Calibration device, base station antenna and communication assembly

Abstract

The invention relates to a calibration device for an antenna, characterized in that the calibration device comprises a dielectric substrate and a metal pattern printed on the dielectric substrate, the metal pattern comprising at least a part of a calibration circuit, a first part of the calibration circuit being arranged on a first main surface of the dielectric substrate and a second part of the calibration circuit being arranged on a second main surface of the dielectric substrate opposite to the first main surface, the first part and / or the second part of the calibration circuit being configured as a coplanar waveguide transmission line. Thereby, a high interference immunity of the antenna system can be achieved at reasonable costs. Furthermore, the invention relates to a base station antenna and a communication assembly.

Description

TECHNICAL FIELD

[0001] The present application relates generally to radio communication, and more particularly to a calibration device, a base station antenna and a communication assembly. BACKGROUND

[0002] Cellular communication systems are well known in the art. In a cellular communication system, a geographical area is divided into a series of regions, which are referred to as "cells" served by various base stations. A base station can include one or more base station antennas configured to provide bi-directional radio frequency ("RF") communication with mobile subscribers within a cell served by the base station.

[0003] In many cases, each base station is divided into sectors. In the most common configuration, a hexagonal cell is divided into three 120° sectors, each of which is served by one or more base station antennas having a half-power beamwidth (HPBW) of approximately 65°. Typically, the base station antennas are mounted on a tower structure with the radiation pattern (also referred to herein as "antenna beam") produced by the base station antenna pointing outward. The base station antennas are typically implemented as linear or planar phased arrays of radiating elements.

[0004] Due to the ever-increasing demand for wireless communication, multi-band technology, multiple-input multiple-output technology and beamforming technology are rapidly developed in order to support different services and massive data transmission. However, as more and more frequency bands and / or radio frequency ports are integrated in one base station antenna, the antenna system, e.g. the feed network and / or the calibration network, becomes more complex and more susceptible to interference. Therefore, how to achieve high interference rejection performance of the antenna system at a reasonable cost is a technical problem to be solved by those skilled in the art. SUMMARY

[0005] Therefore, it is an object of the present application to provide a calibration device, a base station antenna and a communication assembly which can overcome at least one of the drawbacks in the prior art.

[0006] According to a first aspect of the present application, a calibration device for an antenna is provided. The calibration device comprises a dielectric substrate and a metal pattern printed on the dielectric substrate, the metal pattern comprising at least a part of a calibration circuit, a first part of the calibration circuit being arranged on a first main surface of the dielectric substrate and a second part of the calibration circuit being arranged on a second main surface of the dielectric substrate opposite to the first main surface, the first part and / or the second part of the calibration circuit being configured as a coplanar waveguide transmission line. The calibration device according to some embodiments of the present application can achieve high interference rejection performance of the antenna system at a reasonable cost.

[0007] In some embodiments, the first part of the calibration circuit comprises at least a radio frequency port and / or a coupler.

[0008] In some embodiments, the second part of the calibration circuit comprises at least the calibration port and / or the power combiner.

[0009] In some embodiments, the first part of the calibration circuit comprises a plurality of first conductive traces and the second part of the calibration circuit comprises a plurality of second conductive traces, and the metal pattern further comprises first coplanar ground regions printed on both sides of at least some of the first conductive traces and second coplanar ground regions printed on both sides of at least some of the second conductive traces.

[0010] In some embodiments, the first coplanar ground regions are spaced apart from the first conductive traces by a first slot within which the metalization is removed, and the second coplanar ground regions are spaced apart from the second conductive traces by a second slot within which the metalization is removed.

[0011] In some embodiments, with reference to a direction perpendicular to the first main surface of the dielectric substrate,

[0012] the first part of the calibration circuit is directly above at least a portion of the second coplanar ground regions, and / or

[0013] the second part of the calibration circuit is directly below at least a portion of the first coplanar ground regions.

[0014] In some embodiments, the first part of the calibration circuit and / or the second part of the calibration circuit are at least partially constituted by a coplanar waveguide transmission line with back metalization.

[0015] In some embodiments, the first slot and the second slot have a width comprised between 0.1 mm and 1 mm.

[0016] In some embodiments, the first part of the calibration circuit is electrically connected to the second part of the calibration circuit by means of a first conductive structure.

