Antenna front end module for an active antenna array

Abstract

The present invention relates to an antenna front end module (100) for an active antenna array, to an active antenna array and to a base station including said array The antenna front end module (100) comprises an antenna element (110) and a front end element (140), wherein the antenna element (110) includes at least one wave guide feed (114), at least one radio- frequency waveguide (112), and at least two apertures (112a, 112b). Further, the radio-frequency waveguide includes a wave guide harness element that connects the wave guide feed (114) with the at least two apertures (112a, 112b). The apertures (112a, 112b) are open ended waveguide apertures of the at least one radio-frequency waveguide (112) or horn radiators. Further, the front end element (140) is connected to the at least one wave guide feed (114) for receiving and / or transmitting radio-frequency signals.

Description

[0001] ANTENNA FRONT END MODULE FOR AN ACTIVE ANTENNA ARRAY

[0002] Technical Field

[0003] The present invention generally relates to radio communication and, more particularly to an antenna front end module for an active antenna array, to an active antenna array including at least two antenna front end modules and to a base station including the active antenna array. The base station may be a base station for mobile communications.

[0004] Background

[0005] Base stations and in particular base station antennas for mobile communication systems tend to become more complex due to the ongoing integration of a high number of active components, such as amplifiers and filters. Further, oftentimes antenna arrays are used, which have to be controlled for effective transmitting and receiving of signals. For example, antennas in the field of massive MIMO must support two-dimensional antenna arrays, having multiple columns.

[0006] A reason for an increase of complexity can also be found in the increasing number of different frequency bands that have to be supported by a typical base station antenna, i.e. within in a single housing. Present antennas are designed to receive and to transmit signals in multiple frequency bands in a frequency range between 400 MHz and 10 GHz. Regarding the upcoming 5th generation mobile communication standards, additional frequency bands will be utilized, which employ frequencies up to 100 GHz.

[0007] Known antennas therefore utilize multiple subarrays of antenna elements to operate the required, but different frequency bands. Complexity is particularly high, when it comes to high frequency band arrays, e.g. supporting frequency bands from 3400 MHz to 3800 MHz, from 5.1 GHz to 5.8 GHz or from 10 GHz to 14 GHz. Those arrays are typically controlled by a high number of individual transceivers, which are configured for controlling individual radiator elements of the array. Nevertheless, higher frequency band antennas are oftentimes realized as (single) antenna array, which can be integrated into a housing accommodating additional antenna (sub)arrays for lower bands, e.g. in a stacked configuration. Alternatively, low band radiators can be arranged in an interleaved manner.

[0008] The huge number of integrations of electronic components leads to very complex arrangements. Hence, those antennas and antenna arrays are difficult to manufacture.

[0009] US patent application no. US 2021 / 0 336 659 Al suggests a multipleinput multiple-output (MIMO) antenna, having a stacked structure. Nonetheless, the suggested design still requires a high number of interconnections between different stacked layers and components, bearing a high risk of misalignment and / or malfunction.

[0010] KR 2021 / 0 151 698 A suggests also a multiple input / output antenna device. More particularly, the antenna device includes a main board in which an accommodation space is formed in at least one area in the form of a predetermined space, and a sub-board which is stacked on the rear side of the main board. Components, such as filters and the amplifiers are arranged as an array in a stacked manner. However, wiring and interconnecting is still complex.

[0011] WO 2023 / 051 471 Al relates to a feed system for a base station antenna serving different frequency bands.

[0012] However, these antennas are limited with respect to the number of usable frequency bands and / or are very complex to manufacture (particularly due the high number of interconnections.

[0013] Summary

[0014] In view of the above, an object of the present invention is to provide an antenna array which is easy to manufacture and that is suited for being integrated in a multiband antenna structure. The object is achieved by an antenna front end module for an active antenna array according to claim 1, by an active antenna array according to claim 13 and by a base station according to claim 20. Further aspects of the invention are given in the dependent claims, as well as in the following description.

[0015] In particular, the object is achieved by an antenna front end module for an active antenna array. Multiple (at least two) antenna front end modules can be combined to form an active antenna array. The active antenna array can serve for mobile communications, such as MIMO applications, e.g. in a base station.

[0016] The antenna front end module comprises an antenna element and a front end element. The antenna element may be a passive element, wherein the front end element may include active components.

