radiating element 101 and a second (e.g. lower) radiating element 102. One of the two radiating elements 101, 102 obtains a fixed phase inversion as a first phase difference (as shown in fig. 1 (a) and fig. 1 (b)). In addition, the two radiating elements 101, 102 may have a second phase difference 106 of α (as shown in fig. 1 (b)).

A fixed phase inversion (e.g., 180 ° phase shift) may be achieved by a cross-bar structure as the inverter 105. The cross-hopping structure may be designed such that the positive poles of the feeding structure cross-hop to one side of the negative poles of the feeding structure and the negative poles of the feeding structure cross-hop to one side of the positive poles of the feeding structure.

Fig. 2 shows different implementations of the antenna device 100 provided by embodiments of the present disclosure, which are based on the embodiments shown in fig. 1 (a) and fig. 1 (b). Like elements in the drawings have like reference numerals and are similarly implemented.

In particular, fig. 2 shows different examples of the inverter 105, in particular how the inverter 105 may be introduced at different positions of the feed structure (e.g. implemented as a cross-bar structure). For example, the inverter 105 may be provided on the first radiation unit 101 (see (a) of fig. 2) or may be provided on the second radiation unit 102 (see (c) of fig. 2). Or the inverter 105 may be provided on the balun 201 of the feeding structure of the antenna device 100 (see (b) of fig. 2 or (d) of fig. 2). Thus, the balun 201 may be connected to the first and second radiating elements 101, 102 and may be used to feed RF signals to the radiating elements 101, 102.

Fig. 2 also shows that the antenna device 200 may further comprise a reflector 204, which may be arranged on the common axis 103. The reflector 204 is for reflecting radio waves from the first radiation unit 101 and the second radiation unit 102, respectively, to the main radiation direction. Thus, the radiation directivity is increased. The second radiation element 102 may be arranged closer to the reflector 204 than the first radiation element 101. The second radiating element 102 may also have a larger radiating area than the first radiating element 101 to reduce shadowing.

Fig. 2 also shows that the antenna device 200 (in particular the feed structure) may comprise a feed line 202 for feeding RF signals to the balun 201. The feed line 202 may be connected to the balun 201 at one or more feed points.

The feed structure of the antenna device 200 may further comprise a support structure for carrying the first and second radiating elements 101, 102 such that the radiating elements 101, 102 are arranged on a common axis 103. The feed structure may be at least partially disposed on the support structure. For example, balun 201 may be disposed on a support structure, and/or feeder 202 may be disposed at least partially on the support structure.

Fig. 3 shows different implementations of the antenna device 100 provided by embodiments of the present disclosure, which are based on the embodiments shown in fig. 1 (a) and 1 (b) and 2. Like elements in the drawings have like reference numerals and are similarly implemented.

In particular, fig. 3 shows different examples of the redirecting device 104. For example, one possibility to implement the redirecting device 104 (e.g. as a power splitter) is to use a single-point feed and balun 201. For example, the redirecting device 104 may comprise a balun 201, and the feed 202 may be connected to the balun 201 at a single feed point 303 (see fig. 3 (a) and fig. 3 (c)). As another example, the feed line 202 may have a first feed portion and a second feed portion, wherein the first feed portion is connected to the balun 201 at a different feed point 303 than the second feed portion (see fig. 3 (b) and 3 (d)). That is, the feed line 202 may be connected to the balun 201 at two or more feed points 303.

Each feed point 303 may be disposed between the first radiating element 101 and the second radiating element 102 (see (b) of fig. 3, fig. 3 (c) and fig. 3 (d)), or may be disposed between the reflector 204 of the antenna device 100 and the two radiating elements 101, 102 (see (a) of fig. 3, fig. 3 (b) and fig. 3 (c)), or may be disposed from the top of the first radiating element 101. Depending on the setting position of the feed point 303, the second phase difference α between the two radiating elements 101, 102 may be changed and may be set accordingly by selecting the position of the feed point 303. Another possible implementation is to first implement the redirecting device 104 and then feed the two radiating elements 101, 102 through the two feed points 303.

The feeding may be achieved by coupling the feeds. For example, balun 201 may include two conductive portions separated by a gap, and the gap may intersect feed line 202 at one or more feed points 303. Or the feeding may be achieved by direct feeding (e.g., by a direct metal connection). In general, balun 201 may be connected to feed line 202 at one or more feed points 303 by a coupling feed or a direct feed.

The redirecting device 104 of the antenna device 100 may significantly simplify the feeding of the radiating elements 101, 102, may eliminate resonances for a wider bandwidth, may reduce the size and cost of the antenna device 100, and may reduce its production complexity.