[0017] In some embodiments, the first conductive structure comprises a via or a metal conductor.

[0018] In some embodiments, the first coplanar ground regions are electrically connected to the second coplanar ground regions by means of a second conductive structure.

[0019] In some embodiments, the second conductive structure comprises a via or a metal conductor.

[0020] According to a second aspect of the present application, a base station antenna is provided. The base station antenna comprises a reflector, a calibration device and a substrate, wherein an antenna array is mounted on a front side of the reflector, and the substrate and the calibration device are mounted on a back side of the reflector, and the calibration device is mounted on the substrate, wherein the calibration device comprises a dielectric substrate and a metal pattern printed on the dielectric substrate, the metal pattern comprising at least a part of a calibration circuit, a first part of the calibration circuit being arranged on a first main surface of the dielectric substrate, and a second part of the calibration circuit being arranged on a second main surface of the dielectric substrate opposite to the first main surface, the first part of the calibration circuit comprising a radio frequency port and a coupler.

[0021] In some embodiments, the second part of the calibration circuit comprises a calibration port and / or a power combiner.

[0022] In some embodiments, the first part of the calibration circuit is electrically connected to the second part of the calibration circuit by means of a first electrically conductive structure.

[0023] In some embodiments, an output of the coupler of the first part of the calibration circuit is electrically connected to an input of the power combiner of the second part of the calibration circuit by means of the first electrically conductive structure.

[0024] In some embodiments, a slot is provided on the substrate, in which slot metal is removed, wherein the first part of the calibration circuit falls within the range of the slot, thereby avoiding direct electrical contact between the first part of the calibration circuit and the substrate.

[0025] In some embodiments, the first and second parts of the calibration circuit are configured as coplanar waveguide transmission lines.

[0026] In some embodiments, the first part of the calibration circuit comprises a plurality of first electrically conductive tracks, and the second part of the calibration circuit comprises a plurality of second electrically conductive tracks, and the metal pattern further comprises a first coplanar ground region printed on both sides of at least some of the first electrically conductive tracks and a second coplanar ground region printed on both sides of at least some of the second electrically conductive tracks.

[0027] In some embodiments, the first coplanar ground region is spaced apart from the first electrically conductive tracks by a first slot, in which slot metal is removed, and the second coplanar ground region is spaced apart from the second electrically conductive tracks by a second slot, in which slot metal is removed.

[0028] In some embodiments, the first part of the calibration circuit and / or the second part of the calibration circuit are at least partially configured as coplanar waveguide transmission lines with a back metallization.

[0029] In some embodiments, the first coplanar ground region is electrically connected to the second coplanar ground region by means of a second electrically conductive structure.

[0030] In some embodiments, the calibration device is configured as a single-layer printed circuit board, which comprises only one dielectric substrate between the first part of the calibration circuit and the second part of the calibration circuit.

[0031] According to a third aspect of the present application, a communication assembly is provided, comprising a radio frequency unit and a base station antenna according to embodiments of the present application, wherein the substrate is arranged at the front side of the calibration device and the radio frequency unit is arranged at the back side of the calibration device, such that the first main surface of the dielectric substrate of the calibration device is arranged facing away from the radio frequency unit.

[0032] In some embodiments, the radio frequency unit and the calibration device are bidirectionally transmitting RF signals by means of a coaxial connection.

[0033] In some embodiments, a filter is further arranged between the radio frequency unit and the calibration device. BRIEF DESCRIPTION OF DRAWINGS

[0034] The application is explained in more detail below with reference to specific embodiments. The accompanying drawings briefly described below illustrate the application schematically:

[0035] Figure 1 is a schematic top view of a communication assembly according to some embodiments of the present application, comprising a base station antenna according to some embodiments of the present application together with an integrated RRU;

[0036] Figure 2 is a schematic partial cross-sectional view of the calibration device of the base station antenna in Figure 1 according to some embodiments of the present application;

[0037] Figure 3 is a simplified schematic view of the first part of the calibration circuit on the calibration device in Figure 2

[0038] Figure 4 is a simplified schematic view of the second part of the calibration circuit on the calibration device in Figure 2

[0039] Figure 5 is a partial enlarged schematic view of the first part of the calibration circuit in Figure 3

[0040] Figure 6 is a partial schematic view of the second part of the calibration circuit in Figure 4 DETAILED DESCRIPTION

[0041] ​​​​The present application will now be described with reference to the attached figures. Various embodiments of the application are illustrated in the drawings and are described in detail below. It should be understood, however, that the application can be practiced in a variety of embodiments other than those novelty described below and illustrated in the drawings. In fact, the application encompasses a variety of embodiments, all of which are not specifically described below. Further, it should be understood that the embodiments disclosed herein and illustrated in the drawings are merely exemplary and should not be considered as limiting the scope of the application. It should also be understood that the embodiments disclosed herein can be combined in various ways without departing from the application.