[0017] In an aspect, the front end element may be, or may comprise a transceiver, TRx, component, which may be mounted on a carrier printed circuit board, PCB. The TRx component may include active components such as a transmitting amplifier, a receiving amplifier, at least one switch for time-division-duplexing, TDD, operations and / or at least one fast switch for TDD mode RX / TX control. Further components providing additional functionalities may be provided, such as a temperature sensor, a gain control (AGC), a phase shifter (in order to adjust the phase shift of received and / or transmitted signals), at least one DC / DC converter (in order to adapt the power supply) and / or components of a DPD (Digital Predistortion), CFR (Crest Factor Reduction) and / or calibration. Further components such as may also be present.

[0018] The antenna element includes at least one wave guide feed, at least one radio-frequency waveguide and at least two apertures. The apertures may be arranged so as to provide a first polarization (e.g. + 45°). Alternatively, the apertures may be arranged to provide a dual polarization (e.g. ±45°). The radio-frequency waveguide includes a wave guide har- ness element that connects the wave guide feed with the at least two apertures. Hence, a wave guide feed is connected with multiple (at least two) apertures.

[0019] The apertures are open ended waveguide apertures of the at least one radio-frequency waveguide, horn radiators and / or the like.

[0020] Further, the front end element is connected to the at least one wave guide feed for receiving and / or transmitting radio-frequency signals.

[0021] In a particular aspect, one front end element may be assigned to one antenna element. However, it is also possible that one front end element is assigned to multiple antenna elements. In this case, the front end element can include multiple input / output elements for connecting to the respective wave guide feeds of the multiple antenna elements. In a further aspect, an antenna element may include multiple wave guide feeds, wherein each feed is connected to a respective one of front end elements.

[0022] In an even further aspect, the antenna element may include a waveguide power splitter.

[0023] Using a waveguide, and in particular a wave guide harness element and / or a waveguide power splitter, allows to connect the front end ele- ment(s) to the antenna element(s) with very little losses. Thus, energy can be effectively saved. Further, the connection is very reliable, so that malfunction can be effectively prevented.

[0024] For example, an input / output element for connecting the front end element to a wave guide feed may be an electrically conductive pin (feeder pin), which pin can be fit, particularly press fit, into the wave guide feed. The electrically conductive pin may be connected to a PCB of the front end element by soldering, bonding, welding and / or the like. In a particular aspect, the electrically conductive pin may include or may be connected to a via of the PCB. The front end element may further be connected to the antenna element so as to be thermally coupled. Thus, heat generated by the (active) front end element can be dissipated by the (passive) antenna element. In a particular aspect, the antenna element may be thermally coupled to the front end element using a thermal conductive pad, or thermal conductive paste and / or a thermal conductive adhesive.

[0025] Further, the antenna element may include an array of open ended waveguide apertures or horn radiators. The array may include at least 2, or at least 4 or at least 6, or at least 8, or at least 20, or at least 80 open ended waveguide apertures or horn radiators. Those apertures or horn radiators may be arranged in rows and columns, e.g. in a 1x2 (one row, two columns), a 1x3, a 1x4, a 1x5, a 1x6, ..., a 2x2, a 2x4, a 2x6, ... or a 4x40 configuration. For example, the array may have 1 to 40 columns and 1 to 4 rows.

[0026] It has been found, that multiple apertures (each acting as radiator), which may be open ended waveguide apertures or horn radiators, can be combined to achieve an increased antenna gain. For example, four apertures (radiators) may form an array, having a higher gain compared with a single radiator. When choosing the number of connected apertures, the compromise has to be considered between a desired beam steering angle (which is limited by an achievable focus beam), and the additional gain of the array.

[0027] The distance between apertures being connected to the same wave guide feed may be in a range of 0.2 A to 0.8 A, or in a range of 0.4 A to 0.7 A, or in a range of 0.55 A to 0.65 A, wherein A denotes the wavelength of the frequency band of the antenna element.

[0028] The wave guide may be a low-loss wave guide, connecting the feed and the different apertures (radiators) in a phase optimized manner. For example, in an antenna array, the wave guided feeds of different waveguides may be arranged in phase or with a certain phase difference to achieve a fixed down tilt in a range of e.g. 1° to 10°, or in a range of 2° stant small signal delay between neighbored apertures (radiators).

