Antenna and mobile communication base station

Abstract

An antenna (14) has radiators (16), a phase shifter assembly (18), a signal conductor (22), a ground conductor (24) and a substrate (20). The phase shifter assembly (18) comprises a delay section (36) on a first surface (26) of the substrate (20), a shifting device (32) and a cover (34). The cover (34) covers the delay section (36), wherein the cover (34) is electrically connected to the ground conductor (24). An exclusion area (60) of the second surface (28) is at least 75% free of the ground conductor (24), wherein the exclusion area (60) includes an area (A1) of the second surface (28) corresponding to a vertical projection of the delay section (36) onto the second surface (28).Further, a mobile communication base station (10) is provided.

Description

[0001] Antenna and mobile communication base station

[0002] Technical Field The invention relates to an antenna and a mobile communication base station.

[0003] Background

[0004] Antenna arrays for mobile communication make use of phase shifters to tilt the beam. Some radiofrequency applications need analog phase shifters having a shifting device that needs to be shifted mechanically in order to create the necessary phase shift for tilting the beam.

[0005] Further, the phase shifters have to be arranged close to the radiators so that linear phase shifters on substrates have been developed to simplify the arrangement of the phase shifter assemblies between columns of radiators.

[0006] Such phase shifter assemblies are known, for example, from EP 4 044 359 Al. The known solutions, however, require much space on the surface of the substrate of the phase shifter assembly or multiple stacked layers to accommodate for the actual phase shifting components and the actuation of these components. Summary

[0007] It is therefore an object of the invention to provide an antenna with a phase shifter assembly, the phase shifter assembly requiring less space on a surface of a substrate without deterioration of signal quality.

[0008] For this purpose, an antenna, in particular for a mobile communication base station is provided. The antenna comprises radiators, at least one phase shifter assembly for radio frequency signals, in particular mobile communication signals, at least one signal conductor, a ground conductor and a substrate with a first surface and a second surface, wherein the radiators are attached to the first surface or the second surface of the substrate. The at least one phase shifter assembly comprises a delay section, a shifting device and a cover, wherein the delay section is a section of the at least one signal conductor located on the first surface of the substrate between the substrate and the cover. The shifting device comprises a shifting portion, the shifting portion comprising a dielectric material, being located on a first side of the substrate and covering the delay section at least partly, wherein the shifting device is movable with respect to the substrate in a direction of motion parallel to the first surface. The cover covers the delay section at least in the vertical direction, wherein the cover is electrically connected to the ground conductor. An exclusion area of the second surface is at least 75% free of the ground conductor, wherein the exclusion area includes an area of the second surface corresponding to a vertical projection of the delay section onto the second surface.

[0009] The inventors have realized that an exclusion area being at least 75% free of the ground conductor on the second surface opposite to the delay section increases the electromagnetic field in the area between the cover and the delay section. Thus, the presence of a dielectric in this region leads to higher phase shifts than in known phase shifters. At the same time, the overall signal quality does not deteriorate. Thus, a larger phase shift with the same mechanical length may be achieved or, put differently, to achieve a needed phase shift, the mechanical length may be reduced. Thus, it is possible to reduce the overall size and thus the space required by the phase shifter assembly on the substrate.

[0010] The cover is in particular fixed to the substrate. For example, the cover is galvanically connected to ground conductor.

[0011] In particular, each phase shifter assembly comprises a delay section.

[0012] The delay section is in particular fully covered by the cover.

[0013] The projection of the delay section is to be understood as the projection of the entire delay section. The same holds true for other projections mentioned in this disclosure.

[0014] For example, the exclusion area consists of an area of the second surface corresponding to a vertical projection of the delay section onto the second surface.

[0015] The term "surface" also includes, besides the actual surface of the substrate, the surface of a layer applied to the substrate, e.g. a solder mask, a metallization or the like.

[0016] In particular, the first side and the second side of the substrate correspond to the side of the substrate having the first surface or the second surface, respectively.

[0017] The ground conductor is in particular grounded, forming the RF-ground for the RF-signals carried by transmission lines of the substrate with the exception of the delay section. The ground conductor may be located partly on first surface and partly on second surface, or entirely on the first surface, or entirely on the second surface. For example, the radiators are dual-polarized radiators.