[0042] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Methods and materials are described herein for use in the present application and in its practices.

[0043] In the present document, references to "one" or "the" element, embodiment, etc. do not necessarily mean the same element or the same embodiment; reference to "one" or "the" element or embodiment or the like means at least one.

[0044] In the present document, spatially relative terms, such as "beneath", "below", "lower", "above", "upper", "left", "right", "front", "back", "up", "down", "top", "bottom", "under", "over", "horizontal", "vertical", "above", "below", "clockwise", "counter clockwise", "side", etc., are used for ease of description to describe one element's or feature's relation to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device described is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors will be interpreted accordingly. Similarly, when a device is said to be "connected" to another device, it is not only directly connected to the other device, but can also be connected to the other device through one or more other devices.

[0045] As used herein, the term "or" is not meant to be exclusive and refers to at least one of either. For example, "A or B" or "A or B" means "A, B, or both A and B".

[0046] In this document, the terms "illustrative" or "exemplary" mean "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other implementations. Any implementation described herein as illustrative is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, the present application is not limited to any particular stated theory of operation.

[0047] In this document, the term "substantially" means including any minor variations as a result of design or manufacturing tolerances, device or element variations, environmental influences, and / or other factors.

[0048] In this document, the term "at least a portion" can be any fraction of a whole. For example, it can be greater than 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or even 100% or all.

[0049] In addition, for purpose of reference only, the terms "first", "second", and like terms can also be used herein and, therefore, are not intended to be limiting. For example, unless otherwise clear by context, the words "first", "second", and other such numerical terms referring to structures or elements do not imply an order or sequence unless specifically stated.

[0050] It is also to be understood that the term "comprising" or "including" when used in this document signifies the presence of the stated features, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0051] Some embodiments of the present application will now be described in greater detail below with reference to the drawings.

[0052] Reference will now be made to Figure 1 , Figure 1A schematic top view of a communication assembly according to some embodiments of the present application is shown, comprising a base station antenna 100 together with an integrated RRU. The base station antenna 100 can be mounted on a raised structure, such as an antenna tower, a utility pole, a building, a water tower, etc., so that its longitudinal axis extends approximately perpendicular to the ground for operation. The base station antenna 100 comprises a radome 110 providing environmental protection and comprises a reflector 120, which can comprise a metallic surface providing a ground plane and reflecting electromagnetic waves arriving thereat, e.g. redirecting them to propagate forward. The base station antenna 100 further comprises a feed panel 130 arranged at the front side of the reflector 120. In some embodiments, an antenna array 140 and its feed circuitry can be integrated on the feed panel 130. In other embodiments, a plurality of feed panels 130 can be provided and individual subsets of radiating elements of the antenna array 140 are mounted on individual feed panels 130. The base station antenna 100 further comprises mechanical and electronic components, such as connectors, cables, phase shifters, remote electronic tilt units, duplexers, calibration devices 200, filters 160, etc., which can be arranged at the back side of the reflector 120. Furthermore, a remote radio unit (RRU) 300 can be integrated outside the base station antenna 100, e.g. mounted at the back side of the base station antenna 100.

[0053] In some types of base station antennas 100, such as beamforming antennas, a calibration device 200 is typically required to compensate for phase and / or amplitude deviations of the radio frequency signals input at different radio frequency ports due to uncontrolled errors in the design, manufacture or use of the radio frequency control system, such as the remote radio unit 300 "RRU", or the antenna feed network. This process is commonly referred to as "calibration".

[0054] The calibration device 200 can be configured as a printed circuit board separate from the feed panel 130. Typically, the calibration device 200 needs to be mounted on a base plate 170 for structural strength considerations, which can be a plate of any suitable form, such as a metal plate. For performing the calibration, the calibration device 200 and the remote radio unit 300 can bi-directionally transmit RF signals by means of known coaxial connection means 180, which can be coaxial connectors or coaxial cables.

