WO2020119883A1

WO2020119883A1 - Antenna comprising high and low band arrays

Info

Publication number: WO2020119883A1
Application number: PCT/EP2018/084211
Authority: WO
Inventors: Juan Segador Alvarez; Dingjiu DAOJIAN; Bruno BISCONTINI
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-12-10
Filing date: 2018-12-10
Publication date: 2020-06-18
Anticipated expiration: 2021-06-10

Abstract

An antenna for mobile communications comprises a plurality of Low Band (LB) radiating elements and a plurality of High Band (HB) radiating elements. The LB radiating elements may be operated as one LB array while the HB radiating elements may be operated as an even number of HB arrays. For instance, the antenna may have a 1L2H, 1L4H, 1L6H etc. configuration. The HB radiating elements are arranged in multiple parallel columns and the LB radiating elements are distributed over two or more columns from the multiple parallel columns, wherein each LB radiating element is co-located with one of the HB radiating elements. The antenna has got a good radiation performance.

Description

ANTENNA COMPRISING HIGH AND LOW BAND ARRAYS

TECHNICAL FIELD

The present invention relates to an antenna for mobile communications, particularly to a multi band antenna. The antenna comprises at least one Low Band (LB) array and a plurality of High Band (HB) arrays, specifically one LB array and an even number of HB arrays. For instance, the antenna may have a 1L2H, 1L4H, 1L6H etc. configuration (the letter“L” stands for Low Band, and the letter“H” stands for High Band). The LB radiating elements of the at least one LB array are distributed over at least two HB arrays in all embodiments of the antenna.

BACKGROUND

With the current Long-Term Evolution (LTE) advanced deployments and looking forward to 5G, in order to fully exploit the capability of the new radio standards, there is a growing demand in the market to develop antennas that have more arrays per band and support new frequency bands as well.

The new architectures should support 4x4 and 8x8 Multi-input Multi-output (MIMO) (which is necessary in higher frequency bands, but is also wished for in lower frequency bands, so as to be ready for future deployments). This means that the number of ports/antenna arrays needs to be duplicated at least in the higher frequency bands.

However, in spite of such an increased number of bands and ports per band, the limitation of having only one (or a maximum of two) antenna/s per antenna sector is still a strict requirement. It is not possible to add new“boxes” in an antenna site, because this would involve an increase of the site renting costs, and therefore operating costs for the operator (Network OPEX). For similar reasons, it is also not possible to increase the dimensions of the antenna. In order to facilitate the site acquisition and/or be able to reuse current mechanical support structures in the sites, the width and therefore the wind-load of any new antennas should further be comparable to legacy products.

Moreover, in spite of the strict limitations in the dimensions and numbers of antennas per sector, the RF performance of any new antenna should be equivalent to legacy products, in order to maintain (or even improve) the coverage area and throughput. The development of multiband antennas that can support LB plus a large number of HBs, i.e. 4 or 6 HB arrays, is being strongly demanded by the market. More specifically, in order to support 8T8R in the HB or 2 x 4T4R without duplexers, it is necessary to move from a“classical” configuration like 1 x 690-960 MHz + 2 or 3 x 1.7-2.7 GHz (1L2H or 1L3H) to more advanced architectures like 1L4H.

Due to width limitations and the“high-density” of HB radiating elements in HB arrays, a key point of design for any new antenna is in particular the shape and arrangement of LB radiating elements for forming a LB array coexisting with a large number of HB arrays.

An example arrangement of LB radiating elements is the so-called side-by-side configuration, in which the LB radiating elements are of the cross-dipole type and arranged in the center of the antenna. Such an arrangement is schematically illustrated in FIG. 14 for a 1LH4 configuration (wherein the number of LB arrays is denoted with“L” and of High Band arrays with“H”). The HB arrays are arranged on both sides of the LB array and at the sides of the antenna, respectively. For the same arrangement in a 1LH2 configuration, the two outer HB columns would be omitted. This arrangement of the LB radiating elements presents several disadvantages:

• The achievable gain in the LB array when using the cross-dipole type is lower than the gain that can be achieved with a square-dipole type (4 points feeding).

