Multi-panel antenna unit, and antenna system

Abstract

The present disclosure provides a multi-panel antenna unit configured to be side-mounted to a mounting structure, the multi-panel antenna comprising: a housing; a plurality of first antenna elements associated with a first panel and forming a first antenna array arranged within the housing, the first antenna array having a first main radiation direction; and a plurality of second antenna elements associated with a second panel and forming a second antenna array arranged within the housing, the second antenna array having a second main radiation direction, wherein the first panel and the second panel are arranged in parallel, and wherein the first main radiation direction is opposite to the second main radiation direction. An antenna system is also disclosed.

Description

[0001] Multi-panel antenna unit, and antenna system

[0002] TECHNICAL FIELD

[0003] The present disclosure provides a multi-panel antenna unit configured to be side- mounted to a mounting structure, and an antenna system comprising at least one such multi-panel antenna unit.

[0004] BACKGROUND

[0005] Due to the rising demand for mobile network communications, network providers are tasked with providing more and more antenna systems to provide large spatial coverage for wireless communications over various frequencies.

[0006] Traditionally, a plurality of communication antennas was mounted to an antenna mast, each covering a different spatial area or operating at a different frequency.

[0007] In recent years, antenna arrays formed by multiple antenna elements have taken over as preferred implementation, yielding high directivity, enabling beamforming and supporting various advanced communication techniques complying with modern communication standards such as 4G, also known as Long Term Evolution (LTE), or 5G, also known as new Radio (NR). On the downside, such antenna arrays typically require more space than single communication antennas or antenna elements, and tend to heat up during use.

[0008] It is known to arrange antenna arrays, differing in their operating frequencies, next to one another over a common reflector within a same housing to save space. Such solutions are restricted to a common radiation direction of the antenna arrays associated with one and the same spatial sector, which means that multiple such units need to be provided in order to cover additional spatial sectors.

[0009] SUMMARY

[0010] There is a need for a technique that solves one or more of the above or other problems. According to a first aspect, a multi-panel antenna unit (MPAU) is provided. The MPAU is configured to be side-mounted to a mounting structure, and comprises a housing. The MPAU further comprises a plurality of first antenna elements associated with a first panel and forming a first antenna array arranged within the housing, the first antenna array having a first main radiation direction. The MPAU further comprises a plurality of second antenna elements associated with a second panel and forming a second antenna array arranged within the housing, the second antenna array having a second main radiation direction. The first panel and the second panel are arranged in parallel and the first main radiation direction is opposite to the second main radiation direction.

[0011] The MPAU may be configured to form (e.g., at least a part of) a base station (BS). The antenna arrays of the MPAU may be configured to enable wireless communication with one or more (e.g., mobile) communication units such as at least one wireless network node and / or at least one user equipment (UE).

[0012] The mounting structure may comprise or be an antenna mast. The mounting structure may comprise or be a building. The MPAU may be configured to be mounted laterally to the mounting structure. The MPAU may be configured to be mounted such that the housing is offset from a longitudinal axis of the mounting structure. The MPAU may be configured to be mounted to the mounting structure such that the first panel and the second panel extend laterally away from the mounting structure. The MPAU may be configured to be mounted to the mounting structure such that the mounting structure extends along (e.g., parallel to) the first and / or the second panel. The MPAU may be configured to be mounted to the mounting structure such that the mounting structure extends along (e.g., parallel to) at least a part of a length of first and / or the second panel.

[0013] An antenna element according to the present disclosure may be a radiator configured to emit electromagnetic radiation. Such antenna element may be configured to emit electromagnetic radiation having a predefined polarization. For example, such (e.g., dual-polarization) antenna element comprises two dipoles, each associated with a dipole-specific polarization direction. Such antenna element may be configured to operate at a predefined operating frequency lying within a predefined frequency band. An antenna array according to the present disclosure may be configured as an active antenna array (e.g., a phase-controlled antenna array) and may enable beamforming and beamsteering. In accordance with the present disclosure, a plurality of antenna elements may be associated with a respective (e.g., first, second or third) panel by being attached to said panel and / or arranged in parallel with said panel. The respective panel may be planar. The respective panel may comprise or consist of a (e.g., metallic and / or planar) reflector for the associated plurality of antenna elements. In accordance with the present disclosure, a plurality of antenna elements may be arranged in a matrix or periodic pattern to form an (e.g., first, second or third) antenna array. The main radiation direction of a given (e.g., first, second or third) antenna array may be perpendicular to the panel associated with the plurality of antenna elements forming said given antenna array. The main radiation direction of a given (e.g., first, second or third) antenna array may correspond to a main radiation direction of one, two or more, or all of the antenna elements forming said given antenna array. The main radiation direction of a given (e.g., first, second or third) antenna array may correspond to a direction of a main lobe and / or main beam (e.g., directed to 0° azimuth and 0° elevation) of said given antenna array.

