Antenna, mobile communication base station and user device

Abstract

An antenna (14) has a first array of first dual polarized radiators (16) arranged in at least two columns, and at least one beam widening element (28). The beam widening element (28) comprises a conductive structure (30) being resonant in at least a portion of the first frequency band, wherein, with respect to a transversal direction (T) of the antenna (14), the beam widening element (28) is located outside the columns of the first radiators (16). A separation distance (s) between the beam widening element (28) and the closest one of the first radiators (16) is between 1 / 2 to 3 / 2 of a wavelength of an average frequency of the first frequency band. Further, a mobile communication base station (10) and a user device (12) are provided.

Description

[0001] Antenna, mobile communication base station and user device

[0002] Technical Field

[0003] The invention relates to an antenna, a mobile communication base station and a user device.

[0004] Background

[0005] In dual- or multi-band antennas, several types of radiators are used for radiating electromagnetic radiation in different frequency bands. Due to size restrictions, the radiator heads of the radiators for different frequency bands may overlap and thus affect the beam characteristics of one another.

[0006] For example, low-band radiators affect the beam characteristics of low mid-band or mid-band radiators that are partially located below the low-band radiators.

[0007] Solutions for influencing the beam characteristics, like the Half Power Beam Width (HPBW), are known for example from EP 3 868 250 A1 , US 2023 / 0178888 A1 and WO 2011 / 028616 A2.

[0008] For example, the Half Power Beam Width (HPBW) (also called 3 dB Beam Width) is affected and shows variations over common frequency bands, e.g. the lower mid-band between 1 .4 GHz and 2.69 GHz.

[0009] Thus, there is a need to provide an antenna having a more constant Half Power Beam Width at low costs.

[0010] Summary

[0011] For this purpose, an antenna, in particular for a mobile communication base station, is provided. The antenna comprises a first array of first dual polarized radiators designed for a first frequency band, and at least one beam widening element. The first radiators of the first array are arranged in at least two columns extending in a longitudinal direction of the antenna. The beam widening element comprises a conductive structure being resonant in at least a portion of the first frequency band. With respect to a transversal direction of the antenna, the beam widening element is located on a side of an outer one of the columns of the first radiators facing away from the other columns of first radiators, and a separation distance between the beam widening element and the closest one of the first radiators is between 1 / 2 to 3 / 2 of a wavelength of an average frequency of the first frequency band.

[0012] By providing a beam widening element having a structure resonant at least in parts of the first frequency band, and spaced apart from the first radiators by the separation distance, a very reliable and stable Half Power Beam Width (HPBW) across the first frequency band is achieved. At the same time, the at least one beam widening element may be simple and thus cost efficient.

[0013] The separation distance is, for example, defined by the distance between the center of the closest first radiator and the center of the beam widening element, in particular in the plane spanned by the longitudinal and transversal direction.

[0014] In an embodiment, the separation distance is larger than 1 / 2 of the wavelength of an average frequency of the first frequency band.

[0015] The conductive structure is, for example, made of aluminum.

[0016] The first radiators optionally overlap with second radiators, in particular their radiator heads overlap when seen in a top view. Optionally, the first radiators overlap with a coupling structure when seen in a top view.

[0017] In an embodiment, the antenna comprises a plurality of beam widening elements, wherein for each of the beam widening elements the separation distance between the respective beam widening element and the one of the first radiators, which is the closest to the respective beam widening element, is between 1 / 2 to 3 / 2 of a wavelength of an average frequency of the first frequency band, in particular wherein the plurality of beam widening elements form one or more arrays, further improving the HPBW.

[0018] For example, for each of the first radiators of the outer one of the columns a beam widening element is provided, or one less beam widening element is provided than first radiators are present in the associated outer one of the columns.

[0019] The conductive structure is, for example, resonant in at least 50% of the range of the first frequency band. In an embodiment, the separation distance is between 1 / 2 to 3 / 2 of the wavelength of the average frequency of the first frequency band, in particular the separation distance is 5 / 8 of the wavelength of the average frequency of the first frequency band, further improving the stability of the HPBW across the first frequency band.