• The shape of the LB radiating elements has a strong impact on the HB performance, and it is difficult to find suitable shapes that can overcome this problem and at the same time maintain the LB performance.

• The distance between the HB arrays has to be relatively large, in order to avoid shadowing by the LB radiating elements.

Alternatively, FIG. 13 illustrates another example arrangement of LB radiating elements. All the LB radiating elements are here aligned and placed in a column that extends along the vertical antenna axis, and inserted in only one of the HB arrays. Thereby, the LB radiating elements are co-located/embedded with the HB radiating elements of that HB array. The other HB arrays are free from LB radiating elements.

This type of arrangements can only be optimal when the number of HB arrays is odd (e.g., 1L1H, 1L3H, 1L5H, etc.), but it presents several disadvantages when the number of HB arrays is even like in FIG. 13 (and e.g., for 1L2H, 1L4H, 1L6H, etc.):

• The LB array cannot be placed in the center of the antenna, i.e. the radiation patterns are not symmetric.

• The performance of the different HB arrays differs, because their environment is not the same, in general not good for MIMO performance.

Overall, a better arrangement for the LB array has thus to be found.

SUMMARY

In view of the above-mentioned challenges, embodiments of the present invention aim to provide an improved antenna. An objective is to provide an antenna with a better arrangement of LB radiating elements for forming an LB array in an antenna that includes multiple HB arrays. In particular, an arrangement of the LB radiating elements is desired, which is as transparent as possible for the HB arrays, and that can at the same time maintain the LB performance (Gain, HBW) of the legacy products (1L2H, 1L3H, etc.). This should still be achievable when increasing the number of HB arrays. The LB array should be optimized with respect to both shape and arrangement of the LB radiating elements.

The objective is achieved by embodiments of the invention as provided in the enclosed independent claims. Advantageous implementations of the embodiments of the invention are further defined in the dependent claims.

In particular, in embodiments of the invention the LB radiating elements are distributed over at least two columns of HB radiating elements. In other words, at least one LB radiating element is arranged in one of the at least two columns, while at least one other LB radiating element is arranged in the other one of the at least two columns. That means that at least two LB radiating elements are displaced relative to another in a direction transverse to the at least two columns of HB radiating elements.

A first aspect of the invention provides an antenna, comprising: a plurality of HB radiating elements configured to radiate in a first frequency band, and a plurality of LB radiating elements configured to radiate in a second frequency band which is lower than the first frequency band, wherein the HB radiating elements are arranged in multiple parallel columns and the LB radiating elements are distributed over two or more columns from the multiple parallel columns, wherein each LB radiating element is co-located with one of the HB radiating elements.

In this application, the expressions“high band” (HB) and“low band” (LB) refer to two different frequency ranges, namely a first frequency band (the high band) and a second frequency band (the low band), wherein it is understood that the HB is higher in frequency than the LB. A lower range of the HB may overlap with an upper range of the LB. The expressions HB and LB may also be used as attributes of nouns to indicate that the matter described by the respective noun is associated with a HB or with a LB, respectively. For example, a HB element is an element associated with a HB, and a LB element is an element associated with a LB.

Each column of HB radiating elements may form a separate HB array, and the plurality of LB radiating elements may form a LB array.

Two elements positioned at the same position are said to be co-located. The LB radiating elements are distributed over the two or more columns from the multiple parallel columns in the sense that each of the two or more columns comprises one or more of the LB radiating elements.