[0014] The MPAU may further comprise a plurality of third antenna elements associated with a third panel and forming a third antenna array arranged within the housing, the third antenna array having a third main radiation direction. The third panel may be arranged oblique relative to the first panel and the second panel. The third main radiation direction may be oblique to the first main radiation direction and the second main radiation direction.

[0015] Each of the antenna arrays of the MPAU may be associated with a spatial sector (e.g., enable transmission of wireless signals to said spatial sector and / or reception of wireless signals from said sector). The sectors may differ between two or more of the antenna arrays of the MPAU. The wireless signals may be electromagnetic signals and / or communication signals. The MPAU may be configured to cover a plurality of spatial sectors (e.g., exactly two or exactly three sectors). In this case, the MPAU may be referred to as a dual-sector MPAU or a triple-sector MPAU.

[0016] For example, the first panel and the second panel, and optionally also the third panel, extend in parallel to an alignment axis of the MPAU. The alignment axis may extend in a gravity direction (e.g., when the MPAU is mounted to the mounting structure). In other words, the MPAU may be configured to be mounted to the mounting structure such that the alignment axis extends in the gravity direction. The gravity direction may correspond to an elevation direction of the first antenna array and the second antenna array. The third panel may be arranged perpendicular relative to the first panel and the second panel. The third main radiation direction may be perpendicular to the first main radiation direction and the second main radiation direction.

[0017] The first panel and the second panel may be arranged back-to-back. The plurality of first antenna elements may be arranged on or over a first (e.g., front) surface of the first panel, and the plurality of second antenna elements may be arranged on or over a first (e.g., front) surface of the second panel. A second (e.g., back) surface of the first panel may face a second (e.g., back) surface of the second panel. The first panel may be offset from the second panel (e.g., in a direction normal to a surface of the first and / or the second panel). For example, the first panel is spaced apart from the second panel by a predefined area.

[0018] At least a portion of the third panel may be arranged between the (e.g., second surface of the) first panel and the (e.g., second surface of the) second panel. For example, the entire third panel is arranged between the first panel and the second panel.

[0019] The predefined area may be bordered by (e.g., at least) the first panel, the second panel and the third panel. The predefined area may have the shape of a prism, for example a prism having a rectangular base. Three sides of the base may be formed by the first panel, the second panel and the third panel.

[0020] The first antenna array may be configured to operate at a first operating frequency or frequency band and the second antenna array may be configured to operate at a second operating frequency or frequency band. The third antenna array may be configured to operate at a third frequency or frequency band. At least one of the first and the second operating frequency or frequency band may be higher than the third operating frequency or frequency band. For example, the first operating frequency or frequency band corresponds to the second operating frequency or frequency band. For example, the first antenna array is configured as a transmission, Tx, array while the second antenna array is configured as a reception, Rx, array. The first antenna array and the second antenna array may be configured to operate in a full-duplex mode at the same time. The third antenna array may be configured to operate according to a time division duplex, TDD, mode or a frequency division duplex, FDD, mode. The MPAU may further comprise a cooling arrangement. At least one part of the cooling arrangement may be arranged in the predefined area. The at least one part may be arranged in a topmost portion of the predefined area (e.g., relative to a gravitational direction, in particular when the MPAU is mounted to the mounting structure). The cooling arrangement may comprise at least one cooling channel configured to be filled with cooling fluid. The at least one cooling channel may extend at least in part within the predefined area. The at least one cooling channel may extend entirely within the predefined area. The at least one cooling channel may be comprised in the at least one part of the cooling arrangement. The cooling arrangement may comprise a passive cooling unit (e.g., comprised in the at least one part of the cooling arrangement) such as cooling fins and / or an active cooling unit (e.g., comprised in the at least one part of the cooling arrangement) such as a fan. The at least one cooling channel may be formed by a free space between components (e.g., one or more of the panels, the housing, at least one radio unit and / or a signal processing unit) of the MPAU. The at least one cooling channel may be configured to be filled with cooled air. Alternatively, or in addition, the at least one cooling channel may be fluidly connected to an exterior of the housing.

