Antenna arrangement using indirect interconnection

Abstract

An antenna arrangement comprising an antenna feeding network, an electrically conductive reflector and at least one radiating element arranged on said reflector is provided. The antenna feeding network comprises at least one substantially air filled coaxial line, each coaxial line comprising a central inner conductor and an elongated outer conductor at least partly surrounding the central inner conductor, wherein at least one radiating element and at least one coaxial line are configured to interconnect indirectly.

Claims

1. An Antenna arrangement comprising an antenna feeding network, an electrically conductive reflector and at least one radiating element arranged on said reflector, the antenna feeding network comprising at least one substantially air filled coaxial line, each of the coaxial line comprising a central inner conductor and an elongated outer conductor surrounding the central inner conductor, wherein the at least one radiating element and the central inner conductor of said at least one coaxial line interconnect indirectly, wherein said at least one radiating element comprises a coupling element for interconnecting with the at least one central inner conductor, wherein the coupling element comprises a free end portion, wherein said at least one radiating element interconnects with said at least one central inner conductor via said free end portion, wherein said antenna arrangement further comprises a snap on mechanism, wherein the snap on mechanism comprises a snap on portion integrally arranged on the coupling element, at least in proximity of the free end portion, and a complementary snap on portion arranged on the inner conductor.

2. The antenna arrangement according to claim 1, wherein the at least one radiating element and the at least one coaxial line are configured to interconnect capacitively and/or inductively.

3. The antenna arrangement according to claim 1, further comprising at least one insulating layer arranged to provide the indirect interconnection.

4. The antenna arrangement according to claim 3, wherein the insulating layer is arranged on the coupling element and/or on said at least one inner conductor.

5. The antenna arrangement according to claim 3, wherein the insulating layer is placed between the coupling element and said at least one inner conductor.

6. The antenna arrangement according to claim 1, wherein said at least one inner conductor comprises a receiving cavity or through hole.

7. The antenna arrangement according to claim 1, wherein the free end portion is conically formed.

8. The antenna arrangement according to claim 1, wherein the coupling element comprises a conductor line portion, and wherein said free end portion is formed with a step at an end of said conductor line portion, said free end portion having a greater diameter than the conductor line portion, wherein said step forms said snap on portion.

9. The antenna arrangement according to claim 1, wherein the snap on mechanism comprises a snap on bracket comprising the complementary snap on portion, and wherein the snap on bracket is configured to be snapped around the at least one of the inner conductors.

10. The antenna arrangement according to claim 1, wherein the snap on mechanism comprises a dielectric support element configured to hold and at least partially surround the at least one of the inner conductors, wherein the dielectric support element comprises the complementary snap on portion.

11. The antenna arrangement according to claim 1, wherein the complementary snap on portion is realized in the form of snap on fingers, which are configured to engage the snap on portion when the free end portion is in an engaged position.

12. The antenna arrangement according to claim 1, wherein the electrically conductive reflector comprises an opening and wherein the coupling element extends through the opening to the inner conductor.

13. The antenna arrangement according to claim 1, wherein the snap on portion of said coupling element comprises a snap on bracket configured to engage with said complementary snap on portion arranged on said inner conductor.

14. The antenna arrangement according to claim 13, wherein said snap on bracket is formed at the free end portion of said coupling element as a pair of snap on fingers.

15. The antenna arrangement according to claim 14, wherein said complementary snap on portion is provided in the form of a portion of the envelope surface of said inner conductor.

16. The antenna arrangement according to claim 15, wherein said portion is formed as a recess in said envelope surface.

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 feeding network of an antenna arrangement;

(3) FIG. 2 schematically illustrates a perspective view of an embodiment of an antenna arrangement according to the first aspect of the invention;

(4) FIG. 3 schematically illustrates an embodiment of an antenna arrangement according to the first aspect of the invention, showing a perspective view onto a cross section cut through the middle of one of the radiating elements along a coaxial line;

(5) FIG. 4 schematically illustrates an embodiment of an antenna arrangement according to the first aspect of the invention, showing another perspective cross sectional view of the connection between the radiating element and the inner conductor, the cross section being cut perpendicular to the coaxial line;

(6) FIG. 5 schematically illustrates a view of a coupling element and an inner conductor of an embodiment of an antenna arrangement according to the first aspect of the invention;

(7) FIG. 6 schematically illustrates a cross section view of parts of an embodiment of an antenna arrangement according to the first aspect of the invention, which is provided with a snap-on mechanism; and

(8) FIG. 7 schematically illustrates a view of a coupling element and an inner conductor of an alternative embodiment of an antenna arrangement 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 an antenna arrangement 1 in a perspective view, the antenna arrangement 1 comprises the electrically conductive reflector 4 and the radiating elements 6.

(11) The electrically conductive reflector 4 comprises a front side 17, where the radiating elements 6 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 neighbouring 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) Each of the radiating elements 6 is configured to be electrically connected to at least one of the inner conductors 14 via a coupling element 24 (c.f. FIG. 3).

(16) The front side 17 of the reflector may comprise at least one opening 40 for the installation of a connector device 8. The opening 40 extends over the two neighbouring coaxial lines 20a, 20b so that the connector device 8 can engage the inner conductors 14a-b.

(17) FIG. 3 illustrates a perspective view onto a cross section cut through the middle of one of the radiating elements 6 in longitudinal direction of antenna arrangement. FIG. 3 also illustrates how the radiating element 6 is connected to one of the inner conductors 14. The radiating element 6 comprises a coupling element 24 having a conductor line portion 46 and a free end portion 48 at an end of the conductor line portion 46. The coupling conductor element 24 extends through the at least one opening 28 in the electrically conductive reflector 4 into a cavity or through hole 36 formed in the inner conductor 14.