The arrangement of the LB radiating elements in the antenna of the first aspect leads to a (more) symmetric LB radiation pattern, and also to a (more) even performance of the different HB arrays or columns. Square-dipoles can be used for the LB radiating elements, thus the LB gain can be improved. Shadowing of the HB radiating elements by the LB radiating elements can further be reduced. Overall, the arrangement of the LB radiating elements is thus better than in the arrangements shown in FIG. 13 or FIG. 14. In an implementation form of the first aspect, the antenna comprises a LB feeding network connected to the plurality of LB radiating elements, for operating the plurality of LB radiating elements as a LB antenna array.

In an implementation form of the first aspect, the antenna comprises for each of the multiple columns a HB feeding network connected to the HB radiating elements of the respective column, for operating the HB radiating elements of the respective column as a HB antenna array.

That means that each HB radiating element column forms one HB array, and the LB radiating elements form one LB array. The antenna may e.g., be in a 1L2H, 1L4H or 1L6H configuration.

In an implementation form of the first aspect, the two or more columns over which the LB radiating elements are distributed each comprise the same number of LB radiating elements.

In an implementation form of the first aspect, the plurality of LB radiating elements is arranged along the columns in a zigzag pattern.

Thus, a particularly symmetric LB radiation pattern can be achieved.

In an implementation form of the first aspect, the LB radiating elements are arranged along the columns in accordance with cyclic permutations of the columns.

In one example, assuming that there are M columns (numbered 1 to M) and N LB radiating elements (numbered 1 to N), the LB radiating element number I is placed in column number J where J = I mod M and I is any integer in the range of 1 to N.

In an implementation form of the first aspect, the multiple parallel columns are adjacent to another.

In an implementation form of the first aspect, each of the LB radiating elements is located at least partly above or below the HB radiating element with which the LB radiating element is co-located. In an implementation form of the first aspect, the plurality of HB radiating elements is arranged in four parallel columns, which include two inner columns, and the plurality of LB radiating elements is arranged in the two inner columns.

In an implementation form of the first aspect, the plurality of HB radiating elements is arranged in four parallel columns, which include two outer columns, and the plurality of LB radiating elements is arranged in the two outer columns.

In an implementation form of the first aspect, the plurality of HB radiating elements is arranged in four parallel columns, which include an outer column and an inner column, and the plurality of LB radiating elements is arranged along the columns altematingly in the outer column and in the inner column.

In an implementation form of the first aspect, the HB radiating elements and/or the LB radiating elements are arranged along the columns with non-uniform spacing.

In an implementation form of the first aspect, each of the HB radiating elements and/or each of the LB radiating elements is dual-polarized.

In an implementation form of the first aspect, the antenna further comprises one or more third radiating elements configured to radiate in a frequency band which is not the first frequency band and not the second frequency band.

A second aspect of the invention provides a base station comprising an antenna according to the first aspect or any of its implementation forms, and a radio transmitter connected to the antenna.

A base station may also be referred to in the art as a network access node, a radio client device, an access client device, an access point, e.g., a Radio Base Station (RBS), which in some networks may be referred to as transmitter,“gNB”,“gNodeB”,“eNB”,“eNodeB”,“NodeB” or “B node”, depending on the technology and terminology used. The radio client devices may be of different classes such as macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. The radio client device can, for example, be a Station (STA), which is any device that contains an IEEE 802.11 -conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM). The radio client device may also be a base station corresponding to the fifth generation (5G) wireless systems.

A third aspect of the invention provides a method for producing an antenna, comprising: arranging a plurality of high band, HB, radiating elements in multiple parallel columns, wherein the plurality of HB radiating elements are configured to radiate in a first frequency band, and distributing a plurality of low band, LB, radiating elements over two or more columns from the multiple parallel columns, wherein the plurality of LB radiating elements are configured to radiate in a second frequency band which is lower than the first frequency band, wherein distributing the plurality of low band, LB, radiating elements over the two or more columns from the multiple parallel columns comprises co-locating each LB radiating element with one of the HB radiating elements.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

The above described aspects and implementation forms of the present invention will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration. FIG. 2 schematically shows an example of an antenna according to an embodiment of the invention in a 1L4H configuration.