[0029] In an aspect, calibration may be required to generate a feedback signal, which is coupled out from the wave guide after the transmit amplifier. The calibration shall ensure, that the correct phases will be transmitted from the antenna elements, respectively the radiators (e.g. open ended waveguide apertures or horn radiators).

[0030] In a further aspect, the antenna element may have at least one contact face and a propagation face. The at least one contact face is configured to contact a further antenna front end module. In a particular aspect the at least one contact face may be a heat transmission surface, configured for dissipating heat generated by the antenna front end module.

[0031] Hence, heat can be dissipated via the antenna elements of an antenna array. Particularly, the contact faces allow for a proper cooling of antenna front end modules that are surrounded by two, or by at least three, or at least four antenna front end modules, when being arranged in an array.

[0032] Further, the contact face may provide for a galvanic coupling between adjacent antenna elements (i.e. there is a direct contact). In a further aspect, there may be an indirect contact for achieving a capacitive coupling. In case of a capacitive coupling, the contact face may be coated (e.g. varnished) or anodized. Further, a dielectric material, such as a plastic film, may be provided between adjacent contact faces.

[0033] The propagation face includes the at least two apertures. Thus, in an antenna array, the propagation faces of neighboring antenna elements may form a common propagation plane A. This plane may serve as a reflector for radiators having a frequency below the frequency of the apertures or horn radiators, such that the plane A acts like a Faraday mesh cage. In a particular aspect the common propagation plane A may serve as a reflector for low-band or mid-band radiators, such as dipoles.

[0034] Further, the antenna element may include a filter (at least one), particularly a high pass filter and / or a band pass filter and / or a dual-band filter and / or a multi-band filter. The at least one filter may be provided within the wave guide or connected to the wave guide (e.g. as waveguide filter or cavity filter). In a particular aspect, the at least one filter may be arranged in a receiving and / or transmitting path of the wave guide. In the TDD case, a common filter may be used for receiving and transmitting. In a frequency division duplexing, FDD case, a duplex filter may be used. In case a cavity filter is used, the filter may e.g. include 2 to 8, or 4 to 6 cavities.

[0035] The antenna front end module may be configured for receiving and / or transmitting radio-frequency signals being in a frequency range from 5 GHz to 100 GHz, particularly in a range from about 7 GHz to 15 GHz, or 24 GHz to 27.5 GHz, and / or from about 27.5 - 29.5 GHz, and / or from about 37 - 43.5 GHz. It has to be understood, that these ranges are only exemplary and that other frequency bands, as e.g. used for 5G and / or 6G communication can be implemented.

[0036] Further, the wave guide feed, the at least one radio-frequency waveguide, and the at least two apertures may be integrally formed. In a particular aspect the antenna element may be a one-piece metal element. This allows to provide a very reliable and robust antenna element. Alternatively, the antenna element may be a one-piece element having a metallized surface. Here, the antenna element may have a plastic-based or ceramic-based body, which is coated with an electrically conductive metal coating (metallized). This allows to provide a light-weight antenna element.

[0037] For example, the antenna element may be formed by an additive manufacturing technique, such as 3D-printing, or the antenna element may be injection molded or die casted, particularly pressure die casted. It is also possible to e.g. mill the antenna element.

[0038] The antenna element may be made of, or metallized with at least one of the following materials: aluminum, magnesium, titan, zinc, copper, silver, gold, chromium, nickel, beryllium, and / or an alloy thereof. For example, the antenna element may be a die-casted aluminum element. In a further aspect, the antenna element may include at least one channel for guiding a heat transfer medium, such as water. Thus, heat can be dissipated effectively. The channel may include at least one port for connecting the channel to a channel of a further, adjacent antenna element and / or for connecting the channel to a heat transfer fluid conduit.

[0039] Further, the antenna element may have a first recessed portion. The waveguide feed may be located in the first recessed portion and the first recessed portion may accommodate the front end element at least partially. Thus, a compact front end module can be provided. This allows to provide an active antenna array having a high radiator (aperture) density, and therefore a high gain.

[0040] The antenna element may have a second recessed portion. This second recessed portion may be located opposite to the front end element and may be configured to accommodate a front end element of a further antenna front end module being in contact with the at least one contact face. This allows to provide an active antenna array with a high front end module density and therefore with a high radiator (aperture) density.