[0018] In an aspect, the exclusion area of the second surface is at least 90%, in particular 100% free of the ground conductor, and / or at least 75%, in particular at least 90%, more particularly 100% free of a grounded conductor, further improving the performance of the phase shifter assembly.

[0019] A grounded conductor is to be understood as any conductor electrically coupled, in particular galvanically coupled to ground.

[0020] In an embodiment, the at least one phase shifter assembly comprises a longitudinal direction and a transverse direction, wherein the exclusion area has a width in the transverse direction corresponding to the width of the delay section, corresponding to the width of the delay section plus 10%, in particular plus 20%, corresponding to the width of the shifting device, and / or corresponding to the width of the base. This way, the amount of phase shift may be tuned precisely.

[0021] In an aspect, the at least one phase shifter assembly comprises a longitudinal direction and a transverse direction, wherein the exclusion area has a length in the longitudinal direction corresponding to the length of a vertical projection of the delay section onto the second surface, corresponding to the length of the vertical projection of the delay section onto the second surface plus 2%, in particular plus 5%, and / or corresponding to the length of a vertical projection of the cover. This way, the amount of phase shift may be tuned precisely.

[0022] For example, the longitudinal direction corresponds to the direction of motion.

[0023] For low losses, the at least one signal conductor may comprise feeding sections galvanically connected to the delay section, wherein the ground conductor forms a ground plane for the feeding sections. The feeding sections are in particular distinct from the delay section and / or not covered by the cover.

[0024] The feeding sections may be coupled to the corresponding one of the radiators or to a subarray of the radiators and / or to a port of the antenna. The feeding section may be part of a feeding network of the antenna.

[0025] The feeding section may be located on the same and / or the other side of the substrate than the delay section.

[0026] In an aspect, the delay section is galvanically coupled to one of the radiators by one of the feeding sections, allowing for simple integration of the phase shifter assembly.

[0027] In an embodiment, the substrate comprises at least one connecting via, and at least one of the feeding sections galvanically coupled to the delay section extends on the second surface and is connected to the delay section by one of the at least one connecting via, in particular both of the feeding sections galvanically coupled to the delay section extend on the second surface and are connected to the delay section by one of the at least one connecting via each, allowing to place the delay section and the feeding section on different surfaces of the substrate.

[0028] For providing a shielded transmission line along the delay section, the cover may have a base, wherein the delay section and the shifting portion of the shifting device are located between the base of the cover and the first surface of the substrate; and / or in that the cover comprises sidewalls, wherein the sidewalls extend perpendicular to the first surface of the substrate.

[0029] In particular, the base extends parallel to the first surface of the substrate. The base, the sidewalls and the first surface may define a volume, wherein the delay section and the shifting portion of the shifting device are located in the volume.

[0030] In an aspect, the cover is atached to the first surface of the substrate, in particular by ataching, for example soldering, the cover to the ground conductor on the first surface of the substrate, allowing a direct connection between the ground conductor and the cover.

[0031] In an embodiment, the exclusion area includes an area of the second surface corresponding to a vertical projection of the cover, in particular the base of the cover, onto the second surface. By this measure, the electromagnetic field is further concentrated between the delay section and the cover.

[0032] In order to allow more flexibility in designing the antenna, the substrate may comprise a plurality of mounting vias, and the cover, in particular sidewalls of the cover, may comprise fixation legs extending through the mounting vias, wherein the exclusion area ends spaced apart from the mounting via.

[0033] The mounting vias may include conductive pads around their barrel in the substrate.

[0034] In particular, the exclusion area ends spaced apart from mounting via even if the area of any mentioned relevant vertical projection would include the mounting via.

[0035] In order to allow the cover to be atached from the second side, the cover may be atached to the substrate by ataching the fixation legs to the second surface of the substrate, in particular ataching the fixation legs to the respective mounting via and / or the ground conductor on the second surface of the substrate.

[0036] The atachment may be realized by soldering. In the case that the radiators are attached also on the second surface, the manufacture is simplified as soldering has to be performed on the second surface only.