FIG. 3 schematically shows an example of an antenna according to an embodiment of the invention in a 1L6H configuration.

FIG. 4 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration with a HB to LB ratio of 3 : 1.

FIG. 5 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration with a non-uniform HB to LB ratio.

FIG. 6 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration with an unequal number of LB radiating elements in respectively the two HB arrays.

FIG. 7 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration with a non-uniform HB to LB ratio.

FIG. 8 schematically shows an example of an antenna according to an embodiment of the invention in a 1L2H configuration with an unequal number of HB radiating elements in respectively the two HB arrays.

FIG. 9 schematically shows an example of an antenna according to an embodiment of the invention in a 1L4H configuration with a HB to LB ratio of 3 : 1.

FIG. 10 schematically shows an example of an antenna according to an embodiment of the invention in a 1L4H configuration with a non-uniform HB to LB ratio.

FIG. 11 schematically shows an example of an antenna according to an embodiment of the invention in a 1LH4 configuration with LB radiating elements arranged in the two outer HB arrays. FIG. 12 schematically shows an example of an antenna according to an embodiment of the invention in a 1L4H configuration with LB radiating elements distributed over all four HB arrays.

FIG. 13 shows an example of an antenna in 1L4H configuration.

FIG. 14 shows an example of an antenna in a 1L4H configuration.

DETAILED DESCRIPTION OF EMBODIMENTS

Illustrative embodiments of an antenna are described with reference to the figures. The details are intended to be exemplary and do not limit the scope of the present application.

FIG. 1 shows an antenna 100 according to an embodiment of the invention. The antenna 100 is a multi-band antenna, as it combines a plurality of HB radiating elements 101 and a plurality of LB radiating elements 102. In particular, the HB radiating elements 101 are configured to radiate in a first frequency band, and the plurality of LB radiating elements 102 are configured to radiate in a second frequency band. The second frequency band is thereby lower than the first frequency band.

As can be seen in FIG. 1, the HB radiating elements 101 are arranged in two parallel columns, i.e. the antenna 100 is in a 1L2H configuration. The LB radiating elements 102 are distributed over these two HB columns. Thereby, each LB radiating element 102 is co-located with one of the HB radiating elements 101.

As shown exemplarily in FIG. 1, the LB radiating elements 102 may be arranged in a zigzag configuration along the columns of the HB radiating elements 101. Thus, the LB radiating elements 102 are altematingly displaced, along the HB columns (i.e. along a vertical axis of the antenna 100), in a direction perpendicular to the columns of the HB radiating elements 101.

Typically, but not necessarily, all the LB radiating elements 102 are connected to the same LB feeding network, thus forming one LB array, whereas for the HB radiating elements 101 each column is connected to a separate HB feeding network, thus forming as many HB arrays as there are columns. Exemplarily, in the following description of the embodiments of the invention, each column of HB radiating elements 101 is referred to as a HB array, and the plurality of LB radiating elements 102 is referred to as a LB array.

With the arrangement of the LB radiating elements 102 in the antenna 100 of FIG. 1, the problems mentioned above are addressed, namely:

• The radiation pattern of the LB array is made more symmetric by distributing the LB radiating elements 102, particularly totally symmetric if the LB radiating elements 102 are altematingly placed in one column and then the other column of the two columns of HB radiating elements 101. Further, the combined radiation pattern of the LB and HB arrays is made more or even totally symmetric.

• The performance of the HB arrays (two HB arrays for the 1L2H configuration case) can be equalized. The performance at array level of the two HB arrays may be much more balanced than if all the LB radiating elements 102 were arranged in only one HB array (as e.g., shown in FIG. 13). This leads to a better MIMO performance. In addition, for antenna development and for production, there is only one type of tuning, set of parts, phase shifter cable lengths, etc.