[0021] The MPAU may further comprise a signal processing unit. The signal processing unit may be at least partially arranged within the predefined area. The signal processing unit may be configured to receive digital signals, process said digital signals and control one or more of the antenna elements to emit an electromagnetic signal based on the processed digital signals. The signal processing unit may be configured for Lower-Layer signal processing (e.g., layer 1 and / or layer 2 of the 4G or 5G standard). The signal processing unit may be arranged in a lowermost portion of the predefined area (e.g., relative to a gravitational direction, in particular when the MPAU is mounted to the mounting structure).

[0022] The at least one part of the cooling arrangement, for example the at least one cooling channel, may be arranged between the topmost portion and the lowermost portion.

[0023] The MPAU may further comprise at least one radio unit selected from a first radio unit associated with the first antenna array and a second radio unit associated with the second antenna array. At least a part of the at least one radio unit may be arranged within the predefined area. The at least one radio unit may comprise one or more amplifiers for signals to be transmitted by the associated antenna array and / or to be received by the associated antenna array. The at least one radio may be communicatively coupled to and / or controlled by the signal processing unit. The at least one radio unit may be arranged adjacent and / or parallel to its associated antenna array.

[0024] The cooling channel may be bordered by a surface of the at least one radio unit and / or a surface of the signal processing unit.

[0025] The housing may have a circular or elliptical cross-section (e.g., in a plane normal to the gravitational direction and / or normal to the first panel). The housing may comprise a radome for one or more of the antenna arrays of the MPAU. The housing may comprise a common radome for all antenna arrays of the MPAU. The housing may comprise a mounting assembly configured to side-mount the MPAU to the mounting structure. The mounting assembly may be arranged in an area between two parallel planes in which planes the (e.g., first or second surfaces of) the first panel and the second panel lie. The mounting assembly may be arranged at a location opposite from the third main radiation direction. The mounting assembly may be arranged at a location not covered by the first, second or third main radiation direction.

[0026] According to a second aspect, an antenna system (AS) is provided. The AS comprises at least one MPAU according to the first aspect. The AS further comprises the mounting structure, wherein the at least one MPAU is side-mounted to the mounting structure.

[0027] The mounting structure may comprise or be an antenna mast. The mounting structure may comprise or be a building. The at least one MPAU may be mounted laterally to the mounting structure. The at least one MPAU may be mounted such that its housing is offset from a longitudinal axis of the mounting structure. The at least one MPAU may be mounted to the mounting structure such that its first panel and its second panel extend laterally away from the mounting structure. The at least one MPAU may be mounted to the mounting structure such that the mounting structure extends along (e.g., parallel to) the first and / or the second panel of the at least one MPAU. The at least one MPAU may be mounted to the mounting structure such that the mounting structure extends along (e.g., parallel to) at least a part of a length of first and / or the second panel of the at least one MPAU. For example, the mounting structure (e.g., an antenna mast) extends parallel to the alignment axis. The mounting structure may be offset from the alignment axis. A plurality of the at least one MPAU may be arranged such that two or more (e.g., all) of the first panels and / or two or more (e.g., all) of the second panels are oblique relative to one another. A (e.g., the) plurality of the first panels and / or a (e.g., the) plurality of the second panels may be arranged around a common system axis of the multi-unit antenna system. The common system axis may extend parallel to the alignment axes. The common system axis may be offset from the alignment axes. The MPAUs may be circumferentially distributed around the common system axis. The MPAUs may be equally (e.g., periodically) distributed around the common system axis. The AS may comprise a maximum of k MPAUs, spaced apart from one another by 360° / ^ in a circumferential direction around the common system axis, wherein Xrmay correspond to an odd number larger than 1, for example 3. The MPAUs may be arranged such that the first panels and / or the second panels extend radially away from the common system axis. Each of the MPAUs may be arranged such that the first panel and the second panel of the respective MPAU are parallel to a (e.g., MPAU-specific) plane extending radially away from the common system axis.