[0037] For adjusting the phase shift provided by the phase shift assembly, the phase shifter assembly may comprise an actuating mechanism, wherein the actuating mechanism is mechanically connected to an actuation portion of the shifting device and designed such that it is able to move the shifting device in the direction of motion.

[0038] The actuating mechanism may comprise an actuator, in particular an electric motor, and a driving structure movable linearly in the direction of motion by the actuator, wherein the driving structure is attached to the actuation portion of the shifting device.

[0039] In an aspect, the shifting portion comprises cutouts; and / or the cover is made of a conductive material or provided with a conductive layer or coating, providing improved performance of the phase shifter assembly.

[0040] The delay section may run in a straight line or may run in meanders.

[0041] In an embodiment, the ground conductor forms a reflector for the radiators, covers an area of the first and / or second surface corresponding to a vertical projection of the radiators onto the respective surface, and / or surrounds the delay section fully on the first surface, further reducing the size of the antenna and improving performance.

[0042] In particular, the area of the second surface corresponding to a vertical projection of the radiators onto the second surface does not overlap with the exclusion area, or, in cases there is an overlap, no ground conductor is present in the area of overlap. In order to reduce the costs and size further, the substrate may be a doublesided substrate, e.g. having exactly two surfaces, may be a PCB, in particular of FR-2 or FR-4, and / or may have a thickness smaller than 1 mm, in particular smaller than 0.8 mm. The substrate may be chosen that small, as the exclusion area reduces the amount of electromagnetic field in the substrate even in thin substrates, while still enabling the required phase shift, as the electrical field is concentrated in the space between the delay section and the cover.

[0043] In an embodiment, the antenna comprises a plurality of phase shifter assemblies, wherein the radiators are arranged in columns parallel to the direction of motion, in particular wherein the phase shifter assemblies are located between the radiators of adjacent columns, providing a versatile antenna array.

[0044] For above mentioned purpose a mobile communication base station is further provided. The base station has at least one antenna as described above.

[0045] The features and advantages described with respect to the antenna also apply to the base station and vice versa.

[0046] Brief Description of the Drawings

[0047] Further features and advantages will be apparent from the following description as well as the accompanying drawings, to which reference is made. In the drawings:

[0048] Figure 1 shows a mobile communication base station according to an embodiment of the invention with an antenna according to an embodiment of the invention,

[0049] Figure 2 shows an exploded view of an array of the antenna of Figure 1,

[0050] Figure 3 shows an exploded view of a phase shifter assembly of the array of Figure 2, Figure 4 shows a perspective botom view of the phase shifter assembly of Figure 3,

[0051] Figures 5, 6 show a sectional view along the longitudinal and transverse direction, respectively, of the phase shifter assembly of Figure 3,

[0052] Figure 7 shows a sectional view along the transverse direction of the array of Figure 2,

[0053] Figure 8 shows an illustration of the exclusion area, and

[0054] Figure 9 shows a sectional view along the transverse direction of a phase shifter assembly of an antenna according to a second embodiment of the invention.

[0055] Detailed Description

[0056] Figure 1 shows an embodiment of a mobile communication base station 10.

[0057] The mobile communication base station 10 has a plurality of antennas 14 for providing speech and data connections to user devices. Mobile communication base stations 10 are also referred to as mobile communication cell sites.

[0058] The mobile communication base station 10 may be an access network node of a radio access network of a telecommunication network, or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points.

[0059] Moreover, as will be appreciated by those of skilled in the art, an access a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. The antenna 14 of the mobile communication base station 10 is, in the shown simplified example, a dual polarized antenna to provide speech and data connections in various frequency bands and can serve single or multiple bands in a multiband option.

[0060] The antenna 14 may also be a multiband antenna, which then comprises further radiators for different frequency bands.

[0061] Figure 2 shows exemplarily a column of the antenna 14 of the mobile communication base station 10 in an exploded view.

[0062] The antenna comprises a plurality of radiators 16, a plurality of phase shifter assemblies 18, a substrate 20, a signal conductor 22 and a ground conductor 24 (cf. Fig. 3).

[0063] In the shown embodiment, the radiators 16 are arranged in columns, wherein Figure 2 shows only a single column. Each column may constitute an antenna array with six radiators 16.