The arrangement of the LB radiating elements 102 in the antenna 100 described with respect to FIG. 1 is particularly advantageous, when a LB array is combined with an even number of HB arrays, i.e. 1L2H (as in FIG. 1), 1L4H (e.g., FIG. 2), 1L6H (e.g., FIG. 3), which are actually also the most valuable architectures from a market perspective, since the MIMO order always duplicates, i.e. goes from 2x2 to 4x4 to 8x8 and so on. The arrangement of the LB radiating elements 102 can, however, be used also with other numbers of HB arrays. In configuration with an odd number of HB arrays, the LB radiating elements 102 may be distributed over more than two HB arrays. In configurations with more than three HB arrays, the performance of HB arrays located at the sides of the antenna 100 and of HB arrays placed in the center of the antenna 100 may be different, but still the overall performance between all the HB arrays will be more balanced than when placing all the LB radiating 101 elements aligned in one HB array.

FIG. 2 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 2 shows an antenna 100 in a 1L4H configuration, exemplarily when with LB radiating elements 102 distributed in a zigzag pattern over two of the four columns of the HB radiating elements 101.

The antenna 100 of FIG. 2 may this includes two different types of HB arrays, i.e. the two HB arrays located at the sides of the antenna 100 and the two HB arrays located in the center of the antenna 100. Notably, in the situation of the antenna shown in FIG. 13, the environment and therefore the performance of all four HB arrays is different. Thus, the antenna of FIG. 2 shows better performance.

In a practical implementation of a 1L4H antenna 100, which is based on the antenna 100 shown in FIG. 2, there may be six LB radiating elements 102 (not four as schematically illustrated in FIG. 2) placed alternatively in one of the two center columns of the HB radiating elements 101, i.e. co-located with HB radiating elements 101 from the second and third HB columns (counted from either side of the antenna). In this practical implementation, the first and fourth column, i.e. the columns located at the sides of the antenna 100, have similar performance, and also the second and third columns in the center of the antenna 100 have a similar performance. This is an advantage not only for the system performance (e.g., better MIMO performance), but also from a development and production point of view (only two different types of tuning and set of parts).

FIG. 3 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 3 shows an antenna 100 in a 1L6H configuration, exemplarily when distributing the LB radiating elements 102 in a zigzag pattern over two of the six columns of HB radiating elements 101. That is, like in the antenna 100 of FIG. 1 and FIG. 2, the plurality of LB radiating elements 102 is arranged along the columns in a zigzag pattern.

The antennas 100 shown in FIG. 1 (1L2H configuration), FIG. 2 (1L4H configuration) and FIG. 3 (1L6H configuration) have distinct advantages over the antenna types shown in FIG. 13 and 14 (exemplarily for the 1L4H configuration).

In particular, FIG. 12 depicts an example of an antenna in a 1L4H configuration not covered by the invention, in which all the LB radiating elements are arranged in one line. The disadvantages of this type of antenna have been already mentioned above and are: • The LB radiation pattern is not symmetric.

• The environment (and therefore) the performance of all 4 HB arrays is different.

FIG. 13 depicts another example of an antenna in a 1L4H configuration not covered by the invention, in which cross-dipole LB radiating elements arranged in the center of the antenna are used. In this case, the radiation pattern of the LB array is more symmetric than in the antenna of FIG. 12, but the configuration has the following disadvantages:

• The LB gain when using the cross-dipoles is typically 0.5 dB lower that when using square dipoles.

• The LB radiating elements introduce strong shadowing in the array of the HB radiating elements, which makes it difficult to control the HB radiation pattern. To overcome this problem, the distance between the two HB columns would have to be made relatively large, i.e. forcing to increase the width of the antenna and/or have non-uniform horizontal spacing between the HB columns and limiting the beamforming capabilities (due to large horizontal spacing, grating lobes appears, limiting the maximum scanning angle).