[0041] Even further, the antenna element may have a third recessed portion. The third recessed portion may be designed so as to prevent shorting a feeder pin of the further antenna front end module. Thus, manufacturing of the active antenna array can be facilitated and is more reliable.

[0042] The object is further achieved by an active antenna array, which comprises at least two antenna front end modules as described above. The front end modules are arranged, e.g. side by side, so as to form an antenna array.

[0043] There may be at least one first subarray of antenna front end modules having first polarization (e.g. +45°) and a second subarray of antenna front end modules having second polarization (e.g. -45°). Hence, the active antenna array may provide for dual polarization. Further, different sub-arrays of the active antenna array may be configured to be operated at different frequency bands. The frequency bands may be in a range from 5 GHz to 100 GHz.

[0044] In the array, the antenna front end modules contact each other (directly for galvanic coupling or indirectly for capacitive coupling) at respective contact faces. Further, the antenna front end modules of the array may be arranged so that the propagation faces of the at least two antenna front end modules are aligned in a common plane A. This common plane may then serve as a reflector for further radiators, particularly low-band and / or mid-band radiators, such as dual polarized dipoles.

[0045] The active antenna array may include at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60 antenna front end modules. These modules may be arranged in rows (n) and columns (m), leading to a n x m arrangement (e.g. 4x8 or 8x8 or 6x12). The active antenna array may have 1 to 20 rows and 1 to 20 columns.

[0046] In a particular aspect, the antenna front end modules of the active antenna array may be glued and / or clamped and / or screwed to each other. Other ways of connecting the front end modules are also possible. In case the connection is reversible, such as clamping, maintenance of the antenna array in facilitated, as single antenna front end modules or subarrays can be easily exchanged in case of a malfunction.

[0047] Further, the antenna front end modules of an active antenna array may be arranged in a V-shape, wherein the propagation faces of the antenna front end modules are aligned in a common plane A. This allows to effectively prevent interferences and / or a suppression of undesired side lobes.

[0048] The active antenna array may further comprise at least one ADC-DAC- module. The ADC-DAC module may be electrically connected to at least two of the front end modules of the active antenna array. It is also possible to provide multiple ADC-DAC-modules. An ADC-DAC-module may then be connected to the front end modules forming a sub array of the active antenna array. An interface between the ADC-DAC-module and the respective front end modules may be in a digital format, which optionally enables a phase synchronized transmission. This i.e. can be based on the CPRI or eCPRI format as well as other defined inter-faces for the lower layer split as 7.1 or 7.2 according to the 3GPP or the open RAN alliance (ORAN). Depending on the implementation of the RAN functions, the interface can also be realized in the Layer 2. Additional required control and synchronization signals - as the switching control for the TDD switch - can be embedded in the data stream.

[0049] For example, each front end module may have at least four connections, including PWR (e.g. DC48V), GND, RXout and TXin. Additionally, PAe- nable and / or DigCtl may be provided. Those connections may be used for connecting the front end module with the respective ADC-DAC-module. For example, the ADC-DAC module may be electrically connected to at least two of the front end modules using a flex PCB, plug connectors (particularly a plug connector array), cables and / or other electrically connecting means. In a particular aspect, the at least four connections may include conductive paths being provided on the carrier PCB of the front end element.

[0050] Further, the active antenna array may comprise at least one heat sink element. The heat sink element may be thermally connected to at least one contact face of the front end modules. For example, the heat sink element may laterally limit the active antenna array and / or may comprise a cooling structure, such as cooling ribs.

[0051] In a further aspect the active antenna array may comprise at least one low-band and / or mid-band radiator (e.g. a dual polarized dipole). The at least one low-band and / or mid-band radiator may be arranged so that the common plane A forms a reflector for the at least one low-band and / or mid-band radiator. Thus, the active antenna array may transmit and receive signals in various frequency bands (low band, mid band, high band and / or very high band). Further, the active antenna array may comprise an amplifier module, the amplifier module may be configured to amplify a received signal and / or a signal to be transmitted. In an aspect, the amplifier module may be part of the active front end element.

[0052] The object is further achieved by a base station for mobile communications, the base station including at least one active antenna array as described above.