[0055] The calibration device can include a dielectric substrate, a microstrip calibration circuit provided on a first major surface of the dielectric substrate, and a ground metal layer provided on a second major surface of the dielectric substrate. However, as more and more frequency bands and / or radio frequency ports are integrated in the base station antenna, for example, from 8X8 MIMO (8R8T) to 64X64 MIMO (64R64T), the calibration device 200 becomes more and more sensitive to external interference signals, which can be noise signals from the surrounding environment or RF signals reflected back by metal components inside or near the base station antenna 100. Since the calibration device 200 is arranged adjacent to the remote radio unit 300, which has a metal housing 310, RF signals emitted from the calibration device 200 are easily reflected back into the calibration device 200 by the metal housing 310. The reflected signals can interfere with the calibration circuit 220 in the calibration device 200.

[0056] To improve the anti-interference performance of the calibration device itself, the calibration circuit of the conventional calibration device can be designed as a stripline network. To this end, the conventional calibration device can be configured as a multi-layer printed circuit board including at least two dielectric substrates, wherein a first ground metal layer can be provided on the upper surface of the upper dielectric substrate, and a second ground metal layer can be provided on the lower surface of the lower dielectric substrate, and the calibration circuit is provided in the metal layer between the two dielectric substrates, so that the calibration circuit is surrounded by the first and second ground metal layers, and thus the calibration circuit can be configured as a stripline network. The stripline network can be advantageous because they can have reduced radiated signal loss and can shield the radio frequency transmission lines from external radiation. However, the stripline network also has some limitations: first, it is complicated to manufacture the calibration circuit based on the stripline. Second, the cost is high. Third, it is difficult to debug the RF performance of the calibration circuit and other drawbacks. Therefore, how to realize high anti-interference performance of the antenna system at a reasonable cost is a technical problem that technicians in the field are eager to solve.

[0057] Next, with reference to Figures 2 to 6 The calibration device 200 according to some embodiments of the present application is described in detail. Figure 2 is a schematic partial cross-sectional view of the calibration device 200 according to some embodiments of the present application; Figure 3 is a simplified schematic diagram of a first part 220-1 of the calibration circuit 220 on the calibration device 200; Figure 4 is a simplified schematic diagram of a second part 220-2 of the calibration circuit 220 on the calibration device 200; Figure 5 is a partial enlarged schematic diagram of the first part 220-1 of the calibration circuit 220; Figure 6 is a partial schematic diagram of the second part 220-2 of the calibration circuit 220.

[0058] Referring toFigure 2 The calibration device 200 of some embodiments of the present application can be configured as one printed circuit board, e.g. a single-layer printed circuit board. For reasons of structural strength, the calibration device 200 can be mounted to a base plate 170, see Fig. 1 1. In some embodiments, the base plate 170 is advantageously arranged at the front side of the calibration device 200, so that the pressing forces caused by the remote radio unit 300 are not mainly taken up by the calibration device 200, but mainly by the base plate 170, thus ensuring the structural safety of the calibration device 200. Figure 1 In some embodiments, the base plate 170 is advantageously arranged at the back side of the calibration device 200, so that the pressing forces caused by the remote radio unit 300 are not mainly taken up by the calibration device 200, but mainly by the base plate 170, thus ensuring the structural safety of the calibration device 200. Figure 1 In some embodiments, the base plate 170 is advantageously arranged at the back side of the calibration device 200, so that the pressing forces caused by the remote radio unit 300 are not mainly taken up by the calibration device 200, but mainly by the base plate 170, thus ensuring the structural safety of the calibration device 200.

[0059] The calibration device 200 can comprise a dielectric substrate 210 and a metal pattern printed on the dielectric substrate 210. The metal pattern can comprise at least a part of a calibration circuit 220. In some embodiments, the calibration device 200 is configured as one printed circuit board only, and the printed circuit board can comprise the entire calibration circuit 220. In other embodiments, the calibration device 200 can comprise two or more printed circuit boards, each of which can comprise a part of the calibration circuit 220 and can be connected to each other by means of a conductive connection, e.g. a coaxial cable, a coaxial connector or a conductive body, etc.