Notably, the embodiments of the invention are not limited to specific frequency bands, and therefore are not limited to any ratio of placing HB radiating elements 101 to LB radiating elements 102 along the columns (i.e. along vertical axis of the antenna 100). The HB to LB ratio is determined by the positions along the vertical axis of the antenna 100, at which LB radiating elements 102 are arranged in parallel HB arrays with aligned HB radiating element positions. For instance, if a LB radiating element 102 is placed at every second position in either one of parallel HB arrays (one free position between LB radiating elements 102), the HB to LB ratio is 2: 1. If a LB radiating element 102 is placed at every third position in either one of parallel HB arrays (two free position between LB radiating elements 102), the HB to LB ratio is 3 : 1. If a LB radiating element 102 is placed at every fourth position in either one of parallel HB arrays (three free positions between LB radiating elements 102), the HB to LB ratio is 4: 1, and so on. For the 1 L2H configuration case, the embodiment of the antenna 100 shown in FIG. 1 is optimal for a combination of frequencies of 900/2000 MHz. Therefore, the HB to LB ratio is 2: 1 along the vertical axis of the antenna 100, i.e. a LB radiating element 102 is co-located with a HB radiating element 101 at every second position along the two parallel HB radiating element columns (while at the same time being distributed over the two HB columns). However, for different frequency bands the HB to LB ratio may be different, and there may even be cases, in which the optimal HB to LB ratio is non-uniform along the vertical axis of the antenna 100, i.e. a spacing of LB radiating elements 102 along the vertical axis may be non-uniform.

Similarly for the 1L4H configuration case, the embodiment of the antenna 100 shown in FIG. 3 has LB radiating elements 102 co-located with HB radiating elements 101 in the central HB columns, i.e. the second and third column, at every second position along the vertical axis of the antenna 100. This configuration is optimal for the frequency band combination 900/2000 MHz, but may not be optimal for different frequency bands. There may be situations, in which the optimal solution is to arrange the LB radiating elements 102 co-located with the HB radiating elements 101 with a different HB to LB ratio, or in the side columns, or even alternatively co-located with HB radiating elements 101 in the side columns and central columns.

Embodiments of the inventions with different configurations of the antenna 100 are now described, especially covering the cases mentioned above.

FIG. 4 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 4 shows an antenna 100 in a 1L2H configuration. In the antenna 100 of FIG. 4, the ratio between HB radiating elements 101 to LB radiating elements 102 is 3: 1 along the vertical axis of the antenna 100, i.e. the LB radiating elements 102 are placed at every third position in either one of the two parallel HB columns. The LB radiating elements 102 are placed altematingly in one and the other column along the vertical axis of the antenna. More LB radiating elements 102 are placed in one HB column than the other.

FIG. 5 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 5 shows an antenna 100 in a 1L2H configuration. In the antenna 100 of FIG. 5, the ratio between HB radiating elements 101 to LB radiating elements 102 is non-uniform along the vertical axis of the antenna 100, i.e. the LB radiating elements 102 are placed non-regularly in positions in one of the two columns. However, at least one position along the vertical axis of the antenna 100 is free between each two adjacent LB radiating elements 102. The LB radiating elements 102 are placed altematingly in one and the other column along the vertical axis of the antenna. More LB radiating elements 102 are placed in one HB column than the other.

FIG. 6 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 6 shows an antenna 100 in a 1L2H configuration. In the antenna 100 of FIG. 6, the ratio between HB radiating elements 101 to LB radiating elements 102 is non-uniform along the vertical axis of the antenna 100. Furthermore, the LB radiating elements 102 are not equally distributed over the two parallel columns of LB radiating elements 102, i.e. there are more LB radiating elements 102 co-located with HB radiating elements 101 in one of the columns than in the other column. In comparison, in FIG. 1, 2 and 3 the two columns, over which the LB radiating elements 102 are distributed, each comprise the same number of LB radiating elements 102. The LB radiating elements 102 are not altematingly placed in one and the other column.