[0053] Brief Description of the Drawings

[0054] Different embodiments of the invention will be described in the following, by way of example and with reference to the figures. The same elements are provided with the same reference signs. The figures show in detail:

[0055] Fig. 1 a schematic view of a base station;

[0056] Fig. 2 a schematic scheme of a frontend module according to the invention;

[0057] Fig. 3 an exploded view of a frontend module according to the invention;

[0058] Fig. 4 an isometric top view of a frontend module according to the invention;

[0059] Fig. 5 an isometric bottom view of a frontend module according to the invention;

[0060] Fig. 6 a schematic view of an active antenna array according to the invention;

[0061] Fig. 7 a schematic view of a further active antenna array according to the invention, and

[0062] Fig. 8 a schematic view of a V-shaped active antenna array according to the invention.

[0063] Detailed Description Fig. 1 shows a schematic illustration of a base station 1 according to an embodiment. The base station 1 incudes a control unit 40, such as a based band unit (BBU), which is in communication with radio units 31, 32. Those radio units 31, 32 may be remote radio units, which may be remotely controlled by the control unit. The radio unit 31 is assigned to a first multi band antenna, which includes an active antenna array 10. The radio unit 32 is assigned to a second multi band antenna, which includes an active antenna array 10.

[0064] The control unit 40 is connected via respective data lines to the radio units 31, 32. Each one of the radio units 31, 32 powers a respective base station antenna (i.e. multi-band antennas 10, 20), or at least parts thereof. The base station antennas may be multi-band antennas 10, 20 as shown in Fig. 2.

[0065] Fig. 2 a schematic scheme of an antenna frontend module 100 according to the invention, showing exemplarily how single components may be arranged in the frontend module 100.

[0066] The antenna front end module 100 may be part of an active antenna array 10, as e.g. shown in Figs. 6 to 8. The antenna front end module 100 comprises an antenna element 110 and a front end element 140.

[0067] The antenna element 110 includes at least one wave guide feed 114 (cf. Fig. 3), at least one radio-frequency waveguide 112 and at least two apertures 112a, 112b. The apertures 112a, 112b are e.g. open ended waveguide apertures of the at least one radio-frequency waveguide 112 or horn radiators, and accordingly act as radiators.

[0068] The at least one wave guide feed 114, the at least one radio-frequency waveguide 112 and the apertures 112a, 112b form a waveguide network. This waveguide network may also include filters, splitters or harnesses.

[0069] The radio-frequency waveguide 112 includes a wave guide harness element that connects the wave guide feed 114 with the at least two apertures 112a, 112b, hence one wave guide feed is connected to multiple open ended wave guide apertures. Further a filter 115, e.g. a waveguide filter or a cavity filter may be provided.

[0070] The single radiators, respectively apertures 112a, 112b may be assigned to a particular frequency band (e.g. 28 GHz). Multiple apertures can be combined to achieve a higher antenna gain. In the case shown in Fig. 2 four apertures with a distance of e.g. about 0.6 wavelength (A) may be combined to a subarray. Accordingly, a higher gain compared to a single radiator can be achieved.

[0071] Further, the front end element 140 is connected to the at least one wave guide feed for receiving and / or transmitting radio-frequency signals 200. The front end element 140 comprises a control 106 (e.g. CFR, AD / DA, DPD, AGC and / or phase-control) that receives / transmits data 210 to be transmitted or that was received. Further, the front end element 140 may comprise an amplifier 104, for amplification of Rx and / or Tx signals. A TDD switch 103 allows to operate the antenna front end module 100 in TDD mode. Additional components, such as a calibration 105, a power supply 107 and / or a control and / or synchronization signal component may be provided.

[0072] The antenna frontend module 100 shown in Fig. 2 is designed for a TDD operation. The filter 115 can be used for the Tx and Rx path and may be located in the waveguide 112, e.g. directly in front of the radiating apertures 112a, 112b.

[0073] The TDD switch 103 may be a PIN diode, a transistor switch, or the like. For example, mechanical switches can also be considered.

[0074] In a particular example, the receiving amplifier 104 (Rx) will comprise a low noise amplifier. The transmit amplifier 104 (Tx) may comprise a driver amplifier stage and a power amplifier stage. The calibration 105 and a respective feedback path, allows to calibrate a phase, a gain, a magnitude at the radiator(s) and / or allows to enable linearization by means of a DPD (digital predistortion). It is to be understood, that these functions (and respective components) may be located entirely in the front end element 140 or may be spread over further components and units, such as a ADC-DAC module and / or a central control unit and / or a radio.