[0060] The calibration circuit 220 can comprise a calibration port 230, a transmission path 240, a power combiner 250 and a coupler 260. The power combiner 250 can be configured as a Wilkinson power combiner, and the coupler 260 can be configured as a directional coupler. The calibration circuit 220 can be used to identify any undesired changes in the amplitude and / or phase of the RF signals input to the different RF ports 270 of the antenna 100.

[0061] According to some embodiments of the present application, the calibration circuit 220 can be divided into at least two parts, wherein a first part 220-1 of the calibration circuit 220 can be arranged on a first main surface 2101 of the dielectric substrate 210, and a second part 220-2 of the calibration circuit 220 can be arranged on a second main surface 2102 of the dielectric substrate 210 opposite to the first main surface 2101. The first main surface 2101 of the dielectric substrate 210 is arranged away from the remote radio unit 300, and the second main surface 2102 of the dielectric substrate 210 is arranged towards the remote radio unit 300. Thus, the first part 220-1 of the calibration circuit 220 is at least further away from the remote radio unit 300, so that the interference of the remote radio unit 300 to at least a part of the calibration circuit 220 is reduced. Furthermore, dividing the calibration circuit 220 into at least two parts can reduce the size of the calibration device 200, so that the compact structure of the base station antenna 100 is maintained.

[0062] To prevent the first part 220-1 of the calibration circuit 220 from shorting with the substrate 170, a region of the substrate 170 corresponding to the first part 220-1 of the calibration circuit 220 can be slotted (not shown), in which the metal is removed, thereby avoiding direct electrical contact between the first part 220-1 of the calibration circuit 220 and the substrate 170. Since only a part of the calibration circuit 220 (i.e. the first part 220-1) needs to be slotted, the slotted region of the substrate 170 is relatively limited, thereby ensuring a high level of structural strength of the substrate 170.

[0063] With reference to Figure 3 and 4 In some embodiments, the first part 220-1 of the calibration circuit 220 can comprise the radio frequency ports 270 and the couplers 260. The second part 220-2 of the calibration circuit 220 can comprise the calibration ports 230 and the power combiner 250. The output 280 of each coupler 260 can be electrically connected to the input 282 of the power combiner 250 by means of a first electrically conductive structure (not shown), e.g. a via or a metal conductor. The first part 220-1 of the calibration circuit 220 can be electrically connected to the second part 220-2 of the calibration circuit 220 by means of a second electrically conductive structure (not shown), e.g. a via or a metal conductor. Figure 3 and 4 The design scheme of the calibration circuit 220 is advantageous in that: first, the radio frequency ports 270 and the couplers 260 can be arranged away from the remote radio unit 300. Since the couplers 260 are relatively sensitive to radiated energy and near-field coupling, arranging the radio frequency ports 270 and the couplers 260 away from the side of the remote radio unit 300 can further reduce the interference of the remote radio unit 300 on the calibration circuit 220. Second, the first part 220-1 of the calibration circuit 220 only occupies a part of the entire calibration circuit 220, thereby the slotted region of the substrate 170 is relatively limited.

[0064] According to some embodiments of the present application, to further reduce the interference of external interference signals on the calibration circuit 220, the calibration circuit 220 can be configured as a coplanar waveguide transmission line. With reference to Figure 2 , 5In calibration circuit 220, coplanar ground regions (hereinafter referred to as first coplanar ground regions 290) are printed on both sides of the signal transmission lines of the first portion 220-1, and coplanar ground regions (hereinafter referred to as second coplanar ground regions 291) are printed on both sides of the signal transmission lines of the second portion 220-2. The first coplanar ground region 290 may be spaced apart from the first portion 220-1 by a first slot 292, in which metal is removed. The width W of the first slot 292 may be any suitable size, for example, between 0.1 mm and 1 mm or between 0.2 mm and 0.5 mm. The second coplanar ground region 291 may be spaced apart from the second portion 220-2 by a second slot 293, in which metal is removed. The second slot 293 may have the same or similar width as the first slot 292. In other words, the metal pattern on the dielectric substrate may include coplanar grounding regions surrounding the first portion 220-1 and the second portion 220-2 of the calibration circuit 220.