[0028] The AS may be configured such that spatial coverage sectors of two or more of the antenna arrays overlap one another. The two or more of the antenna arrays may be part of different ones of the plurality of MPAUs. The two or more antenna arrays associated with a common overlapping spatial coverage sector may be configured to operate in a full-duplex mode. For example, a first antenna array of a first MPAU of the AS, associated with a first spatial coverage sector, may be configured to operate as a Tx antenna array, while a second antenna array of a second MPAU of the AS, associated with a second spatial coverage sector at least partially overlapping the first spatial coverage sector, may be configured to operate as a Rx antenna array (e.g., in a coordinated manner together with the first antenna array). The signal processing unit of one or more MPAUs, or a separate inter-MPAU processing unit of the AS, may control the involved antenna arrays accordingly.

[0029] SHORT DESCRIPTION OF THE FIGURES

[0030] Examples in accordance with the technique disclosed herein are explained below with reference to the figures, wherein:

[0031] Figs, la-lc schematically illustrate front, side and top views of a first exemplary MPAU in accordance with the present disclosure; Figs. 2a-2c schematically illustrate front, side and top views of a second exemplary MPAU in accordance with the present disclosure;

[0032] Figs. 2d schematically illustrates a top view of a variant of the second exemplary MPAU;

[0033] Figs. 3a schematically illustrates interior components of a third exemplary MPAU in accordance with the present disclosure;

[0034] Figs. 3b schematically illustrates a housing of the third exemplary MPAU in accordance with the present disclosure;

[0035] Fig. 4 schematically illustrates a first exemplary antenna system in accordance with the present disclosure; and

[0036] Fig. 5 schematically illustrates a second exemplary antenna system in accordance with the present disclosure.

[0037] DETAILED DESCRIPTION

[0038] Unless indicated otherwise, the reference signs used in the following denote the same or similar structural or functional features. In case an example shows more than one instance of a given entity, which entity is denoted with reference numeral "X", these instances may be referred to either as "X", or as "X- / / 7with n indicating the particular instance.

[0039] Figs, la-lc schematically illustrate front, side and top views of a first exemplary MPAU 100 in accordance with the present disclosure. The MPAU 100 is configured to be side-mounted to a mounting structure such as an antenna mast 2. The y-direction corresponds to the gravitational direction of the mounted MPAU 100 and at the same time to a longitudinal direction of the antenna mast 2.

[0040] The MPAU 100 comprises a housing 4 and a plurality of first antenna elements 6 associated with a first panel 8 and forming a first antenna array 10 arranged within the housing 4. The first panel 8 may comprise or be configured as a reflector for the plurality of first antenna elements 6. Each of the first antenna elements 6 may be a dual-polarized radiator comprising 2 dipoles or other radiating elements such as patches, cavities or other dual-polarised radiator forms, simplified in the figures in the form of an "X". The first antenna array 10 has a first main radiation direction 12 that extends essentially normal to a first surface 14 of the first panel 8.

[0041] The MPAU 100 further comprises a plurality of second antenna elements 16 associated with a second panel 18 and forming a second antenna array 20 arranged within the housing 4. The second antenna array 20 has a second main radiation direction 22. As can be seen, the first panel 8 and the second panel 18 are arranged in parallel, namely parallel to the y-z-plane. The first main radiation direction 12 is opposite to the second main radiation direction 22. As with the first antenna array 10, the second antenna elements 16 are arranged above a first surface 24 of the associated panel 18. One may say that the two panels 8, 18 are arranged back-to- back, with their second surfaces 26, 28 facing one another and that the two panels 8, 18 extend parallel to an alignment axis 30 of the MPAU 100. The alignment axis 30 is parallel to the y-axis.

[0042] The first and the second antenna array may be configured to operate at a high- frequency band, in particular a microwave frequency band (e.g., above 3 GHz). In one example, the first antenna arrays are associated with a first operating frequency band at 1800 MHz and the second antenna arrays with a second operating frequency band at 2100 MHz.

[0043] As can be seen in Figs, la and lc, the first panel is spaced apart from the second panel by a predefined area 32. This predefined area is used to arrange additional components therein. In particular, the MPAU 100 may comprise a cooling arrangement 34 including an active cooling unit 36 and a cooling channel 38, both being arranged within the predefined area 32 between the two second surfaces 26, 28. The active cooling unit 36 may be arranged in a topmost portion of the predefined area 32. The cooling channel 38 is for example air-filled. The air within the cooling channel 38 may be cooled by the active cooling unit 36.