[0075] Fig. 3 shows an exploded view of a frontend module 100 according to the invention. The antenna front end module 100 comprises an antenna element 110 and a front end element 140. The antenna element 110 includes a wave guide feed 114, which is connected via a radio-frequency waveguide 112 with open ended waveguide apertures 112a, 112b (or horn radiators), as shown in Fig. 4.

[0076] As further shown in Fig. 4, the front end element 140 is connected to the at least one wave guide feed 114 via a feeder pin 144. The feeder pin 144 can be fit, particularly press fit, into the wave guide feed 114.

[0077] The antenna element 110, as shown in Fig. 4, includes an array of open ended waveguide apertures 112a, 112b or horn radiators. In this embodiment, the antenna element 110 includes a 1x6 array and therefore 6 apertures.

[0078] Further, the antenna element 110 has a substantially rectangular cross section (it is to be understood, that the cross section may also be hexagonal, or shaped differently). Due to the substantially rectangular cross section, the antenna element 110 has four contact faces 116a, 116b, 116c, 116d (cf. Figs. 3-5). The contact faces are configured to contact (directly or indirectly) a further antenna front end module 102, respectively an antenna element, thereof. Thus, a galvanic or capacitive coupling can be achieved.

[0079] Further, the antenna element 110 has a propagation face 117, which accommodates the open ended wave guide apertures 112a, 112b (or horn radiators).

[0080] The antenna element 110 may be a one-piece element, e.g. a metallic body or a metallized plastic body. Hence, the wave guide feed 114, the at least one radio-frequency waveguide 112 and the apertures 112a, 112b can be integrally formed.

[0081] The front end element 140 may include a carrier PCB 146, carrying electronic components 147, such as a TRx component. On a side opposite to the PCB 146, the electronic components 147 may be covered, e.g. by an electrically isolating cover 148. The TRx component may include active components such as a transmitting amplifier, a receiving amplifier and / or at least one switch for time-division-duplexing, TDD, operations.

[0082] The metallic body of the antenna element 110 may include a protrusion 134. The PCB may have a corresponding recess or opening, allowing the protrusion 134 to thermally contact the electronic components, which have a high heat generation, such as an TRx amplifier.

[0083] Further, the antenna element 110, particularly the metallic body, may operate as a heat sink for the dissipation power generated by the electronic components 147, mainly generated by the TRx amplifier 104. To improve the heat flow between the PCB 146 and the antenna element 110, metallic pins may be provided, that are fit in respective through holes of the PCB. Further, the PCB 146 may include vias to thermally couple to the antenna element 110. In case multiple antenna elements 110 are arranged in an array (cf. Fig. 6 and 7), heat can be dissipated over neighboring antenna elements 110. Further, the propagation face 117 including the apertures 112a, 112b may serve as cooling surface, that releases generated heat to the environment. Additional heat sink elements may be provided, which are thermally coupled to the antenna elements 110 of an active antenna array.

[0084] The PCB 146 may further include at least one conductive path 149 for connecting the front end element 140 to an ADC-DAC-module 50 (e.g. via a flex PCB being soldered or otherwise electrically connected to the conductive path 149. Further, the antenna element 110 has a first recessed portion 120, which is shaped and located so as to accommodate the front end element 140 at least partially (cf. assembled view of Fig. 4).

[0085] Further, as shown in Figs. 4 and 5, the antenna element 110 has a second recessed portion 130. The second recessed portion 130 is located opposite to the front end element 140 and configured to accommodate a front end element of a further antenna front end module 102 being in contact with the at least one contact face 116a. This can be best seen in Fig. 6.

[0086] As further shown in Fig. 4, the apertures 112a, 112b, of the 1x6 array are oriented so that they provide for a +45° polarization. For achieving a dual polarized radiation, a further front end module may include an antenna element having differently oriented apertures. For example, the apertures of the antenna element of the further front end module may be oriented so as to provide a -45° polarization.

[0087] As best seen in Fig. 5, the antenna element 110 may have a third recessed portion 132. The third recessed portion 132 is designed so as to prevent shorting a feeder pin 144 of an antenna front end module contacting the antenna front end module on contact face 116c.