[0065] Coplanar waveguide transmission lines include coplanar waveguide transmission lines without backing metal and coplanar waveguide transmission lines with backing metal. Figure 2 In one embodiment, the calibration circuit 220 may be at least partially configured as a coplanar waveguide transmission line with a backing metal. (Refer to...) Figure 2 Referring to a direction perpendicular to the first main surface 2101 of the dielectric substrate 210 (indicated by arrow R), the first portion 220-1 of the calibration circuit 220 and at least a portion of the first coplanar ground region 290 can be positioned directly above at least a portion of the second coplanar ground region 291, and the second portion 220-2 of the calibration circuit 220 and at least a portion of the second coplanar ground region 291 can be positioned directly below at least a portion of the first coplanar ground region 290. The first coplanar ground region 290 can be electrically connected to the second coplanar ground region 291 via a second conductive structure 294, such as a via or a metal conductor. This coplanar waveguide transmission line with backing metal facilitates further shielding of the calibration circuit 220 from external signals, thereby improving the robustness and reliability of the calibration circuit 220.

[0066] In some implementations, the remote RF unit 300 may first input an RF signal to the corresponding RF port 270. Then, the calibration circuit 220 may extract a small portion of the corresponding RF signal from the RF port 270 via a coupler 260, and then combine the extracted signals into a calibration signal via a power combiner 250 and transmit it back to the remote RF unit 300. Thus, the remote RF unit 300 can adjust the amplitude and / or phase of the RF signal to be input to the RF port 270 according to the calibration signal to provide an optimized antenna 100 beam.

[0067] It should be understood that the calibration device 200 and the calibration circuit 220 can comprise other suitable configurations and / or modes of operation, and are not limited to the embodiments described above.

[0068] In other embodiments, the first part 220-1 of the calibration circuit 220 can comprise other RF devices, such as matching impedances or a power combiner 250, in addition to the RF ports 270 and the couplers 260. The second part 220-2 of the calibration circuit 220 can comprise matching impedances, etc., in addition to the calibration ports 230 and the power combiner 250.

[0069] In other embodiments, the calibration procedure can be reversed, in which case the power combiner 250 acts as a power divider. In this case, the remote radio unit 300 can first input the calibration signal to the calibration port 230. The calibration signal is then transmitted from the calibration port 230 via the respective transmission paths 240 to the power divider, which divides the calibration signal into a plurality of sub-components. The sub-components of the calibration signal are transmitted by the respective couplers 260 to the individual feed branches. The RF ports 270 can extract a small portion of the calibration signal by means of the couplers 260. The remote radio unit 300 can read the amplitude and / or phase of the RF signal coupled from the calibration circuit 220 via the couplers 260 to the RF ports 270. Thereby, the RRU can adjust the amplitude and / or phase of the RF signal to be input on the RF ports 270 accordingly to provide an optimized antenna 100 beam.

[0070] While the exemplary embodiments of the present application have been described above, it is understood that various modifications and changes can be devised by those skilled in the art which fall within the spirit and scope of the exemplary embodiments of the present application without departing from the spirit and scope of the exemplary embodiments of the present application, and that such modifications and changes are intended to fall within the scope of the exemplary embodiments of the present application.

Claims

1. A calibration apparatus for an antenna, characterized by, The calibration device comprises a dielectric substrate and a metal pattern printed on the dielectric substrate, the metal pattern comprising at least a part of a calibration circuit, a first part of the calibration circuit being arranged on a first main surface of the dielectric substrate and a second part of the calibration circuit being arranged on a second main surface of the dielectric substrate opposite to the first main surface, the first part and / or the second part of the calibration circuit being configured as a coplanar waveguide transmission line, wherein the first part of the calibration circuit comprises a plurality of first electrically conductive tracks and the second part of the calibration circuit comprises a plurality of second electrically conductive tracks, and the metal pattern further comprises a first coplanar ground region printed on both sides of at least some of the first electrically conductive tracks and a second coplanar ground region printed on both sides of at least some of the second electrically conductive tracks.

2. The calibration device of claim 1, wherein, The first part of the calibration circuit comprises at least a radio frequency port and / or a coupler.

3. The calibration device of claim 1, wherein, The second part of the calibration circuit comprises at least a calibration port and / or a power combiner.

4. The calibration device of claim 1, wherein, The first coplanar ground region is spaced apart from the first electrically conductive tracks by a first slot in which the metallization is removed and the second coplanar ground region is spaced apart from the second electrically conductive tracks by a second slot in which the metallization is removed.

