Antenna feeding network comprising coaxial lines with inner conductors connected by snap-on fingers and a multi-radiator antenna formed therefrom

Abstract

An antenna feeding network for a multi-radiator antenna, the antenna feeding network comprising at least two coaxial lines. Each coaxial line comprises a central inner conductor and an elongated outer conductor surrounding the central inner conductor. At least a first inner conductor and a second inner conductor of the at least two coaxial lines are indirectly interconnected.

Claims

1. An antenna feeding network for a multi-radiator antenna, the antenna feeding network comprising at least two coaxial lines, wherein each coaxial line comprises an inner conductor and an outer conductor, which is elongated and which surrounds the inner conductor, further comprising at least one connector device configured to indirectly interconnect at least the inner conductor of a first of said at least two coaxial lines and the inner conductor of a second of said at least two coaxial lines, wherein the at least one connector device is realized as a snap-on element comprising at least one pair of snap-on fingers and a bridge portion, wherein the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are connected to the bridge portion and wherein the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are adapted to be snapped onto the inner conductor of said first of said at least two coaxial lines or the second inner conductor of said second of said at least two coaxial lines, whereby the connector device is configured to be removably connected to the first inner conductor of said first of said at least two coaxial lines and the inner conductor of said second of said at least two coaxial lines, respectively.

2. The antenna feeding network according to claim 1, wherein the at least two coaxial lines are substantially air-filled coaxial lines, each coaxial line being provided with air between the inner and outer conductors.

3. The antenna feeding network according to claim 1, wherein said at least one connector device provides a capacitive or inductive connection between the inner conductor of said first of said at least two coaxial lines and the inner conductor of said second of said at least two coaxial lines, respectively.

4. The antenna feeding network according to claim 1, comprising at least one insulating layer, wherein the at least one insulating layer is arranged on the at least one connector device or on the first inner conductor of said first of said at least two coaxial lines or the inner conductor of said second of said at least two coaxial lines, respectively.

5. The antenna feeding network according to claim 1, comprising at least one insulating layer, wherein the at least one insulating layer is arranged between the at least one connector device and the inner conductor of said first of said at least two coaxial lines or the inner conductor of said second of said at least two coaxial lines, respectively.

6. The antenna feeding network according to claim 1 wherein said at least one pair of snap-on fingers and said bridge portion each comprises a core made of an electrically conductive material and an electrically insulating layer arranged around the core.

7. The antenna feeding network according to claim 6, wherein the insulating layer is a polymer layer or a non-conductive oxide material with a thickness of less than or equal to 50 μm.

8. The antenna feeding network according to claim 6, wherein the insulating layer is a polymer layer or a non-conductive oxide material with a thickness of at least 1 μm and no more than 20 μm.

9. The antenna feeding network according to claim 1, wherein said at least one pair of snap on fingers comprises at least two pairs of snap on fingers, wherein a first of the at least two pairs of snap on fingers of said at least one connector device are configured to be snapped onto the inner conductor of said first of said at least two coaxial lines and a second of said at least two pairs of snap on fingers are configured to be snapped onto the inner conductor of said second of said at least two coaxial lines, respectively.

10. A method for assembling an antenna feeding network for a multi-radiator antenna, said method comprising: providing at least two coaxial lines, wherein each coaxial line is provided with an inner conductor and an outer conductor, which is elongated and which surrounds the inner conductor; interconnecting at least the inner conductor of a first of said at least two coaxial lines and the inner conductor of a second of said at least two coaxial lines indirectly by connecting at least one connector device between said said inner conductors of said at least first and second of said at least two coaxial lines, wherein said least one connector device is realized as a snap-on element comprising at least one pair of snap-on fingers and a bridge portion, wherein the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are connected to the bridge portion and wherein the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are adapted to be snapped onto the inner conductors of said at least first or second of said at least two coaxial lines, whereby, the at least one connector device is adapted to be removably connected to the inner conductor of said first of said at least two coaxial lines and the inner conductor of said second of said at least two coaxial lines, respectively; and providing an insulating layer on said at least one connector device and/or on said inner conductors of said at least first and second of said at least two coaxial lines or providing said insulating layer between said at least one connector device and the inner conductor of said first of said at least two coaxial lines and the inner conductor of said second of said at least two coaxial lines, respectively.