[0064] The radiators 16 are dual polarized radiators and designed to receive and transmit electromagnetic radiation in the radio frequency band, in particular in a frequency band between 0.5 GHz and 7 GHz.

[0065] The substrate 20 has a first surface 26 and a second surface 28 opposite to the first surface 26. The first side is thus the side of the first surface 26 and the second side is the side of the second surface 28.

[0066] The term "surface" also includes, besides the actual surface of the substrate, the surface of a layer applied to the substrate, e.g. a solder mask, a metallization or the like.

[0067] The substrate 20 is in particular a double-sided substrate and not a multilayered substrate, i.e. it has only two surfaces. It is made of FR-2 or FR-4 and has a thickness smaller than 1 mm, in particular smaller than 8 mm. The thickness may be 0.762 mm.

[0068] The signal conductor 22 and the ground conductor 24 are metallizations applied to the substrate 20. In the shown embodiment, the signal conductor 22 and the ground conductor 24 may be located entirely on the first surface 26, entirely on the second surface 28 or in parts on both surfaces 26, 28 of the substrate 20.

[0069] Both surfaces 26, 28 of the substrate 20 and, for example, the signal conductor 22 and the ground conductor 24, may be covered by solder mask 29.

[0070] A reflector plate 30, e.g. a metal sheet, may be provided on the second side of the substrate 20 spaced apart from the substrate 20, in particular spanning across several or all columns of radiators 16.

[0071] The substrate 20 also serves as a substrates of the plurality of phase shifter assemblies 18.

[0072] The antenna 14 and also the phase shifter assemblies 18 have a vertical direction V, being the direction perpendicular to the surfaces 26, 28 of the substrate 20. Further, the substrate 20 and thus the phase shifter assembly 18 have a longitudinal direction L and a transverse direction T, which are perpendicular to one another and extend parallel to the surfaces 26, 28.

[0073] For the shown column, four phase shifter assemblies 18 are provided located transversely of the radiators 16. In particular, in a vertical projection, the radiators and the phase shifter assemblies 18 (in particular their delay section) do not overlap with one another. The phase shifter assemblies 18 are located between the radiators 16 of adjacent columns.

[0074] Figures 3 and 4 show one of the phase shifter assemblies 18 in an exploded view and a perspective bottom view, respectively. Figures 5 and 6 show the phase shifter assembly 18 in a sectional view along the longitudinal direction L and the transverse direction T, respectively.

[0075] The one phase shifter assembly 18 is discussed in detail in the following, the other phase shifter assemblies are built in the same way.

[0076] The phase shifter assembly 18 may be configured to be used for radio frequency signals, for example having frequencies between 0.5 GHz and 7 GHz.

[0077] The phase shifter assembly 18 makes use of the substrate 20 and comprises a shifting device 32, a cover 34 as well as a delay section 36.

[0078] The delay section 36 is a section of the signal conductor 22. The delay section 36 is located entirely on the first surface 26, for example.

[0079] In the shown embodiment, the delay section 36 is straight having a main extension in the longitudinal direction L. It is conceivable that the delay section 36 may comprise meanders.

[0080] The shifting device 32 comprises a shifting portion 38 and an actuation portion 40.

[0081] The actuation portion 40 is, for example, a pin extending vertically rearwards (i.e. away from the radiators 16) from the shifting portion 38.

[0082] The shifting portion 38, and for example the entire shifting device 32, is located at the first side of the substrate 20.

[0083] The shifting portion 38 is made of a dielectric material and it is conceivable that the shifting portion 38 and the actuation portion 40 are made integrally of a single piece of dielectric material. The dielectric constant or relative permittivity of the dielectric material is above 5.5, in particular above 6.0. It may be 6.5. The shifting portion 38 extends in the longitudinal direction L and it extends above the delay section 36.

[0084] Seen onto the first surface 26, the shifting portion 38 thus covers at least parts of the delay section 36.

[0085] Further, the shifting portion 38 may comprise cutouts (see Fig. 3), for example so-called transformation windows.

[0086] The cover 34 is mainly located on the first side of the substrate 20 and fixed to the substrate 20.