5. The calibration device according to claim 1 or 4, characterized in that With reference to a direction perpendicular to the first main surface of the dielectric substrate, The first part of the calibration circuit is directly above at least a part of the second coplanar ground region and / or The second part of the calibration circuit is directly below at least a part of the first coplanar ground region.

6. The calibration device according to claim 1 or 4, characterized in that The first part of the calibration circuit and / or the second part of the calibration circuit are at least partially configured as a coplanar waveguide transmission line with back metallization.

7. The calibration device of claim 4, wherein, The width of the first slot and the second slot is between 0.1 mm and 1 mm.

8. The calibration device of claim 1, wherein, The first part of the calibration circuit is electrically connected to the second part of the calibration circuit by means of a first electrically conductive structure.

9. The calibration device of claim 8, wherein, The first electrically conductive structure comprises a via or a metal conductor.

10. The calibration device of claim 1, wherein, The first coplanar ground region is electrically connected to the second coplanar ground region by means of a second electrically conductive structure.

11. The calibration device of claim 10, wherein, The second electrically conductive structure comprises a via or a metal conductor.

12. A base station antenna, comprising: The base station antenna comprises a reflector, a calibration device and a substrate, an antenna array being mounted on a front side of the reflector and the substrate and the calibration device being mounted on a back side of the reflector, and the calibration device being mounted on the substrate, wherein the calibration device comprises a dielectric substrate and a metal pattern printed on the dielectric substrate, the metal pattern comprising at least a part of a calibration circuit, a first part of the calibration circuit being arranged on a first main surface of the dielectric substrate and a second part of the calibration circuit being arranged on a second main surface of the dielectric substrate opposite to the first main surface, the first part of the calibration circuit comprising a radio frequency port and a coupler and the second part of the calibration circuit comprising a calibration port and a power combiner.

13. The base station antenna of Claim 12, wherein, The first part of the calibration circuit is electrically connected to the second part of the calibration circuit by means of a first electrically conductive structure.

14. The base station antenna of Claim 13, further characterized by, An output of the coupler of the first part of the calibration circuit is electrically connected to an input of the power combiner of the second part of the calibration circuit by means of the first electrically conductive structure.

15. The base station antenna of Claim 12, wherein, A groove is provided on the substrate, in which groove the metal is removed, wherein the first part of the calibration circuit falls within the scope of the groove, so that direct electrical contact between the first part of the calibration circuit and the substrate is avoided.

16. The base station antenna of Claim 12, further characterized by, The first part and the second part of the calibration circuit are configured as coplanar waveguide transmission lines.

17. The base station antenna of Claim 16, wherein, The first part of the calibration circuit comprises a plurality of first electrically conductive tracks and the second part of the calibration circuit comprises a plurality of second electrically conductive tracks, and the metal pattern further comprises first coplanar ground regions printed on both sides of at least some of the first electrically conductive tracks and second coplanar ground regions printed on both sides of at least some of the second electrically conductive tracks.

18. The base station antenna of Claim 17, wherein, The first coplanar ground regions are spaced apart from the first electrically conductive tracks by first slots, in which slots the applied metal is removed, and the second coplanar ground regions are spaced apart from the second electrically conductive tracks by second slots, in which slots the applied metal is removed.

19. The base station antenna of one of claims 16 to 18, characterized in that, The first part of the calibration circuit and / or the second part of the calibration circuit are at least partially configured as coplanar waveguide transmission lines with back applied metal.

20. The base station antenna of Claim 17, wherein, The first coplanar ground regions are electrically connected to the second coplanar ground regions by means of a second electrically conductive structure.

21. The base station antenna of Claim 12, further characterized by, The calibration device is configured as a single-layer printed circuit board, which comprises only one dielectric substrate between the first part of the calibration circuit and the second part of the calibration circuit.

22. A communication assembly comprising a radio frequency unit and a base station antenna according to one of claims 12 to 21, wherein, The substrate is arranged on the front side of the calibration device, while the radio frequency unit is arranged on the rear side of the calibration device, so that the first main surface of the dielectric substrate of the calibration device faces away from the radio frequency unit.

23. The communication assembly of claim 22, wherein, The radio frequency unit and the calibration device transmit RF signals bi-directionally by means of a coaxial connection device.

24. The communication component of claim 23, wherein, A filter is also mounted between the radio frequency unit and the calibration device.

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