11. The method according to claim 10, wherein said insulating layer is achieved by providing a thin insulating layer on the at least one connector device.

12. The method according to claim 10, wherein said insulating layer is achieved by providing a thin insulating layer on the inner conductors of said first and second of said at least two coaxial lines, respectively.

13. A multi radiator antenna comprising an electrically conductive reflector, at least one radiating element arranged on said reflector and an antenna feeding network, said at least one radiating element being connected to said antenna feeding network, said antenna feeding network comprising at least two coaxial lines, wherein each coaxial line comprises an inner conductor and an outer conductor, which is elongated and which surrounds the inner conductor, further comprising at least one connector device configured to indirectly interconnect at least the inner conductor of a first of said at least two coaxial lines and the inner conductor of a second of said at least two coaxial lines, wherein the at least one connector device is realized as a snap-on element comprising at least one pair of snap-on fingers and a bridge portion, whereby the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are connected to the bridge portion and wherein the snap-on fingers of said at least one pair of snap-on fingers of said at least one connector device are adapted to be snapped onto the inner conductor of said first of said at least two coaxial lines or the inner conductor of said second of said at least two coaxial lines, whereby the at least one connector device is configured to be removably connected to the first inner conductor of said first of said at least two coaxial lines and the inner conductor of said second of said at least two coaxial lines, respectively.

14. The multi radiator antenna according to claim 13, further comprising an insulating layer which is is a polymer material or a non-conductive oxide material with a thickness of at least 1 μm and no more than 20 μm.

15. The multi radiator antenna according to claim 13, wherein the electrically conductive reflector comprises at least one opening adapted to the size of the at least one connector device such that said at least one connector device can be installed via said opening.

16. The multi radiator antenna according to claim 15, wherein the at least one opening is located on a front side of said electrically conductive reflector.

17. The multi radiator antenna according to claim 15, wherein the at least one opening is located on a back side of said electrically conductive reflector.

18. The multi radiator antenna according to claim 13, wherein the at least two coaxial lines are each substantially air-filled coaxial lines, each coaxial line being provided with air between the inner and outer conductors.

19. The multi radiator antenna according to claim 13, wherein said at least first and second inner conductors are interconnected capacitively and/or inductively.

20. The multi radiator antenna according to claim 13, comprising at least one insulating layer, wherein the at least one insulating layer is arranged on the at least one connector device and/or on the inner conductor of said first of said at least two coaxial lines or the inner conductor of said second of said at least two coaxial lines, respectively.

21. The multi radiator antenna according to claim 13, comprising at least one insulating layer, wherein the at least one insulating layer is arranged between the at least one connector device and the first inner conductor of said first of said at least two coaxial lines or the inner conductor of said second of said at least two coaxial lines, respectively.

22. The multi radiator antenna according to claim 13, wherein said at least one pair of snap-on fingers, and said bridge portion each comprises a core made of an electrically conductive material and an electrically insulating layer arranged around the core.

23. The multi radiator antenna according to claim 13, further comprising an insulating layer which is is a polymer material or a non-conductive oxide material with a thickness of less than or equal to 50 μm.