[0087] In the shown embodiment, the cover 34 extends in the longitudinal direction L with a substantially constant cross-section, in particular except for fixation legs.

[0088] As best seen in Figure 6, in the transverse direction T, the cover 34 has a base 41 and two sidewalls 42.

[0089] The cover 34 is made of a conductive material, e.g. metal, or provided with a conductive layer or coating.

[0090] The base 41 extends in particular parallel to the first surface 26 and is located transversally between the sidewalls 42, wherein the sidewalls 42 extend from the transverse edges of the base 41 towards the substrate 20, in particular perpendicularly. For example, the cover 34 has a U-shaped cross-section.

[0091] The width of the base 41 in the transverse direction T corresponds to the width of the shifting portion 38 in the transverse direction T.

[0092] In the shown embodiment, the sidewalls 42 comprise fixation legs 44 at their edges facing away from the base 41. The substrate 20 comprises corresponding mounting vias 46. The mounting vias 46 comprise a barrel extending fully through the substrate 20 and conductive pads 47 on the first surface 26 and the second surface 28.

[0093] The mounting vias 46 correspond to the fixation legs 44 in terms of location and / or size. The fixation legs 44 of the sidewalls 42 are inserted in the barrels of the mounting vias 46 and fixed on the second surface 28 of the substrate 20. For example, the fixation legs 44 are fixed, e.g. by soldering, to the pad 47 on the second surface 28, providing an electric connection between the mounting via 46 and the cover 34.

[0094] In the assembled state, the cover 34, more precisely the base 41, is located vertically above the delay sections 36, thus covering the delay section 36 in the vertical direction V.

[0095] Also in the longitudinal direction L and the transverse direction T, the cover 34 covers the delay section 36 fully.

[0096] The shifting device 32 and in particular the shifting portion 38 are located between the cover 34 and the substrate 20, more precisely the base 41 of the cover 34 and the substrate 20.

[0097] The base 41, the sidewalls 42 and the first surface 26 define a volume, wherein the delay section 36 and the shifting portion 38 of the shifting device 32 are located in the volume.

[0098] The shifting device 32 is movable in a direction of motion M coinciding with the longitudinal direction L. The direction of motion M is also parallel to the first surface 26.

[0099] The columns of radiators 16 are also parallel to the direction of motion M. The shifting device 32 is driven via the actuation portion 40 as illustrated in Figure 5. Figure 5 includes schematically an actuating mechanism 48 of the phase shifter assembly 18 indicated in dashed lines.

[0100] The actuating mechanism 48 comprises an actuator 50, a gearing 52 and a driving structure 54.

[0101] In the shown embodiment, the driving structure 54 may be plate-shaped and thus be a driving plate.

[0102] The driving structure 54 extends parallel to a surface of the substrate 20 (in the shown embodiment the first surface 26), and the actuation portion 40 is attached to the driving structure 54 at its rear end, for example by screws.

[0103] The actuator 50 may be an electric motor and it is mechanically connected to the driving structure 54 by the gearing 52 in a way that the actuator 50 is able to move the driving structure 54 linearly in the direction of motion M.

[0104] Thus, by means of the actuator 50 and the driving structure 54, the actuation portion 40 and thus the entire shifting device 32 is actuated back-and-forth in the direction of motion M.

[0105] For feeding signals to and from the radiators 16, the signal conductor 22 is used.

[0106] The signal conductor 22 comprises, besides the delay section 36 of each of the phase shifter assemblies 18, feeding sections 56.

[0107] The feeding sections 56 may be located entirely on the first surface 26, entirely on the second surface 28 and partly on the first surface 26 and partly on the second surface 28.

[0108] In the shown embodiment, e.g. in Figure 5, the feeding sections 56 are located on the second surface 28. The feeding sections 56 and the delay sections 36 are distinct sections of the signal conductor 22, i.e. any given section of the signal conductor 22 may not be a delay section 36 and a feeding section 56 at the same time.

[0109] The feeding sections 56 are galvanically connected to the delay sections 36, wherein at each end of the delay section 36 in the longitudinal direction L, one of the feeding sections 56 is connected to it.