[0044] The cooling arrangement 34 may be adapted according to the requirements of the antenna arrays of the MPAU 100. For high-power implementations, a combination of active and passive cooling techniques might be necessary, e.g., convection fins and cooling fans. By contrast, simpler solutions (e.g., solely using the cooling channel 38) might be enough for low-power MPAUs. In both cases, the proposed architecture allows for a "chimney"-like heat dissipation solution in the form of the cooling channel 38 that offers good heat convection properties. The MPAU 100 may further comprise a signal processing unit 40 that is arranged within the predefined area. In the illustrate example, the signal processing unit 40 is arranged in a lowermost portion of the predefined area 32. The cooling channel 38 can be arranged to cool the signal processing unit 40.

[0045] The MPAU may further comprise a first radio unit 42 associated with the first antenna array 10 and a second radio unit 44 associated with the second antenna array 20. Each of the radio units 42, 44 may be arranged within the predefined area 32, for example adjacent and parallel to the associated panel 8, 18. The cooling channel is bordered by a surface of the radio units 42, 44 and the signal processing unit 40 and, thus, can cool each of these components.

[0046] Figs. 2a-2c schematically illustrate front, side and top views of a second exemplary MPAU 200 in accordance with the present disclosure.

[0047] In addition to the components discussed for the MPAU 100, the MPAU 200 further comprises a plurality of third antenna elements 48 associated with a third panel 50 and forming a third antenna array 52 arranged within the housing 4, the third antenna array 52 having a third main radiation direction 54. The third panel 50 is arranged perpendicular relative to the first panel 8 and the second panel 18, and the third main radiation direction 54 is perpendicular to the first main radiation direction 12 and the second main radiation direction 22. All panels 8, 18, 50 extend in parallel to the alignment axis 30. It is also possible for the third panel 50 to be tilted such that the third main radiation direction is non-parallel to the z-direction (e.g., extends into the negative y-direction).

[0048] It is also possible to use passive antenna elements as the antenna elements of the third antenna array and thus configure the first antenna array as a non-active antenna array.

[0049] As can be seen, the third panel 50 is arranged between the two second surfaces 26, 28 of the panels 8, 18. One may thus say that the predefined area 32 is bordered or defined by the second surfaces 26, 28 and the second surface 58 of the third panel 50 having first surface 56 and second surface 58.

[0050] In difference to first and second antenna arrays 10, 20, the third antenna array 52 may be configured to operate at a low-frequency band, in particular a radio-wave frequency band (e.g., below 3 GHz). As apparent from the two variants of the MPAU 200 shown in Fig. 2c and 2d, the position of the third panel 50 between the panels 8, 18 in the z-direction can be chosen such that the third radiators 48 are arranged outside the panels 8, 18 (Fig. 2c) or between the panels 8, 18 (Fig. 2d). In the option of Fig. 2d, the outer panels 8, 18 with the radiators 6, 16 may provide a shielding effect and / or be configured as (e.g., part of) a reflective sidewall for the radiators 48 of the third antenna array 52.

[0051] Figs. 3a schematically illustrates interior components of a third exemplary MPAU 300 in accordance with the present disclosure. In this example, the third panel 52 is arranged as in Fig. 2c. In addition to the components described for the MPAU 100 and 200, the MPAU 300 comprises a mounting assembly 58 comprising two attachment rods 60-1, 60-2 extending in the z-direction toward the mounting structure, for example the antenna mast 2. The mounting assembly 54 is located such that it is outside the field of view of each antenna array of the MPAU 300. This may enable a side-mounting of the MPAU 300 without negatively impacting signal transmission due to shielding and / or scattering of signals by the mounting assembly 54 and the mounting structure.

[0052] In this example, the two antenna arrays 6, 16 may be configured to operate at a frequency of 3.5 GHz. Each antenna array may contain 16*4 radiators with 0.72 vertical separation and 0.52 horizontal separation. This setup allows, for example, each array to operate in 64T64R MIMO by arranging the radiators into an 8x4 array of 2x1 sub-arrays in dual-polarized mode. This allows offering two 64T64R units as a single unit in the form of the MPAU.