[0088] Fig. 6 gives a schematic view of an active antenna array 10 according to the invention. The active antenna array 10 shown in Fig. 6 includes ten antenna front end modules 100, 102, which are arranged in an 2x5 array.

[0089] The antenna front end modules 100, 102 contact each other at respective contact faces, so that the propagation faces 117, 119 of the antenna front end modules 100; 102 are aligned in a common propagation plane A (cf. Fig. 7).

[0090] The contact between adjacent antenna front end modules may be direct thereby providing for a galvanic coupling. Alternatively, the contact may be an indirect contact, thereby providing for a capacitive coupling. The indirect contact may be achieved by providing a separating varnish or thin dielectric film.

[0091] Fig. 7 shows a schematic view of a further active antenna array 10 according to the invention. The active antenna array 10 shown in Fig. 7 includes 64 antenna front end modules 100, 102, which are arranged in an 8x8 array.

[0092] The front end modules 100, 102 are positioned so that the antenna elements contact each other at respective contact faces and that the propagation faces 117, 119 of the antenna front end modules 100; 102 are aligned in a common propagation plane A.

[0093] The common propagation plane A may form a monolithic reflector. This reflector may serve as a reflector for at least one low-band and / or midband radiator 30.

[0094] Further, the antenna may further comprise at least one ADC-DAC-module 50, the ADC-DAC module 50 may be connected to every front end module of the array 10 or to a sub-array only. For example, an individual ADC-DAC-module 50 may be provided for every row or column of the active antenna array.

[0095] Fig. 8 shows a schematic view of a V-shaped active antenna array 10 according to the invention. The array 10 includes 3 columns and 5 rows of front end modules 100, 102. Here, the front end modules 100, 102 are not arranged in a grid structure (as e.g. shown in Fig. 7) but the rows are arranged offset to each other, resulting in a V-shape. This prevents interferences. List of Reference Signs

[0096] 1 base station

[0097] 10 antenna array

[0098] 12 base station antenna

[0099] 20 ADC-DAC module

[0100] 30 low band radiator

[0101] 31 radio unit

[0102] 32 radio unit

[0103] 40 control unit

[0104] 50 ADC-DAC-module

[0105] 100 antenna front end module

[0106] 102 antenna front end module

[0107] 103 TDD switch

[0108] 104 amplifier

[0109] 105 calibration

[0110] 106 control (e.g. CFR, AD / DA, DPD, AGC, phase)

[0111] 107 power supply

[0112] 108 control and / or sync signal

[0113] 110 antenna element

[0114] 112 radio-frequency waveguide

[0115] 112a aperture

[0116] 112b aperture

[0117] 114 wave guide feed

[0118] 115 filter

[0119] 116a-d contact face

[0120] 117 propagation face

[0121] 119 propagation face

[0122] 120 first recessed portion

[0123] 130 second recessed portion

[0124] 132 third recessed portion

[0125] 134 protrusion

[0126] 140 front end element

[0127] 144 feeder pin

[0128] 146 PCB 147 electronic components (may include TDD switch, amplifier, calibration, control (e.g. CFR, AD / DA, DPD, AGC, phase), power supply, control and / or sync signal device, and / or the like) 148 cover

[0129] 200 signal

[0130] 210 data

[0131] A plane

Claims

Claims 1 to 201. An antenna front end module (100) for an active antenna array (10), the antenna front end module (100) comprising an antenna element (110) and a front end element (140), wherein the antenna element (110) includes at least one wave guide feed (114), at least one radio-frequency waveguide (112), and at least two apertures (112a, 112b), wherein the radio-frequency waveguide (112) includes a wave guide harness element that connects the wave guide feed (114) with the at least two apertures (112a, 112b), and wherein the apertures (112a, 112b) are open ended waveguide apertures of the at least one radio-frequency waveguide (112) or horn radiators; and wherein the front end element (140) is connected to the at least one wave guide feed (114) for receiving and / or transmitting radio-frequency signals (200).

2. The antenna front end module (100) according to claim 1, wherein the antenna element (110) includes an array of open ended waveguide apertures, wherein the array may include at least 2, or at least 4 or at least 6, or at least 8, or at least 20, or at least 80 open ended waveguide apertures.