[0110] By virtue of one of the feeding sections 56, a galvanic connection between the delay section 36 and the respective radiator 16 (more precisely one of the polarization structures of the respective radiator 16) and / or a respective subarray of the radiators 16 is provided.

[0111] Another feeding section 56 provides a galvanic connection between the other end of the delay section 36 and a respective port 57 of the antenna 14.

[0112] The feeding sections 56 and the delay section 36 form a part of a feeding network of the antenna 14.

[0113] As best seen in Figure 5, the feeding sections 56 are coupled to the delay sections 36 be means of connecting vias 58 of the substrate 20. The connecting vias 58 are located at the ends of the delay section 36 in the longitudinal direction L, and extend from the first surface 26 of the substrate 20 to the second surface 28 of the substrate 20.

[0114] For the feeding sections 56 on the second surface 28, the ground conductor 24 serves as the ground plane, thus creating microstrip type lines.

[0115] To this end, in a vertical projection, the feeding sections 56 overlap with the ground conductor 24, except in regions of the connecting vias 58.

[0116] The feeding sections 56 and the ground conductor 24 thus form a transmission line for radio frequency signals as known in the art. The feeding sections 56 are not covered by the cover 34.

[0117] As seen in Figure 7, in the shown embodiment, the radiators 16 are located on the second side of the substrate, i.e. the side opposite to the delay section 36 and the shifting device 32, and attached to the second surface 28.

[0118] At least 80%, in particular 95% of the area of a vertical projection of the radiators 16 to the first surface 26 or second surface 28 are covered by the ground conductor 24. In cases where the exclusion area 60 and the vertical projection of the radiators 16 overlap, no ground conductor 24 is provided.

[0119] The radiators 16 are attached to the second surface 28, for example by soldering. The feeding sections 56 on the second surface 28 are then galvanically connected to the respective conductors of the radiators 16.

[0120] It is also conceivable that the radiators 16 are attached on the first side, i.e. attached to the first surface 26 of the substrate 20.

[0121] Further, the ground conductor 24 is galvanically connected to the mounting vias 46, in particular to the conductive pads 47 of the mounting vias 46 on the first surface 26. The conductive pads 47 are therefore grounded. Thus, as the cover 34 is galvanically connected to the mounting vias 46 on the second surface 28, the cover 34 is galvanically coupled to the ground conductor 24 and thus also grounded.

[0122] The ground conductor 24 on the first surface 26 may surround the delay section 36 fully. For example, the ground conductor 24 and the delay section 36 are of the same metallization on the first surface 26 separated by an area without metallization defining the contour of the delay section 36.

[0123] On the other hand, the delay section 36 is not provided with a ground conductor 24 or any other grounded conductor on the second surface opposite to it. On the second surface 28 in the region of the delay section 36 an exclusion area 60 is provided, as indicated in Figure 8.

[0124] The exclusion area 60 includes or consists of the area Al of the second surface 28 corresponding to a vertical projection of the delay section 36 onto the second surface 28. In other words, the area Al on the second surface 28 directly corresponding to the area of the delay section 36 on the first surface 26 is part of the exclusion area 60.

[0125] The exclusion area 60 may also include or consist of an area A2 of the second surface 28 which corresponds to a vertical projection of the base 41 of the cover 34, in particular the entire cover 34, to the second surface 28.

[0126] The area A2 and thus the exclusion area 60 ends at a distance from the pads 47 of the mounting vias 46. This is also the case even if a vertical projection of the cover 34 or the base 41 or the delay section 36 would include the area occupied by the mounting vias 46.

[0127] The exclusion area 60 may have a width wain the transverse direction T corresponding to the width wi of the delay section 36 or a width wacorresponding to the width wi of the delay section 36 plus 10% of the width wi of the delay section 36, in particular plus 20% of the width wi of the delay section 36. The width waof the exclusion area 60 may also correspond to the width W2 of the shifting device 32 or of the base 41.

[0128] In the longitudinal direction L, the exclusion area 60 may have a length lain the longitudinal direction L corresponding to the length h of the delay section 36 or corresponding to the length h of the delay section 36 plus 2% of the length h of the delay section 36, in particular plus 5% of the length h of the delay section 36. The length lamay also correspond to the length h of the base 41. The exclusion area 60 is at least 75%, in particular at least 90%, in particular 100% free of the ground conductor 24 or any other grounded conductor.