[0053] Figs. 3b schematically illustrates a housing 4 of the third exemplary MPAU 300 in accordance with the present disclosure. The housing 4 may be formed of a water- resistant material that is transparent for electromagnetic radiation at the operating frequencies of the antenna arrays 6, 16, 52 housed therein. In other words, the housing 4 may be configured as a radome for the antenna arrays 6, 16, 52. In this example, the housing 4 has an elliptical cross-section in the x-z-plane. This may reduce wind drag and prevent signal scattering induced by abrupt angles of the housing surface. Exemplary values of the dimensions a, b and c indicated in Figs. 3a and 3b are a = 52cm, b = 30cm and c = 120cm, but the present disclosure is not limited thereto. These dimensions are reasonable for typical urban and rural sites. The Figure also illustrates at the top part of the MPCU 300 some cooling fins as part of the cooling arrangement 34 and an elliptic cylinder-shaped radome as (e.g., part of) housing 4. Cabling could be connected to the bottom part of the MPAU, in particular to the signal processing unit 40.

[0054] Fig. 4 schematically illustrates a first exemplary antenna system 1000 in accordance with the present disclosure. The AS 1000 comprises three MPAUs 300-1 to 300-3. It is also possible for the AS 1000 to instead comprise three MPAUs 100 or 200. In the illustrated example, each MPAU 300 is configured according to the option of Fig. 2d such that the third panel 50 is disposed between the first and the second panel 8, 18.

[0055] The three MPAUs 300-1 to 300-3 are arranged in equal intervals, in a rotation- symmetrical manner around a common system axis 61 that in the illustrated example corresponds to the longitudinal axis of the antenna mast 2. The first and second panels 8, 18 may lie parallel to an alignment plane in which the common system axis 61 lies. One may say that the panels 8, 18 extend essentially radially away from the antenna mast 2. The third main radiation direction 54 points radially away from the antenna mast 2. The first and second main radiation directions 12, 22 do not intersect the antenna mast 2 either. This means that wireless signals can be emitted by each antenna array 6, 16, 52 without being disturbed by the mounting assembly 58 or the mounting structure.

[0056] Each antenna array 6, 16, 52 of the MPAUs 300-1 to 300-3 is associated with a spatial coverage sector. In the illustrated example, coverage sectors of pairs of antenna arrays overlap one another. Such a pair of antenna arrays consists of a first antenna array 6 of a first MPAU 300 and a second antenna array 16 of an adjacent second MPAU 300. The pair of antenna arrays may be configured to operate in a full- duplex mode. In Fig. 4, areas in which the spatial coverage sectors overlap one another are indicated with dashed lines as 62-1, to 62-3. On the other hand, the spatial coverage sectors 64-1 to 64-3 of the third antenna arrays 52 do not overlap sectors of the first or second antenna arrays 6, 16 of the MPAUs of the AS 1000, although the present disclosure is not limited thereto.

[0057] The AS 1000 enables a compact arrangement of nine or more antenna arrays around a given antenna mast 2, while providing a large spatial coverage and reliable functionality of AS 1000. The AS 1000 or 2000 may be configured such that each antenna array has a maximum beamforming angle of 30° in azimuth. This may minimize the resulting sidelobes and thus reduce interference to other communication signals.

[0058] The AS 1000 or 2000 may be configured with 6 sectors with overlapping coverage and with azimuth ± 60 degrees maximum beamforming angle per sector. This may allow! a coordinated multi-point (CoMP) communication and / or multiple transmission point (mTRP) communication as defined in the 3GPP 4thgeneration or 5thgeneration standard. This implementation may also improve coverage, cell-edge throughput, and / or system efficiency. Depending on the traffic demands, the C-RAN deployment may adapt itself to serve uplink and / or downlink channels.

[0059] Fig. 5 schematically illustrates a second exemplary AS 2000 in accordance with the present disclosure. Again, the AS 2000 comprises three MPAUs 300-1 to 300-3 arranged as described for the AS 1000. In the illustrated example, it can be seen that each MPAU 300 may be attached to the same antenna mast 2 via its mounting assembly 58 and each alignment axis 30 may be parallel to the longitudinal axis of the antenna mast 2. The attachment rods 60 may thus extend radially away from the antenna mast 2. The housings 4 having elliptical cross-sections in the respective x-z- planes, with the shorter middle axis of the ellipse pointing radially away from the longitudinal axis of the antenna mast 2. Exemplary values of the dimensions d-g indicated in Fig. 5 are d = 76,5cm, e = 186 cm, f = 120cm and g = 100cm, but the present disclosure is not limited thereto.

[0060] Generally speaking, for outdoor rural, urban or suburban coverage, multiple sectors may be served by an antenna system to provide coverage. There is a space and load limitation per site and antenna mast, limiting the number of antennas. Multi-band antenna panels may be used as antenna arrays disclosed herein to challenge the size and cost problems, for example to cover both a low-band and a low mid-band, and possibly configured to be transparent at a C-band.