[0020] For example, for a first frequency band ranging from 1.4 GHz to 2.69 GHz, the separation distance is between 60 mm to 110 mm, in particular between 70 mm to 100 mm.

[0021] In an embodiment, the conductive structure of the at least one beam widening element has an extension in a first direction and / or in a second direction between 1 / 4 to 1 / 2 of the wavelength of the average frequency of the first frequency band, in particular the extension in the first direction and / or in the second direction is -^= (i.e. 1 / (2- / 2)) of the wavelength of the average frequency of the first frequency band, 2' 2 leading to further improved results.

[0022] In an aspect, the extension of the conductive structure in the first direction differs from the extension of the conductive structure in the second direction, improving the squint of the antenna.

[0023] Alternatively or in addition, the antenna comprises a first polarization direction and a second polarization direction, which correspond to the polarization directions of the first dual polarized radiators, wherein the first direction corresponds to the first polarization direction and the second direction corresponds to the second polarization direction, leading to a high coupling and improved effect of the at least one beam widening element.

[0024] In particular, the first direction and second direction span the same plane as the longitudinal direction and the transversal direction.

[0025] For example, the first direction is the longitudinal direction or extends at an angle of 45° with respect to the longitudinal direction and / or the second direction is the transversal direction or extends at an angle of 45° with respect to the transversal direction.

[0026] The extension of the conductive structure in the longitudinal direction may be the same as or different from the extension in the transversal direction.

[0027] For further simplifying assembly, the at least one beam widening element may be located exclusively transversally sideways of the closest one of the first radiators.

[0028] For example, the beam widening element is arranged without offset in the longitudinal direction with respect to the closest one of the first radiators. In an aspect, the antenna comprises a ground plane, in particular a common reflector that is grounded or capacitively coupled to ground, the conductive structure of the at least one beam widening element is electrically insulated from the ground plane, in particular the conductive structure is ungrounded. This way, the effect of the beam widening element is improved further.

[0029] The common reflector may be the reflector for the first radiators as well as for the second radiators.

[0030] In an embodiment, the height of the conductive structure of the at least one beam widening element above the ground plane and / or the reflector is between 1 / 8 to 3 / 4 of the wavelength of the average frequency of the first frequency band, in particular the height is 1 / 4 of the wavelength of the average frequency of the first frequency band. Having the conductive structure at this distance from the ground plane and / or reflector further improves the stability of the HPBW.

[0031] In particular, the height is the distance between the ground plane or reflector and the conductive structure.

[0032] For example, for a first frequency band ranging from 1.4 GHz to 2.69 GHz, the height is between 20 mm to 28 mm, in particular about 24 mm.

[0033] For simplifying the antenna, the antenna may comprise a non-conductive support, in particular fixating the conductive structure to the reflector.

[0034] For example, the support is a plastic part holding the conductive structure and / or the support is a printed circuit board with applied metallizations as the conductive structure.

[0035] In an aspect, the conductive structure of the at least one beam widening element lies in a single plane, wherein the plane extends in the longitudinal direction and in the transversal direction, the plane is parallel to the ground plane, and / or the plane includes a radiator head of the first radiators, further improving the coupling to the first radiators.

[0036] For example, the radiator heads of the first radiators may also extend in this plane.

[0037] The conductive structure of the at least one beam widening element is cross shaped, oval or circular, showing a further improved effect on the HPBW.

[0038] In an embodiment, the conductive structure of the at least one beam widening element comprises two elongated portions, in particular rectangular portions, crossing one another, in particular at an angle of 90°. The elongated portions reliably couple to the first radiators, leading to a further stabilizing effect on the HPBW. In an aspect, the elongated portions have a length between 1 / 4 to 1 / 2 of the wavelength of the average frequency of the first frequency band, in particular the length of the wavelength of the average frequency of the first frequency band; and / or the elongated portions have a width between 0 to 15 / 100 of the wavelength of the average frequency of the first frequency band, in particular the width is 4 / 100 of the wavelength of the average frequency of the first frequency band, leading to further improved results.