24. The multi radiator antenna according to claim 13, wherein said at least one pair of snap on fingers comprises at least two pairs of snap on fingers, wherein a first of the at least two pairs of snap on fingers of said at least one connector device are configured to be snapped onto the inner conductor of said first of said at least two coaxial lines and a second of said at least two pairs of snap on fingers are configured to be snapped onto the second inner conductor of said second of said at least two coaxial lines, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, in which:

(2) FIG. 1 schematically illustrates a multi-radiator antenna;

(3) FIG. 2 schematically illustrates a perspective view of an embodiment of a multi-radiator antenna according to a second aspect of the invention;

(4) FIG. 3 schematically illustrates a perspective view of an embodiment of an antenna feeding network according to a first aspect of the invention;

(5) FIG. 4 schematically illustrates another perspective view of parts of an embodiment of an antenna feeding network according to the first aspect of the invention;

(6) FIG. 5 schematically illustrates a front view into two neighboring coaxial lines of an embodiment of an antenna feeding network according to the first aspect of the invention;

(7) FIG. 6 schematically illustrates parts of another embodiment of an antenna feeding network according to the first aspect of the invention; and

(8) FIG. 7 schematically illustrates parts of yet another embodiment of an antenna feeding network according to the first aspect of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(9) FIG. 1 schematically illustrates an antenna arrangement 1 comprising an antenna feeding network 2, an electrically conductive reflector 4, which is shown schematically in FIG. 1, and a plurality of radiating elements 6. The radiating elements 6 may be dipoles.

(10) The antenna feeding network 2 connects a coaxial connector 10 to the plurality of radiating elements 6 via a plurality of lines 14, 15, which may be coaxial lines, which are schematically illustrated in FIG. 1. The signal to/from the connector 10 is split/combined using, in this example, three stages of splitters/combiners 12. Turning now to FIG. 2, which illustrates a multi-radiator antenna 1 in a perspective view, the antenna 1 comprises the electrically conductive reflector 4 and radiating elements 6a, 6b, and 6c.

(11) The electrically conductive reflector 4 comprises a front side 17, where the radiating elements 6a-6c are mounted and a back side 19.

(12) FIG. 2 shows a first coaxial line 20a which comprises a first central inner conductor 14a, an elongated outer conductor 15a forming a cavity or compartment around the central inner conductor, and a corresponding second coaxial line 20b having a second inner conductor 14b and an elongated outer conductor 15b. The outer conductors 15a, 15b have square cross sections and are formed integrally and in parallel to form a self-supporting structure. The wall which separates the coaxial lines 20a, 20b constitute vertical parts of the outer conductors 15a, 15b of both lines. The first and second outer conductors 15a, 15b are formed integrally with the reflector 4 in the sense that the upper and lower walls of the outer conductors are formed by the front side 17 and the back side 19 of the reflector, respectively.

(13) Although the first and second inner conductors 14a, 14b are illustrated as neighboring inner conductors they may actually be further apart thus having one or more coaxial lines, or empty cavities or compartments, in between.

(14) In FIG. 2, not all longitudinal channels or outer conductors are illustrated with inner conductors, it is however clear that they may comprise such inner conductors.

(15) The front side 17 of the reflector comprises at least one opening 40 for installation of a connector device 8. The opening 40 extends over the two neighboring coaxial lines 20a, 20b so that the connector device 8 can engage the first and second inner conductors 14a, 14b.

(16) Although the invention is illustrated with two neighboring inner conductors 14a, 14b, alternative embodiments have an opening (not shown) that extends across more than two coaxial lines 20a, 20b and provide a connector device 8 than can bridge two or even more inner conductors. Such a connector device (not shown) may thus be designed so that the connector device extends over a plurality of coaxial lines between two inner conductors or over empty cavities or compartments. Such a connector device (not shown) may also be used to connect three or more inner conductors.

(17) In FIG. 3, an enlarged view of the opening 40 and the connector device 8 arranged therein is illustrated. The connector device 8 is clipped or snapped onto the first inner conductor 14a and the second inner conductor 14b thereby providing a removable connection between the first inner conductor and the second inner conductor. The connection between the first inner conductor 14a and the second inner conductor 14b is electrically indirect, which means that it is either capacitive, inductive or a combination thereof. This is achieved by providing a thin insulating layer of a polymer material or some other insulating material (e.g., a non-conducting oxide) on the connector device 8. The insulating layer may have a thickness of 1 μm to 20 μm, such as from 5 μm to 15 μm, such as from 8 μm to 12 μm, or may have a thickness of 1 μm to 5 μm. The insulating layer may cover the entire outer surface of the connector device 8 or at least the portions of the connector device 8 that engage the first and second inner conductors 14a, 14b.