3. The antenna front end module (100) according to claim 1 or 2, wherein the antenna element (110) has at least one contact face (116a, 116b, 116c, 116d) and a propagation face (117), wherein the at least one contact face (116a, 116b, 116c, 116d) is configured to contact a further antenna front end module (102), and wherein the propagation face (117) includes the at least two apertures (112a, 112b).

4. The antenna front end module (100) according to any one of claims 1 to 3, wherein the antenna element (100) includes a filter, particularly a high pass filter and / or a band pass filter and / or a dual-band filter, whereinthe filter is provided within the wave guide (112) or connected to the wave guide (112).

5. The antenna front end module (100) according to any one of claims 1 to 4, wherein the antenna front end module (100) is configured for receiving and / or transmitting radio-frequency signals being in a frequency range from 5 GHz to 100 GHz.

6. The antenna front end module (100) according to any one of claims 1 to 5, wherein the wave guide feed (114), the at least one radio-frequency waveguide (112), and the at least two apertures (112a, 112b) are integrally formed, and wherein the antenna element (110) is a one-piece metal element, or wherein the antenna element (110) is a one-piece element having a metallized surface.

7. The antenna front end module (100) according to any one of claims 1 to 6, wherein the antenna element (110) is formed by an additive manufacturing technique, injection molded or die casted.

8. The antenna front end module (100) according to any one of claims 1 to 7, wherein the antenna element (110) is made of, or metallized with at least one of the following materials: aluminum, magnesium, titan, zinc, copper, silver, gold, chromium, nickel, beryllium, and / or an alloy thereof.

9. The antenna front end module (100) according to any one of claims 3 to 8, wherein the at least one contact face (116a, 116b, 116c, 116d) is a heat transmission surface, configured for dissipating heat generated by the antenna front end module (100).

10. The antenna front end module (100) according to any one of claims 1 to 9, wherein the antenna element (110) includes at least one channel for guiding a heat transfer medium.

11. The antenna front end module (100) according to any one of claims 1 to 10, wherein the antenna element (110) has a first recessed portion (120), wherein the waveguide feed (114) is located in the first recessed portion (120), and wherein the first recessed portion (120) accommodates the front end element (140) at least partially.

12. The antenna front end module (100) according to any one of claims 1 to 11, wherein the antenna element (110) has a second recessed portion (130), the second recessed portion being located opposite to the front end element (140), wherein the second recessed portion (130) is configured to accommodate a front end element of a further antenna front end module (102) being in contact with the at least one contact face (116a), and wherein the antenna element (110) optionally has a third recessed portion (132), the third recessed portion being designed so as to prevent shorting a feeder pin (144) of the further antenna front end module (102).

13. An active antenna array (10), comprising at least two antenna front end modules (100; 102) according to any one of claims 1 to 12, the front end modules (100; 102) being arranged so as to form an antenna array.

14. The active antenna array (10) according to claim 13, wherein the antenna front end modules (100, 102) contact each other at respective contact faces (116a, 116b, 116c, 116d) so that the propagation faces (117; 119) of the at least two antenna front end modules (100; 102) are aligned in a common plane (A).

15. The active antenna array (10) according to claim 13 or 14, wherein the antenna front end modules (100, 102) are arranged in a V-shape, wherein the propagation faces (117; 119) of the antenna front end modules (100; 102) are aligned in a common plane (A).

16. The active antenna array (10) according to any one of claims 13 to 15, further comprising at least one ADC-DAC-module (50), the ADC-DAC module being electrically connected to at least two of the front end modules (100, 102).

17. The active antenna array (10) according to any one of claims 13 to16, further comprising at least one heat sink element, the heat sink element being thermally connected to at least one contact face of the front end modules (100, 102).

18. The active antenna array (10) according to any one of claims 13 to17, further comprising at least one low-band and / or mid-band radiator (30), wherein the at least one low-band and / or mid-band radiator (30) are arranged so that the common plane (A) forms a reflector for the at least one low-band and / or mid-band radiator (30).

19. The active antenna array (10) according to any one of claims 13 to 17, further comprising at least one amplifier module, the amplifier module being configured to amplify a received signal and / or a signal to be transmitted.

20. Base station (1) for mobile communications, the base station (1) including at least one active antenna array (10) according to any one of claims 13 to 19.

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