[0039] The elongated portions may have same or different length and / or the elongated portions may have the same or different width, which improves the squint of the antenna to boresight or the radiation direction.

[0040] For example, for a first frequency band ranging from 1 .4 GHz to 2.69 GHz, the length is between 35 mm to 50 mm, in particular larger or equal to 40 mm and smaller or equal to 45 mm.

[0041] In order to improve the coupling to the first radiators, the elongated portions may extend at an angle of 45° with respect to the longitudinal direction and the transversal direction, and / or the first radiators have a first polarization direction and a second polarization direction, wherein the one of the elongated portions may extend parallel to the first polarization direction and the other of the elongated portions may extend parallel to the second polarization direction.

[0042] The first and second polarization direction of the first radiators may correspond to the first and second direction of the conductive structure of the at least one beam widening element.

[0043] In case of horizontal / vertical polarization of the first radiators, the first and second polarization direction as well as the first and second direction coincide with the longitudinal or transversal direction, respectively.

[0044] In an embodiment, the antenna comprises a plurality of second dual polarized radiators designed for a second frequency band, in particular forming a second array, wherein one or more of the first radiators overlap with one or more of the second radiators when seen in a top view. This way, a dual-band antenna is provided.

[0045] In order to provide a multi-band antenna, the antenna may comprise at least one further array of further dual polarized radiators designed for a frequency band different from the first frequency band, in particular wherein the further radiators are arranged between the second radiators and the reflector.

[0046] For above mentioned purpose a mobile communication base station is further provided. The base station has at least one antenna as described above. Further, for above mentioned purpose, a user device for mobile communication is provided. The user device has at least one antenna as described above.

[0047] The features and advantages described with respect to the antenna also apply to the base station and / or the user device and vice versa.

[0048] Brief Description of the Drawings

[0049] Further features and advantages will be apparent from the following description as well as the accompanying drawings, to which reference is made. In the drawings:

[0050] Figure 1 shows a mobile communication base station according to an embodiment of the invention with an antenna according to an embodiment of the invention, and a user device according to an embodiment of the invention with an antenna according to an embodiment of the invention,

[0051] Figure 2 shows a simplified top view of the antenna of the mobile communication base station of Figure 1 ,

[0052] Figure 3 shows an enlarged perspective view of a portion of the antenna of Figure 2,

[0053] Figure 4 shows the conductive structure of one beam widening element of the antenna of

[0054] Figure 2,

[0055] Figure 5 shows a schematic cross sectional view of the antenna of Figure 2,

[0056] Figure 6 shows diagram of the Half Power Beam Width (HPBW) over frequency of an antenna according to the prior art and two antennas according to the invention,

[0057] Figures 7, 8, 9 show schematic top views of the conductive structure of beam widening elements of an antenna according to a second, third and fourth embodiment of the invention, respectively, and

[0058] Figures 10, 11 show diagrams of the Squint and the HPBW, respectively, over frequency of two embodiments of an antenna according to the invention.

[0059] Detailed Description

[0060] Figure 1 shows an embodiment of a mobile communication base station 10 and an embodiment of a user device 12.

[0061] The mobile communication base station 10 has a plurality of antennas 14 for providing speech and data connections to user devices. Mobile communication base stations 10 are also referred to as mobile communication cell sites. The mobile communication base station 10 may be an access network node of a radio access network of a telecommunication network, or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points.

[0062] Moreover, as will be appreciated by those of skilled in the art, an access a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof.

[0063] For example, in some embodiments, the mobile communication base station 10 is an Open-RAN (ORAN) network node. An ORAN network node is a node in the telecommunication network that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network, including one or more network nodes and / or core network nodes.

[0064] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (0- DU), and an open central unit (O-CU).

[0065] The antenna 14 of the mobile communication base station 10 is a dual- or multiband antenna to provide speech and data connections in various frequency bands.

[0066] The user device 12 has an antenna 14 and may be a mobile phone, a laptop computer, a customer premises equipment (CPE) or the like. The antenna 14 of the user device 12 is also a dual- or multiband antenna allowing a speech and / or data connection to the mobile communication base station 10 and / or to a communication satellite.