[0061] The proposed antenna architecture makes use of a back-to-back arrangement of panels within the same radome enclosure for transmitting and receiving of signals via antenna arrays facing into opposite directions. Obstruction and reflection from the antenna mast is avoided by rotating and mounting the antenna panels by 90 degrees horizontally (in azimuth). The present disclosure provides for a single antenna solution that supports both 3 and 6 sector deployments while keeping the antenna gain and limiting the side lobe level. Flexible horizontal sector coverage configurations allow for different transmission modes in combination with beamforming. The novel mechanical layout allows for a compact footprint and advanced heat dissipation.

[0062] The present technique allows for a low footprint and cost of the antenna system, while achieving the desired sectorization. The particular arrangement of the antenna arrays takes into account that the gain of the antenna main beam may decrease at larger azimuth angles while the sidelobe level increases. In difference to known solutions, this means that the interference of sidelobes to adjacent services can be reduced. Besides this, the AS disclosed herein allows for coherent joint transmission and reception techniques to serve overlapping sectors. Compared with solutions in which a folded reflector surface is used, the present technique improves isolation between the panels and makes clear from a deployment and sector coverage where overlapping occurs. The mounting of the MPAU is also simplified. The MPAUs disclosed herein can be used for multi-sector deployments, and are not limited to a particular number of sectors. The integration of cooling arrangement, radio units and signal processing units allows for a compact building size of the MPAUs.

[0063] Various modifications of the technique disclosed herein are possible. For instance, an AS comprising more than three MPAUs may be provided, or additional antenna arrays (e.g., associated with the first, second or third panel) may be added to the MPAUs described herein. Further modifications and advantages may be apparent to those skilled in the art.

Claims

CLAIMS1. A multi-panel antenna unit (100; 200; 300) configured to be side-mounted to a mounting structure (2), the multi-panel antenna unit (100; 200; 300) comprising: a housing (4); a plurality of first antenna elements (6) associated with a first panel (8) and forming a first antenna array (10) arranged within the housing (4), the first antenna array (10) having a first main radiation direction (12); and a plurality of second antenna elements (16) associated with a second panel (18) and forming a second antenna array (20) arranged within the housing (4), the second antenna array (20) having a second main radiation direction (22), wherein the first panel (8) and the second panel (18) are arranged in parallel, and wherein the first main radiation direction (12) is opposite to the second main radiation direction (22).

2. The multi-panel antenna unit (100; 200; 300) of claim 1, further comprising: a plurality of third antenna elements (48) associated with a third panel (50) and forming a third antenna array (52) arranged within the housing (4), the third antenna array (52) having a third main radiation direction (54), wherein the third panel (50) is arranged oblique relative to the first panel (8) and the second panel (18), and wherein the third main radiation direction (54) is oblique to the first main radiation direction (12) and the second main radiation direction (22).

3. The multi-panel antenna unit (100; 200; 300) of claim 2, wherein the first panel (8), the second panel (18) and third panel (50) extend in parallel to an alignment axis (30) of the multi-panel antenna unit (100; 200; 300).

4. The multi-panel antenna unit (100; 200; 300) of claim 3, wherein the alignment axis (30) extends in a gravity direction (y).

5. The multi-panel antenna unit (100; 200; 300) of any one of claims 2 to 4, wherein the third panel (50) is arranged perpendicular relative to the first panel (8) and the second panel (18), and wherein the third main radiation direction (54) is perpendicular to the first main radiation direction (12) and the second main radiation direction (22).

6. The multi-panel antenna unit (100; 200; 300) of any one of claims 1 to 5, wherein the first panel (8) is spaced apart from the second panel (18) by a predefined area (32).

7. The multi-panel antenna unit (100; 200; 300) of at least claim 2, wherein at least a portion of the third panel (50) is arranged between the first panel (8) and the second panel (18).

8. The multi-panel antenna unit (100; 200; 300) of claims 6 and 7, wherein the predefined area (32) is bordered by the first panel (8), the second panel (18) and the third panel (50).

9. The multi-panel antenna unit (100; 200; 300) of at least claim 2, wherein the first antenna array (10) is configured to operate at a first operating frequency, the second antenna array (20) is configured to operate at a second operating frequency, and the third antenna array (52) is configured to operate at a third frequency, wherein at least one of the first and the second operating frequency is higher than the third operating frequency.