(18) The cavity or through hole 36 and the free end portion 48 of the coupling conductor element 24 are both conically shaped having corresponding diameter and rise to achieve a tight fit. The cavity or through hole 36 extends through the entire inner conductor 14, but may in other embodiments only extend partially into the inner conductor 14.

(19) The coupling between the coupling element 24 and the inner conductor 14 is either capacitive, inductive or a combination therefore. This is achieved by providing a thin insulating layer on at least the free end portion 48 of the coupling element. In other embodiments, the cavity or through hole 36 comprises a thin insulating layer, while the free end portion does not. The insulating layer may have thickness of less than 50 m, such as from 1 m to 20 m, such as from 5 m to 15 m, such as from 8 m to 12 m. In other embodiments, both the free end portion 48 and the cavity or through hole 36 comprise a thin insulating layer. The thin insulating layer could be provided by applying a thin layer of a polymer material, or by having a thin oxide layer, or by some other provisions applying an isolating layer.

(20) The radiating elements 6 each comprise four identical radiating parts 6a-d forming a dipole. The radiating parts extend essentially in plane parallel with the antenna reflector. The radiating parts are fed using a balanced-unbalanced transformer 6e, also called a balun, which also forms a mechanical support for the radiating parts. As is further illustrated in FIG. 3, the balun comprises a body part 6e and the coupling element 24 which is positioned in the centre of a cylindrical hole in the body part. The body part 6e is connected to the outer conductor and to the antenna reflector.

(21) FIG. 4 illustrates another perspective cross sectional view of the connection between the radiating element 6 and the inner conductor 14. The cross section is cut through the connection. The coupling element 24 and its enlarged free end portion 48 are shown. The free end portion 48 is conically inverted shaped and comprises a step 35 between the free end portion 48 and the conductor line portion 46. The free end portion 48 has a greater diameter than the conductor line portion 46.

(22) Although the free end portion 48 has a conically inverted shaped it is conceivable that it has another shape such as cylindrical, cubical, etc. The shape of the cavity or through hole 36 may be adapted accordingly.

(23) FIG. 5 schematically illustrates the inner conductor 14 and the coupling conductor element 24 engaged in the cavity or through hole 36. As can be seen, the inner conductor 14 has a slightly greater diameter where the cavity or through hole 36 is shaped. This may be done for example for improved stability and/or a higher capacity of the indirect electric connection. The step 35 formed between the conductor line 46 and the enlarged free end portion 48 is also shown.

(24) FIG. 6 schematically illustrates a cross section view of parts of an antenna arrangement which comprise a snap on mechanism. The snap on mechanism has a snap on portion in the form of the step 35, which is integrally arranged on the coupling element 24 (only partially shown in the figure), above the free end portion 48, and a complementary snap on portion 49 arranged on the inner conductor 14. The complementary snap on portion 49 is formed as an edge of a dielectric support element 50 that is used to engage with and hold the inner conductor 14 in position within the outer conductor. The support element 50 is made from a plastic material which is slightly flexible which causes the opening in the spacer to widen slightly when the coupling element is pushed into the cavity or through hole of the inner conductor. After the coupling element has been pushed down, the edge/snap on portion 49 prevents it from accidentally leaving the cavity or through hole. In other embodiments, the complementary snap on portion is formed on a separate component which is not a dielectric support element.

(25) FIG. 7 schematically illustrates parts of an alternative embodiment of an antenna arrangement according to the first aspect of the invention. The figure shows an inner conductor 114 and a coupling conductor element 124 engaged with the inner conductor. The coupling element 124 is provided with a conductor line portion 146, wherein the free end portion is formed at an end of the conductor line portion, wherein a snap on portion is provided at the free end portion of the coupling element as a pair of snap on fingers 151 (only one is visible in the figure). The complementary snap on portion is provided in the form of a recessed portion 152 of the envelope surface of said inner conductor. The recessed portion has a smaller diameter than the adjacent portions of the envelope surface and has a length (in the longitudinal direction) which corresponds to that of the snap on fingers 151. The snap on fingers 151 may be described as a pair of protrusions configured to engage around the inner conductor, which fingers or protrusions may be configured to be flexible to allow the coupling element to be removably connectable to the inner conductor.

(26) The coupling between the coupling element 124 and the inner conductor 114 is either capacitive, inductive or a combination therefore. This is achieved by providing a thin insulating layer on at least the surface portions of the snap on fingers 151 which are in abutment with the inner conductor, or on the whole coupling element or snap on finger portion thereof. In other embodiments, the inner conductor 114, or at least the recessed portion 152 thereof, comprises a thin insulating layer, while the snap on fingers do not. The insulating layer may have thickness of less than 50 m, such as from 1 m to 20 m, such as from 5 m to 15 m, such as from 8 m to 12 m. In other embodiments, both the snap on fingers and the recessed portion comprise a thin insulating layer. The thin insulating layer could be provided by applying a thin layer of a polymer material, or by having a thin oxide layer, or by some other provisions applying an isolating layer.

(27) It is understood that the alternative embodiment shown in FIG. 7 and described above only differs in the above described details relating to the interconnection between the coupling element and the inner conductor. Apart from this, the description above relating to FIGS. 2-4 applies analogously to this embodiment.

(28) 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 coupling element 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, but may on the contrary be a separate element. The scope of protection is determined by the appended patent claims.