[0067] Figure 2 shows exemplarily an antenna 14 of the mobile communication base station 10 in a simplified top view, and Figure 3 shows a portion of the antenna 14 in an enlarged perspective view.

[0068] Even though the antenna 14 of the mobile communication base station 10 is discussed in the following, the same applies for the antenna 14 of the user device 12.

[0069] The antenna 14 has a plurality of first dual polarized electromagnetic radiators 16, a plurality of second dual polarized electromagnetic radiators 18, and a common reflector 22. Further, the antenna 14 may also have a plurality of third dual polarized electromagnetic radiators (not shown for simplification) or more than three kinds of radiators. The terms "first", "second" and "third" are used within this disclosure only for differentiation purposes and do not imply any order or quality of the items.

[0070] The first radiators 16 and the second radiators 18 each have a radiator head 24 and a support 26. The radiator head 24 is mounted to the reflector 22 by means of the support 26. The same holds true for the third dual polarized electromagnetic radiators.

[0071] The radiator heads 24 of the first radiators 16 are closer to the reflector 22 than the radiator heads 24 of the second radiators 18. For example, the third dual polarized radiators' radiator heads are closer to the reflector 22 than the radiator heads 24 of the first radiators 16.

[0072] The first radiators 16 form a first array designed for a first frequency band. Thus, the first radiators 16 are designed to transmit and receive electromagnetic waves in the first frequency band. For example, the first frequency band lies above 1 GHz, e.g. ranging from 1 .4 GHz to 2.69 GHz.

[0073] Likewise, the second radiators 18 form a second array for a second frequency band. Thus, the second radiators 18 are designed to transmit and receive electromagnetic waves in a second frequency band.

[0074] Similarly, the third radiators form a third array for a third frequency band, and so forth.

[0075] The second frequency band lies below the first frequency band, in particular fully, i.e. not overlapping with the first frequency band.

[0076] For example, the second frequency band lies below 1 .0 GHz, in particular the second band lies between 600 MHz and 960 MHz.

[0077] The third frequency band lies above the first frequency band, in particular fully, i.e. not overlapping with the first frequency band, e.g. between 3.4 GHz and 3.8 GHz.

[0078] The first radiators 16 and the second radiators 18 are interleaved with one another. As can be seen in Figure 2, the radiator heads 24 of the first and second radiators 16, 18 overlap with one another with respect to an orthogonal projection onto the common reflector 22, i.e. in a top view.

[0079] The first radiators 16 and the second radiators 18 are arranged in columns. In the shown example, the antenna 14 comprises two columns of first radiators 16 having ten first radiators 16 each, and two columns of second radiators 18 having five second radiators 18 each.

[0080] It is also conceivable that more than two columns of first radiators 16 and / or second radiators 18 are present, for example 4, 6 or 8 columns. Further, the third radiators and further radiators may also be interleaved with the first radiators 16 and the second radiators 18.

[0081] The columns extend in a direction of the antenna 14 referred to as the longitudinal direction L of the antenna 14 within this disclosure.

[0082] The transversal direction T of the antenna 14 is regarded as the direction perpendicular to the longitudinal direction L, wherein the reflector 22 extends in a plane spanned by the longitudinal direction L and the transversal direction T.

[0083] Further, the antenna 14 has a radiation direction R being perpendicular to the longitudinal direction L and the transversal direction T. The radiation direction R is, for example, perpendicular to the reflector 22.

[0084] Directional terms like "up", "down", "above", "vertical", etc. are to be understood with respect to the radiation direction R of the radiator (also referred to as "vertical").

[0085] The reflector 22 is located below the first radiators 16 and the second radiators 18. The reflector 22 is in particular of metal, or a metallized carrier, for example a metallized PCB. It is also conceivable, that the reflector 22 comprises a Frequency Selective Surface (FSS) or a metamaterial.

[0086] The reflector 22 is grounded or capacitive coupled to ground and thus provides a ground plane.

[0087] Further, the antenna 14 comprises multiple beam widening elements 28.