[0129] A grounded conductor is to be understood with in this disclosure as any conductor electrically, in particular galvanically coupled to ground. At least 75%, in particular at least 90%, in particular 100% of the area of the exclusion area 60 is not covered by the ground conductor 24 or any grounded conductor. Thus, as best seen in Figure 7, in the vertical direction V the delay section 36 has no conductive counterpart, e.g. ground plane, on the second surface 28. No microstrip type line is formed through the substrate 20 as, for example, is the case with the feeding sections 56. However, as the cover 34 is grounded, the cover 34 may serve as a ground plane so that a transmission line for radio frequency signals is provided.

[0130] This has the effect that the electromagnetic field of the RF signals propagating through the delay section 36 is located predominately, in particular to more than 80%, in the volume between the cover 34, in particular the base 41, and the delay section 36, and not in the substrate 20.

[0131] The shifting portion 38 of the shifting device 32 is located and moved exactly in this volume with the predominant portion of the electromagnetic field, so that the retarding effect of the shifting portion 38 on the RF signals is drastically increased. This way, the delay section 36 and thus the entire phase shifter assembly 18 can be reduced in size.

[0132] Further, in this embodiment, the fixation legs 44 extending through the substrate 20 also have a shielding effect on the delay section 36, reducing interference with the electromagnetic radiation of the radiator 16.

[0133] Thus, a very compact phase shifter assembly 18 is provided with a very large phase shift with respect to the space occupied on the substrate. Figure 9 shows a cross-section of a phase shifter assembly 18 of a second embodiment of the antenna 14 that corresponds substantially to the first embodiment. Thus, in the following, only the differences are discussed and the same and functionally the same components are labeled with the same reference signs.

[0134] In the second embodiment, the cover 34 is designed differently. The cover 34 does not have the fixation legs but the sidewalls 42 are attached to the first surface 26 of the substrate 20. For example, the sidewalls 42 are attached, in particularly soldered, to the ground conductor 24 on the first surface 26. Thus, also in the second embodiment, a galvanic connection between the cover 34 and the ground conductor 24 is provided.

[0135] Further, the substrate 20 does not need to have mounting vias, reducing complexity.

Claims

Claims1. Antenna, in particular for a mobile communication base station (10), comprising radiators (16), at least one phase shifter assembly (18) for radio frequency signals, in particular mobile communication signals, at least one signal conductor (22), a ground conductor (24) and a substrate (20) with a first surface (26) and a second surface (28), wherein the radiators (16) are attached to the first surface (26) or the second surface (28) of the substrate (20), wherein the at least one phase shifter assembly (18) comprises a delay section (36), a shifting device (32) and a cover (34), wherein the delay section (36) is a section of the at least one signal conductor (22) located on the first surface (26) of the substrate (20) between the substrate (20) and the cover (34), wherein the shifting device (32) comprises a shifting portion (38), the shifting portion (38) comprising a dielectric material, being located on a first side of the substrate (20), and covering the delay section (36) at least partly, wherein the shifting device (32) is movable with respect to the substrate (20) in a direction of motion (M) parallel to the first surface (26), wherein the cover (34) covers the delay section (36) at least in the vertical direction (V), wherein the cover (34) is electrically connected to the ground conductor (24), and wherein an exclusion area (60) of the second surface (28) is at least 75% free of the ground conductor (24), wherein the exclusion area (60) includes an area (Al) of the second surface (28) corresponding to a vertical projection of the delay section (36) onto the second surface (28).

2. Antenna according to claim 1, characterized in that the exclusion area (60) of the second surface (28) is at least 90%, in particular 100% free of the ground conductor (24), and / or at least 75%, in particular at least 90%, more particularly 100% free of a grounded conductor.

3. Antenna according to claim 1 or 2, characterized in that the at least one phase shifter assembly (18) comprises a longitudinal direction (L) and a transverse direction (T), wherein the exclusion area (60) has a width (wa) in the transverse direction (T) corresponding to the width (wi) of the delay section (36), corresponding to the width of the delay section (36) plus 10%, in particular plus 20%, corresponding to the width (W2) of the shifting device (32), and / or corresponding to the width of the base (41).