(18) The connector device 8 comprises a bridge portion 32 and two pairs of snap-on fingers 30, 30′. One of the two pairs of snap-on fingers 30′ is arranged close to one end of the bridge portion 32 and the other of the two pairs of snap-on fingers 30 is arranged close to the other end of the bridge portion 32. The two pairs of snap-on fingers 30, 30′ may be connected to the bridge portion 32 via connecting portions configured such that the bridge portion 32 is distanced from the first and second inner conductors 14a, 14b. In other embodiments, the snap-on fingers 30, 30′ are connected directly to the bridge portion 32. The connecting portions, as well as the other portions of the connector device, are shaped to optimize the impedance matching of the splitter/combiner formed by the connector device and the coaxial lines. The shape, or preferably the diameter of the connecting inner conductors may also contribute to the matching of the splitter/combiner.

(19) As can be seen from FIG. 3, the vertical separating wall portion 22 is reduced to about two-thirds to three-quarters of its original height in the area of the opening 40 so that the connector device 8 does not protrude over the front side 17 of the electrically conductive reflector 4. In other embodiments, the wall portion 22 is reduced all the way to the floor of the outer conductors. The remaining height of the wall portion is adapted together with the other components, such as the connector device to optimize the impedance match.

(20) It may be possible (not shown in the figures) to provide only one pair of snap-on fingers, for example the pair of snap-on fingers 30′ engaging the first inner conductor 14a providing an indirect connection, and to contact directly the other end of the bridge portion 32 to the second inner conductor 14b without insulating layer or coating. Such a direct connection can be provided by connecting the bridge portion 32 to inner conductor 14b by means of a screw connection, by means of soldering, by making the bridge portion an integral part of inner conductor 14b, or by some other means providing a direct connection.

(21) FIG. 4 shows another view of parts of an embodiment of the antenna feeding network. The connector device 8 engages the first and second inner conductors 14a, 14b. The connector device 8 and the inner conductors 14a, 14b together form a splitter/combiner. When operating as a splitter, the inner conductor 14a is part of the incoming line, and the two ends of the inner conductor 14b are the two outputs of the splitter. The U-shaped dielectric element 9 can be moved along the inner conductor 14b, which, together with an outer conductor (not shown), forms first and second coaxial output lines on opposite sides of the connector device 8. The dielectric element, thus, has various positions along those coaxial output lines.

(22) First, consider the case when the dielectric element 9 is placed in a central position, equally filling the first and second output coaxial lines. When a signal is received at the input coaxial line 14a, the signal is divided between the first output coaxial line and the second output coaxial line, and the signals outputted from the two output coaxial lines is equal in phase. If the dielectric element 9 is moved in such a way that the first output coaxial line is filled with more dielectric material than the second output coaxial line, the phase shift from the input to the first output increases. At the same time the second output coaxial line would be filled with less dielectric material, and the phase shift from the input to the second output decreases. Hence, the phase at the first output lags the phase at the second output. If the dielectric element is moved in the opposite direction, the phase of the first output leads the phase of the second output. The splitter/combiner may thus be described as a differential phase shifter.

(23) FIG. 4 illustrates how the connector device 8 engages the first and second inner conductors 14a, 14b in circumferential recessed areas or grooves 42 of the first and second inner conductors 14a, 14b. These grooves may be used to position the connector device 8 correctly along the longitudinal direction of the inner conductors 14a, 14b.