[0088] The antenna 14 further comprises a first polarization direction P1 and a second polarization direction P2 which correspond to the polarization directions of the first and second dual polarized radiators 16, 18.

[0089] In the shown embodiment, the polarization of the first and second radiators 16, 18 is ±45° so that the first polarization direction P1 and the second polarization direction P2 are arranged at an angle of +45° and -45°, respectively, with respect to the longitudinal direction L.

[0090] The beam widening elements 28 comprise a conductive structure 30 and a non-conductive support 32.

[0091] Figure 4 shows an enlarged view of the conductive structure 30 of the beam widening elements 28 of Figure 3, and Figure 5 shows a cross sectional view of the antenna 14, also showing the non-conductive support 32 of the beam widening elements 28.

[0092] In general, the conductive structure 30 is designed such that it is resonant at least in a portion of the first frequency band. In the example of the first embodiment, the conductive structure 30 comprises two elongated portions 34, which may be rectangular.

[0093] The elongated portions 34 cross each other, in particular at their center, at an angle of 90°. The elongated portions are electrically, in particular galvanically connected to one another.

[0094] The conductive structure 30 is thus cross shaped.

[0095] In the first embodiment, both elongated portions 34 have the same length I and the same width w.

[0096] The length I of the elongated portions 34 may be between 1 / 4 to 1 / 2 of a wavelength of an average frequency of the first frequency band. In particular, the length I is -^= of the wavelength of the average 2-y2 frequency of the first frequency band.

[0097] The width w of the elongated portions 34 may be between 0 and 15 / 100 of the wavelength of the average frequency of the first frequency band, in particular the width w of the elongated portions 34 is 4 / 100 of the wavelength of the average frequency of the first frequency band.

[0098] For example, in the first embodiment, the length I may be between 35 mm to 50 mm, in particular larger or equal to 40 mm and smaller or equal than 45 mm.

[0099] The conductive structure 30 may be made of aluminum and the support 32 may be a plastic part. It also conceivable, that the support 32 is a printed circuit board and the conductive structure 30 is applied to one or more of the surfaces of the printed circuit board as a metallization.

[0100] The elongated portions 34 extend in a first direction D1 of the beam widening element 28 and in a second direction perpendicular to the first direction D1 of the beam widening element, respectively.

[0101] Thus, the extension e of the beam widening element 28 in its first direction and in its second direction corresponds to the length I of the elongated portions 34.

[0102] Due to the alignment of the elongated portions 34 in an angle of 45° with respect to the longitudinal direction L and the transversal direction T, the extension of the conductive structure 30 and with that of the beam widening element 28 in the longitudinal direction L and / or the transversal direction T is smaller than the length I of the elongated portions 34.

[0103] The first direction D1 of the beam widening element 28 corresponds to the first polarization direction P1 of the first radiators 16, and the second direction D2 of the beam widening element 28 corresponds to the second polarization direction P2 of the first radiators 16, or vice versa. In other words, the elongated portions 34 extend in one of the polarization directions P1 , P2 of the first radiators 16 each.

[0104] As a consequence, the elongated portions 34 also extend at an angle of 45° with respect to the longitudinal direction L and the transversal direction T.

[0105] The elongated portions 34 are arranged in a single plane, the plane being parallel to the plane spanned by the longitudinal direction L and the transversal direction T.

[0106] Thus, the conductive structure 30 of the beam widening element 28 is parallel to the radiator heads 24 and / or the reflector 22, as can be seen in Figure 5.

[0107] The conductive structure 30 is electrically insulated from the ground plane, e.g. the reflector 22, for example by means of the non-conductive support 32.

[0108] The height h of the conductive structure 30 above the ground plane, e.g. the reflector 22, is between 1 / 8 to 3 / 4 of the wavelength of the average frequency of the first frequency band. For example, the height h is 1 / 4 of the wavelength of the average frequency of the first frequency band.

[0109] For example, in the first embodiment, the height h is between 20 mm to 28 mm, in particular about 24 mm.

[0110] Further, as can be seen in Figure 5, the height h of the conductive structure 30 may be the same height with which the radiator heads 24 of the first radiators 16 are mounted above the reflector 22. In other words, it is conceivable that the conductive structure 30 of the beam widening element 28 is in the same plane as the radiator heads 24 of the first radiators 16.