FIG. 7 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 7 shows an antenna 100 in a 1L2H configuration. In the antenna 100 of FIG. 7, the two columns of HB radiating elements 101 are parallel but shifted against each other along the vertical axis of the antenna 100, i.e. along the vertical axis of the antenna the HB radiating elements 101 of the two columns are not aligned (side-by-side). The LB radiating elements 102 are placed altematingly in one and the other column along the vertical axis of the antenna. The same number of LB radiating elements 102 is placed in both HB columns.

FIG. 8 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 1. In particular, FIG. 8 shows an antenna 100 in a 1L2H configuration. In the antenna 100 of FIG. 8, the ratio between HB radiating elements 101 to LB radiating elements 102 is 2: 1 along the vertical axis of the antenna 100. Furthermore, the LB radiating elements 102 are not equally distributed over the two columns of HB radiating elements 101, i.e. there are more LB radiating elements 102 co-located with HB radiating elements 101 in one of the two columns. The LB radiating elements 102 are not placed altematingly in one and the other column along the vertical axis of the antenna, but in sets of at least two placed in the same column along the vertical axis.

FIG. 9 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 2. In particular, FIG. 9 shows an antenna 100 in a 1L4H configuration. In the antenna 100 of FIG. 9, the ratio between HB radiating elements 101 to LB radiating elements 102 is 3: 1 along the vertical axis of the antenna 100, i.e. LB radiating elements 102 are placed at every third position along the vertical antenna axis. Thereby, the LB radiating elements 102 are distributed over the two central HB arrays. The LB radiating elements 102 are placed altematingly in the two central HB columns.

FIG. 10 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 2. In particular, FIG. 10 shows an antenna 100 in a 1L4H configuration. In the antenna 100 of FIG. 10, the ratio between HB radiating elements 101 to LB radiating elements 102 is non-uniform along the vertical axis of the antenna 100. The LB radiating elements 102 are further distributed over the two central HB arrays. The LB radiating elements 102 are placed altematingly in the two central HB columns.

FIG. 11 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 2. In particular, FIG. 11 shows an antenna 100 in a 1L4H configuration. In the antenna 100 of FIG. 11, the ratio between HB radiating elements 101 to LB radiating elements 102 is 2:1 along the vertical axis ofthe antenna 100, i.e. the LB radiating elements 102 are placed at every second position along the columns. The LB radiating elements 102 are thereby distributed over the two outer HB arrays, i.e. the columns of HB radiating elements 101 arranged at the sides ofthe antenna 100. The LB radiating elements 102 are placed altematingly in the two outer HB columns.

FIG. 12 shows an antenna 100 according to an embodiment of the invention, which builds on the antenna 100 shown in FIG. 2. In particular, FIG. 12 shows an antenna 100 in a 1L4H configuration. In the antenna 100 of FIG. 12, the ratio between HB radiating elements 101 to LB radiating elements 102 is 2: 1 along the vertical axis of the antenna 100. The LB radiating elements 102 are thereby distributed over all four HB arrays, i.e. all columns of HB radiating elements 101. Particularly, along the vertical axis ofthe antenna 100, the LB radiating elements 102 are arranged altematingly in a HB array arranged in the center of the antenna 100 and a HB array arranged at a side of the antenna 100. The LB radiating elements 102 are arranged along the columns in accordance with cyclic permutations of the columns.

Furthermore, a method embodiment of invention for fabricating an antenna is disclosed. The method comprises:

(1) Arranging a plurality of high band, HB, radiating elements in multiple parallel columns, wherein the plurality of HB radiating elements are configured to radiate in a first frequency band.

Just as an example, in FIG.l (the antenna is in 1L2H configuration), sixteen HB radiating elements are arranged in two parallel columns. These HB radiating elements are configured to radiate in a first frequency band.

(2) Distributing a plurality of low band, LB, radiating elements over two or more columns from the multiple parallel columns, wherein the plurality of LB radiating elements are configured to radiate in a second frequency band which is lower than the first frequency band.

By using FIG.1 as an example, four LB radiating elements are distributed over the two columns. These LB radiating elements are configured to radiate in a second frequency band. The second frequency band is lower than the first frequency band.