(24) FIG. 5 illustrates a view into the first and second coaxial lines 20a, 20b where the connector device 8, bridging the first inner conductor 14a and the second inner conductor 14b is visible. The snap-on fingers 30, 30′ are not so well visible since the snap-on fingers 30, 30′ engage the first and second inner conductors 14a, 14b in areas with a smaller diameter than the rest of the first and second inner conductors 14a, 14b. FIG. 5 further illustrates that the bridge portion 32 is not extending beyond the front side 17 of the electrically conductive reflector 4.

(25) The embodiment of the connector device 8 has been described having a thin insulating layer on the connector device 8. It may however be possible to provide the first and second inner conductors 14a, 14b respectively with a very thin insulating layer of a polymer material and provide the connector device without any insulating layer. The insulating layer may cover the entire outer surface of the first and second inner conductors 14a, 14b, or at least the portions where snap-on fingers 30, 30′ of the connector device 8 engage the first and second inner conductors 14a, 14b. In other embodiments, an isolating material in the form of a thin foil is placed between the snap-on fingers 30, 30′ and the inner conductor 14.

(26) Further, the connector device 8 has been described illustrating a first and a second inner conductor 14a, 14b in the antenna arrangement 1 (FIG. 1). The antenna arrangement 1 may however comprise more than one connector device 8 and a plurality of inner conductors 14a, 14b.

(27) FIG. 6 schematically illustrates parts of another embodiment of an antenna feeding network according to the first aspect of the invention. In FIG. 6, a cross section view is shown of a first inner conductor 14a′ and a second inner conductor 14b′. The first inner conductor 14a′ comprises a cavity 50 extending axially into one end of the first inner conductor 14a′. The second inner conductor 14b′ comprises a rod-shaped protrusion 51 extending axially from one end of the second inner conductor 14b′. The protrusion 51 is adapted to extend into the cavity 50 of the first inner conductor. An insulating layer 52 is provided in and around the cavity to provide an indirect electrical connection between the conductors. In other embodiments, the insulating layer may be provided on the protrusion 51 or as a separate insulating film between the conductors. The insulating layer may be provided as a polymer material or some other insulating material (e.g., a non-conducting oxide) on either or both inner conductors 14a′ or 14b′, completely or partially covering inner conductors 14a′ or 14b′, or the insulating material may be provided as a thin insulating foil inserted between inner conductors 14a′ and 14b′.

(28) FIG. 7 schematically illustrates parts of yet another embodiment of an antenna feeding network according to the first aspect of the invention. In FIG. 7, a cross section view is shown of three inner conductors 14a″, 14b″ and 14c″ and a three-legged h-shaped connector device 8′. Each leg of the connector device 8′ is provided with a cavity 50a, 50b, and 50c extending axially into respective leg ends. The inner conductors 14a″, 14b″, and 14c′″ each comprises a rod-shaped protrusion 51a, 51b and 51c extending axially from one end of the inner conductors 14a″, 14b″, and 14c″. The protrusions 51a, 51b, and 51c extend into corresponding cavities 50a, 50b, and 50c of the connector device. Insulating layers 52a, 52b, and 52c are provided in and around the cavities to provide an indirect electrical connection between the conductors. In other embodiments, the insulating layers may be provided on the protrusions, or as separate insulating films between the conductors and the connector device. The h-shaped connector device 8′ may be mounted in a similar manner as the connector device 8, i.e. by reducing a separating wall between two adjacent outer conductors. In other embodiments, the connector device 8′ is provided with protrusions, and the inner conductors 14a″, 14b″, and 14c″ are provided with cavities.

(29) The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention. For example, the number of coaxial lines may be varied and the number of radiators/dipoles may be varied. Furthermore, the shape of the connector element (if any) and inner conductors and the placement of the insulating layer or coating may be varied. Furthermore, the reflector does not necessarily need to be formed integrally with the coaxial lines or may, on the contrary, be a separate element. The scope of protection is determined by the appended patent claims.