[0111] The arrangement and number of beam widening elements 28 in the longitudinal direction L and the transversal direction T is best seen in Figure 2.

[0112] In the embodiment shown in Figure 2, the array of first radiators 16 consists of two columns. In this case, each of the columns is regarded as an outer column with respect to the transversal direction T. In case of more than two columns, the outer columns, i.e. the outer one of the columns of the first radiators 16 are the outer most columns with respect to the transversal direction T.

[0113] In the shown embodiment, for each one of the first radiators 16 of the outer columns, a beam widening element 28 as described above is provided.

[0114] The beam widening elements 28 are located outside of the first array of first radiators 16, i.e. outside of the columns in the transversal direction T. The beam widening elements 28 are located on the side of an outer column being the side facing away from the other columns of the first area of first radiators 16.

[0115] For example, in Figure 2, for the left hand outer column, the beam widening element 28 is arranged to the left of the column, whereas for the right hand outer column, the beam widening elements 28 are arranged to the right of the respective column.

[0116] For each of the beam widening elements 28 there exists a first radiator 16 which is closest to this particular beam widening element 28.

[0117] With respect to this respective closest first radiator 16, the beam widening elements 28 are arranged at a separation distance s.

[0118] The separation distance s is the distance between the center of the beam widening element 28 to the center of the respective closest first radiator 16. The center is in particular the geometric center of the radiator head 24 of the first radiator 16 or the geometric center of the conductive structure 30 of the beam widening element 28 in the plane spanned by the longitudinal direction L and the transversal direction T, respectively.

[0119] The separation distance s extends thus in the plane spanned by the longitudinal direction L and the transversal direction T.

[0120] The separation distance s is between 1 / 2 to 3 / 2, in particular between 4 / 8 to 6 / 8 of the wavelength of the average frequency of the first frequency band. For example, the separation distance s is 5 / 8 of the wavelength of the average frequency of the first frequency band. In the example of the first embodiment, the separation distance is thus between 60 mm to 110 mm, in particular between 70 mm to 100 mm.

[0121] With respect to the longitudinal direction L, in the first embodiment, the beam widening elements 28 are located exclusively transversally sideways of the respective closest one of the first radiators 16, i.e. the beam widening elements 28 in the respective first radiator 16 lie on the same line in the transversal direction T. No offset in the longitudinal direction L between the beam widening element 28 and the respective first radiator 16 is present.

[0122] For example, the beam widening elements 28 are located in locations or close to locations in the grid formed by the first radiators 16 in the columns of first radiators 16.

[0123] It is also conceivable, that there are not as many beam widening elements 28 as first radiators 16 in the outer columns, but for N first radiators 16 in an outer column there are N-1 beam widening elements 28 provided that are associated with the respective outer column. Fewer beam widening elements 28 per column (e.g. N=N-2, N-3, ...) are also conceivable.

[0124] During use of the antenna 14, the first radiators 16 emit electromagnetic radiation in the first frequency band. This electromagnetic radiation induces currents in the conductive structure 30 of the beam widening elements 28 and the conductive structures 30 are in resonance with the first radiators 16. Thus, the beam widening elements 28 also emit, to a lesser degree, electromagnetic radiation in the first frequency band which leads to a widening of the Half Power Beam Width (HPBW) of the antenna 14 in the first frequency band.

[0125] This effect can be seen in Figure 6 showing the Half Power Beam Width over the frequency of the first frequency band for three different antennas. The solid line shows an antenna 14 without beam widening elements 28, the dashed line shows the HPBW for an antenna 14 according to the first embodiment with a length I of the elongated portions 34 of 40 mm and the dotted line shows the HPBW for an antenna 14 according to the first embodiment having a length I of the elongated portions 34 of 45 mm.

[0126] The resonance of the beam widening elements 28 are closer such that they lie in portions of the first frequency band where the HPBW would be small, e.g. between 2.55 GHz and 2.65 GHz in the example of Figure 6.