(3) Co-locating each LB radiating element with one of the HB radiating elements.

Also by using FIG.l as the example, each LB radiating element is co-located with one of the HB radiating element.

In the embodiments of the invention, the term“column” is used to describe the arrangement of the high band radiating element and the low band radiating element. It is known to the skilled reader that“column” may be replaced by“row” when the arrangement is described. The usage of“column” or“row” may be depended on the direction of the described arrangement.

The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as 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 the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

Claims

1. An antenna (100), comprising:

a plurality of high band, HB, radiating elements (101) configured to radiate in a first frequency band, and

a plurality of low band, LB, radiating elements (102) configured to radiate in a second frequency band which is lower than the first frequency band,

wherein the HB radiating elements (101) are arranged in multiple parallel columns and the LB radiating elements (102) are distributed over two or more columns from the multiple parallel columns, wherein each LB radiating element (102) is co-located with one of the HB radiating elements (101).

2. The antenna (100) according to claim 1, comprising a LB feeding network connected to the plurality of LB radiating elements (102), for operating the plurality of LB radiating elements (102) as a LB antenna array.

3. The antenna according to claim 1 or 2, comprising for each of the multiple columns a HB feeding network connected to the HB radiating elements (101) of the respective column, for operating the HB radiating elements (101) of the respective column as a HB antenna array.

4. The antenna according to one of the claims 1 to 3, wherein:

the two or more columns over which the LB radiating elements (102) are distributed each comprise the same number of LB radiating elements (102).

5. The antenna according to any one of the claims 1 to 4, wherein

the plurality of LB radiating elements (102) is arranged along the columns in a zigzag pattern.

6. The antenna according to any one of the claims 1 to 5 wherein

the LB radiating elements (102) are arranged along the columns in accordance with cyclic permutations of the columns.

7. The antenna according to any one of the claims 1 to 6, wherein

the multiple parallel columns are adjacent to another.

8. The antenna according to any one of the claims 1 to 7 wherein:

each of the LB radiating elements (102) is located at least partly above or below the HB radiating element (101) with which the LB radiating element (102) is co-located.

9. The antenna according to any one of the claims 1 to 8, wherein:

the plurality of HB radiating elements (101) is arranged in four parallel columns, which include two inner columns, and

the plurality of LB radiating elements (102) is arranged in the two inner columns.

10. The antenna according to any one of the claims 1 to 8, wherein:

the plurality of HB radiating elements (101) is arranged in four parallel columns, which include two outer columns, and

the plurality of LB radiating elements (102) is arranged in the two outer columns.

11. The antenna according to any one of the claims 1 to 8, wherein:

the plurality of HB radiating elements (101) is arranged in four parallel columns, which include an outer column and an inner column, and

the plurality of LB radiating elements (102) is arranged along the columns altematingly in the outer column and in the inner column.

12. The antenna according to any one of the claims 1 to 11, wherein

the HB radiating elements (101) and/or the LB radiating elements (102) are arranged along the columns with non-uniform spacing.

13. The antenna according to any one of the claims 1 to 12, wherein

each of the HB radiating elements (101) and/or each of the LB radiating elements (102) is dual-polarized.

14. A base station comprising an antenna (100) according to any one of the claims 1 to 13 and a radio transmitter connected to the antenna (100).

15. A method for producing an antenna (100), comprising: arranging a plurality of high band, HB, radiating elements in multiple parallel columns, wherein the plurality of HB radiating elements (101) are configured to radiate in a first frequency band; and

distributing a plurality of low band, LB, radiating elements (102) over two or more columns from the multiple parallel columns, wherein the plurality of LB radiating elements (102) are configured to radiate in a second frequency band which is lower than the first frequency band, and wherein distributing the plurality of LB radiating elements (102) over the two or more columns comprises co-locating each LB radiating element (102) with one of the HB radiating elements (101).