4. Antenna according to any of the preceding claims, characterized in that the at least one phase shifter assembly (18) comprises a longitudinal direction (L) and a transverse direction (T), wherein the exclusion area (60) has a length (la) in the longitudinal direction (L) corresponding to the length (h) of the delay section (36), corresponding to the length (h) of the delay section (36) plus 2%, in particular plus 5%, and / or corresponding to the length of the cover (34).

5. Antenna according to any of the preceding claims, characterized in that the at least one signal conductor (22) comprises feeding sections (56) galvanically connected to the delay section (36), wherein the ground conductor (24) forms a ground plane for the feeding sections (56).

6. Antenna according to claim 5, characterized in that the delay section (36) is galvanically coupled to one of the radiators (16) by one of the feeding sections (56).

7. Antenna according to claim 5 or 6, characterized in that the substrate (20) comprises at least one connecting via (58), and at least one of the feeding sections (56) galvanically coupled to the delay section (36) extends on the second surface (28) and is connected to the delay section (36) by one of the at least one connecting via (58), in particular both of the feeding sections (56) galvanically coupled to the delay section (36) extend on the second surface (28) and are connected to the delay section (36) by one of the at least one connecting via (58) each.

8. Antenna according to any of the preceding claims, characterized in that the cover (34) has a base (41), wherein the delay section (36) and the shifting portion (38) of the shifting device (32) are located between the base (41) of the cover (34) and the first surface (26) of the substrate (20); and / or in that the cover (34) comprises sidewalls (42), wherein the sidewalls (42) extend perpendicular to the first surface (26) of the substrate (20).

9. Antenna according to any of the preceding claims, characterized in that the cover (34) is attached to the first surface (26) of the substrate (20), in particular by attaching, for example soldering, the cover (34) to the ground conductor (24) on the first surface (26) of the substrate (20).

10. Antenna according to any of the preceding claims, characterized in that the exclusion area (60) includes an area (A2) of the second surface (28) corresponding to a vertical projection of the cover (34), in particular the base (41) of the cover (34), onto the second surface (28).

11. Antenna according to any of the preceding claims, characterized in that the substrate (20) comprises a plurality of mounting vias (46), and the cover (34), in particular sidewalls (42) of the cover (34), comprises fixation legs (44) extending through the mounting vias (46), wherein the exclusion area (60) ends spaced apart from the mounting via (46).

12. Antenna according to claim 11, characterized in that the cover (34) is attached to the substrate (20) by attaching the fixation legs (44) to the second surface (28) of the substrate (20), in particular attaching the fixation legs (44) to the respective mounting via (46) and / or the ground conductor (24) on the second surface (28) of the substrate (20).

13. Antenna according to any of the preceding claims, characterized in that the phase shifter assembly (18) comprises an actuating mechanism (48), wherein the actuating mechanism (48) is mechanically connected to an actuation portion (40) of the shifting device (32) and designed such that it is able to move the shifting device (32) in the direction of motion (M).

14. Antenna according to any of the preceding claims, characterized in that the shifting portion (38) comprises cutouts; and / or in that the cover (34) is made of a conductive material or provided with a conductive layer or coating.

15. Antenna according to any of the preceding claims, characterized in that the ground conductor (24) forms a reflector for the radiators (16), covers an area of the first surface (26) and / or second surface (28) corresponding to a vertical projection of the radiators (16) onto the respective surface, and / or surrounds the delay section (36) fully on the first surface (26).

16. Antenna according to any of the preceding claims, characterized in that the substrate (20) is a double-sided substrate, is a PCB, in particular of FR-2 or FR-4, and / or has a thickness smaller than 1 mm, in particular smaller than 0.8 mm.

17. Antenna according to any of the preceding claims, characterized in that the antenna (14) comprises a plurality of phase shifter assemblies (18), wherein the radiators (16) are arranged in columns parallel to the direction of motion (M), in particular wherein the phase shifter assemblies (18) are located between the radiators (16) of adjacent columns.

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

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