[0127] As can be seen, the beam widening elements 28 lead to an increase of the Half Power Beam Width and thus a widening of the beam, in particular at very high frequencies, so that the HPBW is more constant across the first frequency band.

[0128] Thus, an antenna with a more constant HPBW at low costs is provided.

[0129] It is also conceivable, that the beam widening elements 28 are not the same throughout the antenna 14 but that beam widening elements 28 with different conductive structures 30 and thus different resonance frequencies are used to improve the performance across the first frequency band.

[0130] Figures 7, 8 and 9 show further embodiments of an antenna 14 according to the invention which substantially corresponds to the first embodiment. Thus, in the following, only the differences are discussed and the same and functionally the same components are labeled with the same reference signs.

[0131] Figures 7, 8 and 9 show top views of the conductive structures 30 of the beam widening elements 28 according to a second, third and fourth embodiment. In the second embodiment shown in Figure 7, the conductive structure 30 comprises also two elongated portions 34 arranged in a cross. However, the lengths 11 , 12 and optionally also the widths w1 , w2 of the elongated portions 34 differ from one another. One of the elongated portions may be smaller and thinner than the other one. The center of the conductive structure may be regarded as the point in which the two elongated portions 34 cross.

[0132] This arrangement leads to an improvement of the squint behavior, as the elongated portions resonate at different frequencies.

[0133] The improvement can be seen in Figures 10 and 11 showing the Squint and HPBW, respectively, for crossed elongated portions 34 with the same lengths 11 , 12 (solid lines) and with different lengths 11 , 12 (dashed lines). As seen in Figure 10, the squint defined in degrees (the direction of maximum power level) is getting better to boresight or in radiation direction R, if a mix of different lengths 11 , 12 are used. Also, as seen in Figure 10, the HPBW defined in degrees is getting more stable with different lengths 11 , I2 of the elongated portions 34.

[0134] The conductive structures 30 of the third and fourth embodiments of Figures 8 and 9, respectively, are not crossed elongated portions.

[0135] The conductive structures 30 are closed rings, in case of Figure 8 an oval ring and in case of Figure 9 a circular ring.

[0136] In particular, in the fourth embodiment in case of the circular conductive structure 30, the extension e of the conductive structures 30 in the longitudinal direction L and in the transversal direction T is the same as in the first and second direction D1 , D2. The extension e may be 1 / 4 to 1 / 2 of the wavelength of the average frequency of the first frequency band, in particular -^=. In other words, the first direction D1

[0137] 2' 2 and the second direction D2 extend in the longitudinal direction L and the transversal direction T, respectively.

Claims

Claims1. Antenna (14), in particularfor a mobile communication base station (10), comprising a first array of first dual polarized radiators (16) designed for a first frequency band, and at least one beam widening element (28), wherein the first radiators (16) of the first array are arranged in at least two columns extending in a longitudinal direction (L) of the antenna (14), wherein the beam widening element (28) comprises a conductive structure (30) being resonant in at least a portion of the first frequency band, wherein, with respect to a transversal direction (T) of the antenna (14), the beam widening element (28) is located on a side of an outer one of the columns of the first radiators (16) facing away from the other columns of first radiators (16), and wherein a separation distance (s) between the beam widening element (28) and the closest one of the first radiators (16) is between 1 / 2 to 3 / 2 of a wavelength of an average frequency of the first frequency band.

2. Antenna according to claim 1 , characterized in that the antenna (14) comprises a plurality of beam widening elements (28), wherein for each of the beam widening elements (28) the separation distance (s) between the respective beam widening element (28) and the one of the first radiators (16), which is the closest to the respective beam widening element (28), is between 1 / 2 to 3 / 2 of a wavelength of an average frequency of the first frequency band, in particular wherein the plurality of beam widening elements (28) form one or more arrays.

3. Antenna according to claim 1 or 2, characterized in that the separation distance (s) is between 1 / 2 to 3 / 2 of the wavelength of the average frequency of the first frequency band, in particular the separation distance (s) is 5 / 8 of the wavelength of the average frequency of the first frequency band.