Fig. 4 illustrates various exemplary implementations of the antenna device 100 provided by embodiments of the present disclosure, which are based on the embodiments shown in the preceding figures. Like elements in the drawings have like reference numerals and are similarly implemented.

Specifically, (a) of fig. 4 shows the antenna device 100, wherein the inverter 105 is implemented as a cross-jump structure on the balun 201. Fig. 4 (b) shows the antenna device 100, wherein the inverter 105 is implemented as a cross-jump structure on the first radiating element 101 (top radiating element). Fig. 4 (c) shows the antenna device 100 in which the inverter 105 is implemented as a cross-jump structure on the first radiating element 101 having a single-point direct feed structure. Fig. 4 (d) shows an antenna device 100 in which the inverter 105 is implemented as a cross-jump structure on the first radiating element 101 with a diecast balun 201. All the implementations of fig. 4 have been simulated or measured and exhibit a lower HBW and thus increased directivity compared to comparable conventional antenna devices.

Fig. 5 and 6 show a perspective view and a top view, respectively, of an antenna device 100 provided by an embodiment of the present disclosure. The antenna device 100 of fig. 5 and 6 is based on the embodiment shown in the previous figures. Like elements in the drawings have like reference numerals and are similarly implemented.

Fig. 5 shows an antenna device 100 with two radiating elements 101, 102 arranged on a common axis 103. Further, fig. 5 shows a balun 201 connected to the first and second radiating elements 101 and 101, and shows a feeder line 202 connected to the balun 201.

Fig. 5 also shows that the first radiating element 101 and the second radiating element 102 may each comprise a substrate 503 and may each comprise two dipole arms in or on the substrate 503. In particular, the first radiating element 101 may comprise a first top dipole arm 501a for a first polarization and a second top dipole arm 501b for a second polarization. The two top dipole arms 501a and 501b may be arranged orthogonally to each other. In particular, the second radiating element 102 may comprise a first bottom dipole arm 502a for a first polarization and a second bottom dipole arm 502b for a second polarization. The two bottom dipole arms 502a and 502b may be disposed orthogonal to each other.

Fig. 7 shows other exemplary implementations of the antenna device 100 provided by embodiments of the present disclosure, which are based on the embodiments shown in the previous figures. Like elements in the drawings have like reference numerals and are similarly implemented.

Specifically, fig. 7 (a) shows an antenna device 100 having a balun 201 provided on a support structure and a cross-jump structure implementing an inverter 105 on a first radiating element 101. Fig. 7 (b) shows an antenna device 100 having a feed line 201 connected to the balun 201 at one feed point 303 and a cross-jump structure implementing the inverter 105 on the balun 201 in the vicinity of the first radiating element 101.

Fig. 8 illustrates a method 800 provided by an embodiment of the present disclosure. The method 800 is applicable to operating an antenna device 100, such as the antenna device 100 shown in the previous figures. The antenna device 100 comprises a first radiating element 101 and a second radiating element 102, which are arranged on a common axis 103. Each radiating element 101, 102 is adapted to radiate radio waves in response to an RF signal fed to the respective radiating element 101, 102.

The method 800 comprises feeding (step 801) RF signals to the first radiating element 101 and the second radiating element 102. Thereby, the power of the RF signal is distributed (step 802) between the first radiating element 101 and the second radiating element 102. Furthermore, a phase difference of 180 ° ± α is thereby set (step 803) between the RF signal at the first radiation unit 101 and the RF signal at the second radiation unit 102, wherein α is ∈0 °.

The present disclosure has been described in connection with various embodiments as examples and in connection with implementations. However, other variations can be understood and effected by those skilled in the art by practicing the claimed subject matter, from a study of the drawings, the disclosure, and the independent claims. In the claims and in the description, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims (20)

1. An antenna device (100), characterized by comprising:

-a first radiating element (101) and a second radiating element (102), the first radiating element (101) and the second radiating element (102) being arranged on a common axis (103), each radiating element (101, 102) being adapted to radiate radio waves in response to a Radio Frequency (RF) signal fed to the respective radiating element (101, 102); and

-A feeding structure for feeding said RF signal to said first radiating element (101) and to said second radiating element (102);

Wherein the feed structure comprises a redirecting device (104) for redirecting power between two or more branches, the redirecting device (104) being for distributing the power of the RF signal between the first radiating element (101) and the second radiating element (102); and

Wherein the feed structure comprises an inverter (105) for setting a quasi-inverted phase between the RF signal at the first radiating element (101) and the RF signal at the second radiating element (102) to a first phase difference.