10. The multi-panel antenna unit (100; 200; 300) of claim 9, wherein the first operating frequency corresponds to the second operating frequency.

11. The multi-panel antenna unit (100; 200; 300) of at least claim 6, further comprising a cooling arrangement (34), wherein at least one part of the cooling arrangement (34) is arranged in the predefined area (32).

12. The multi-panel antenna unit (100; 200; 300) of claim 11, wherein the at least one part is arranged in a topmost portion of the predefined area (32).

13. The multi-panel antenna unit (100; 200; 300) of claim 11 or 12, wherein the cooling arrangement (34) comprises at least one cooling channel (38) configured to be filled with cooling fluid, the at least one cooling channel (38) extending at least in part within the predefined area (32).

14. The multi-panel antenna unit (100; 200; 300) of claim 13, wherein the at least one cooling channel (38) extends entirely within the predefined area (32).

15. The multi-panel antenna unit (100; 200; 300) of claim 13 or 14, wherein the at least one cooling channel (38) is configured to be filled with cooled air and / or is fluidly connected to an exterior of the housing (4).

16. The multi-panel antenna unit (100; 200; 300) of at least claim 6, further comprising a signal processing unit (40), at least partially arranged within the predefined area (32).

17. The multi-panel antenna unit (100; 200; 300) of claim 16, wherein the signal processing unit (40) is arranged in a lowermost portion of the predefined area (32).

18. The multi-panel antenna unit (100; 200; 300) of claim 17 and at least claim 12, wherein the at least one part of the cooling arrangement (34) is arranged between the topmost portion and the lowermost portion.

19. The multi-panel antenna unit (100; 200; 300) of at least claim 6, further comprising at least one radio unit (42; 44) selected from a first radio unit (42) associated with the first antenna array (10) and a second radio unit (44) associated with the second antenna array (20), wherein at least a part of the at least one radio unit (42; 44) is arranged within the predefined area (32).

20. The multi-panel antenna unit (100; 200; 300) of claim 19, wherein the at least one radio unit (42; 44) is arranged adjacent and / or parallel to its associated antenna array (10; 20).

21. The multi-panel antenna unit (100; 200; 300) of any one of claims 1 to 20, wherein the housing (4) has a circular or elliptical cross-section.

22. An antenna system (1000; 2000) comprising: at least one multi-panel antenna unit (100; 200; 300) according to any one of claims 1 to 21; and a mounting structure (2), wherein the at least one multi-panel antenna unit (100; 200; 300) is side- mounted to the mounting structure (2).

23. The antenna system (1000; 2000) of claim 22 with the at least one multipanel antenna unit (100; 200; 300) according to at least claim 3, wherein themounting structure (2) is an antenna mast extending parallel to the alignment axis (30).

24. The antenna system (1000; 2000) of claim 22 or 23, wherein a plurality of the at least one multi-panel antenna unit (100; 200;300) are arranged such that two or more of the first panels (8) and / or two or more of the second panels (10) are oblique relative to one another.

25. The antenna system (1000; 2000) of claim 24, wherein a plurality of the first panels (8) and / or a plurality of the second panels (10) are arranged around a common system axis (61) of the antenna system (1000; 2000).

26. The antenna system (1000; 2000) of claim 25 with the plurality of the at least one multi-panel antenna unit (100; 200; 300) according to at least claim 3, wherein the common system axis (61) extends parallel to the alignment axes (30).

27. The antenna system (1000; 2000) of claim 25 or 26, wherein the multi-panel antenna units (100; 200; 300) are circumferentially distributed around the common system axis (61).

28. The antenna system (1000; 2000) of claim 27, wherein the multi-panel antenna units (100; 200; 300) are equally distributed around the common system axis (61).

29. The antenna system (1000; 2000) of any one of claims 25 to 28, wherein the multi-panel units (100; 200; 300) are arranged such that the first panels (8) and / or the second panels (10) extend radially away from the common system axis (61).

30. The antenna system (1000; 2000) of any one of claims 24 to 29, configured such that spatial coverage sectors (61) of two or more of the antenna arrays (8; 10; 52) overlap one another.

31. The antenna system (1000; 2000) of claim 30, wherein the two or more of the antenna arrays (10; 20; 52) are part of different ones of the plurality of multi-panel antenna units (100; 200; 300).

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