4. Antenna according to any of the preceding claims, characterized in that the conductive structure (30) of the at least one beam widening element (28) has an extension (e) in a first direction (D1) and / or in a second direction (D2) of the beam widening element (28) between 1 / 4 to 1 / 2 of the wavelength of the average frequency of the first frequency band, in particular the extension (e) in the first direction (D1) and / or in the second direction (D2) of the wavelength of the average frequency of the firstfrequency band.

5. Antenna according to claim 4, characterized in that the extension (e1) of the conductive structure (30) in the first direction (D1) differs from the extension (e2) of the conductive structure (30) in the second direction (D1); and / orthat the antenna (14) comprises a first polarization direction (P1) and a second polarization direction (P2), which correspond to the polarization directions of the first dual polarized radiators (16), wherein the first direction (D1) corresponds to the first polarization direction (P1) and the second direction (D2) corresponds to the second polarization direction (P2).

6. Antenna according to any of the preceding claims, characterized in that the at least one beam widening element (28) is located exclusively transversally sideways of the closest one of the first radiators (16).

7. Antenna according to any of the preceding claims, characterized in that the antenna (14) comprises a ground plane, in particular a common reflector (22) that is grounded or capacitively coupled to ground, the conductive structure (30) of the at least one beam widening element (28) is electrically insulated from the ground plane, in particular the conductive structure (30) is ungrounded.

8. Antenna according to claim 7, characterized in that the height (h) of the conductive structure (30) of the at least one beam widening element (28) above the ground plane and / or the reflector (22) is between 1 / 8 to 3 / 4 of the wavelength of the average frequency of the first frequency band, in particular the height (h) is 1 / 4 of the wavelength of the average frequency of the first frequency band.

9. Antenna according to any of the preceding claims, characterized in that the antenna (14) comprises a non-conductive support (32), in particular fixating the conductive structure (30) to the reflector (22).

10. Antenna according to any of the preceding claims, characterized in that the conductive structure (30) of the at least one beam widening element (28) lies in a single plane, wherein the plane extends in the longitudinal direction (L) and in the transversal direction (T), the plane is parallel to the ground plane, and / or the plane includes a radiator head (24) of the first radiators (16).11 . Antenna according to any of the preceding claims, characterized in that the conductive structure (30) of the at least one beam widening element (28) is cross shaped, oval or circular.

12. Antenna according to any of the preceding claims, characterized in that the conductive structure (30) of the at least one beam widening element (28) comprises two elongated portions (34), in particular rectangular portions, crossing one another, in particular at an angle of 90°.

13. Antenna according to claim 12, characterized in that the elongated portions (34) have a length (I) between 1 / 4 to 1 / 2 of the wavelength of the average frequency of the first frequency band, in particular the length (I) is -^= of the wavelength of the average frequency of the first frequency band; and / orthat the elongated portions (34) have a width (w) between 0 to 15 / 100 of the wavelength of the average frequency of the first frequency band, in particular the width (w) is 4 / 100 of the wavelength of the average frequency of the first frequency band.

14. Antenna according to claim 12 or 13, characterized in that the elongated portions (34) extend at an angle of 45° with respect to the longitudinal direction (L) and the transversal direction (T), and / or that the first radiators (16) have a first polarization direction (P1) and a second polarization direction (P2), wherein one of the elongated portions (34) extends parallel to the first polarization direction (P1) and the other of the elongated portions (34) extends parallel to the second polarization direction (P2).

15. Antenna according to any of the preceding claims, characterized in that the antenna (14) comprises a plurality of second dual polarized radiators (18) designed for a second frequency band, in particular forming a second array, wherein one or more of the first radiators (16) overlap with one or more of the second radiators (18) when seen in a top view.

16. Antenna according to any of the preceding claims, characterized in that the antenna (14) comprises at least one further array of further radiators designed for a frequency band different from the first frequency band, in particular wherein the further radiators are arranged between the second radiators (18) and the reflector (22).

17. Mobile communication base station having at least one antenna (14) according to any of the claims 1 to 15.

18. User device for mobile communication having at least one antenna (14) according to any of the claims 1 to 15.

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