2. The antenna device (100) according to claim 1, wherein the redirecting device (104) is arranged to set a second phase difference (106) between the RF signal at the first radiating element (101) and the RF signal at the second radiating element (102) in addition to the first phase difference set by the inverter (105).

3. The antenna device (100) according to claim 2, wherein the redirecting device (104) comprises a first path for providing the RF signal to the first radiating element (101) and a second path for providing the RF signal to the second radiating element (102), wherein the second phase difference (106) is set by the first path, the first path having a different length than the second path.

4. An antenna device (100) according to any of claims 1-3, characterized in that the redirecting device (104) of the feed structure comprises:

Balun (201) connected to said first radiating element (101) and to said second radiating element (102); and

-A feed line (202) for feeding the RF signal to the balun (201), the feed line (202) being connected to the balun (201) at a single feed point (303).

5. An antenna device (100) according to any of claims 1-3, characterized in that the redirecting device (104) of the feed structure comprises:

Balun (201) connected to said first radiating element (101) and to said second radiating element (102); and

-A feed line (202) for feeding the RF signal to the balun (201), the feed line having a first feed portion and a second feed portion, the first feed portion being connected to the balun (201) at a different feed point (303) than the second feed portion.

6. The antenna device (100) according to claim 4 or 5, wherein the balun (201) comprises two conductive portions separated by a gap, the gap intersecting the feed line (202) at one or more feed points (303).

7. The antenna (100) according to any of the claims 4 to 6, characterized in that each feed point (303) is arranged between the first radiating element (101) and the second radiating element (102), or between a reflector (204) of the antenna device (100) and the two radiating elements (101, 102), or from the top of the first radiating element (101).

8. The antenna device (100) according to any of claims 4 to 7, wherein the balun (201) is connected to the feed line (202) at one or more feed points (303) by a coupling feed or a direct feed.

9. The antenna device (100) according to any one of claims 1 to 8, wherein the inverter (105) comprises a cross-jump structure designed such that a positive pole of the feed structure cross-jumps to one side of a negative pole of the feed structure and the negative pole of the feed structure cross-jumps to one side of the positive pole of the feed structure.

10. The antenna device (100) according to any of claims 1 to 9, wherein the inverter (105) is arranged on either one of the first radiating element (101) and the second radiating element (102) or on a balun (201) connected to the feed structure of the first radiating element (101) and the second radiating element (102).

11. The antenna device (100) according to any one of claims 1 to 10, further comprising: -a reflector (204), said reflector (204) being arranged on said common axis (103) and being adapted to reflect said radio waves from said first radiating element (101) and said second radiating element (102) to a main radiation direction.

12. The antenna device (100) according to any of claims 1 to 11, wherein the first radiating element (101) and the second radiating element (102) are arranged in different planes.

13. The antenna device (100) according to claim 12, wherein the different planes are parallel to each other.

14. The antenna device (100) according to any one of claims 1 to 13, wherein the first radiating element (101) and the second radiating element (102) are concentrically arranged on the common axis (103).

15. The antenna device (100) according to any one of claims 1 to 14, wherein the feeding structure is adapted to feed the RF signal to the first radiating element (101) and the second radiating element (102) in parallel.

16. The antenna device (100) according to any of claims 1 to 15, wherein at least one of the first radiating element (101) and the second radiating element (102) is a dual polarized radiating element.

17. The antenna device (100) according to any of the claims 1 to 16, characterized in that one of the first radiating element (101) and the second radiating element (102) is arranged closer to the reflector (204) of the antenna device (100) than the other radiating element (102, 101) and has a larger radiating area than the other radiating element (102, 101).

18. The antenna device (100) according to any one of claims 1 to 17, further comprising: -a support structure for carrying the first radiating element (101) and the second radiating element (102) such that both radiating elements (101, 102) are arranged on the common axis (103).

19. The antenna device (100) according to claim 18, wherein the feed structure is at least partially arranged on the support structure.

20. A method (800) of operating an antenna device (100), characterized in that the antenna device comprises a first radiating element (101) and a second radiating element (102), the first radiating element (101) and the second radiating element (102) being arranged on a common axis (103), each radiating element (101, 102) being adapted to radiate radio waves in response to a Radio Frequency (RF) signal fed to the respective radiating element (101, 102), wherein the method (800) comprises:

-feeding (801) the RF signal to the first radiating element (101) and the second radiating element (102);

-dividing the power of the RF signal between the first radiating element (101) and the second radiating element (102); and

A phase difference of 180 DEG + -alpha is set between the RF signal at the first radiating element (101) and the RF signal at the second radiating element (102), wherein alpha is equal to or greater than 0 deg.