PASSIVE INTERMODULATION TEST LEAD

Abstract

The invention is directed to a cable assembly (1) comprising a coaxial cable (2) with an inner conductor (3) and a shield (4) and a dielectric (5) arranged between the inner conductor (3) and the shield (4). The cable assembly (1) further comprises an outer jacket (7) which encompasses the coaxial cable (2). One or several spacers (10) are arranged between the coaxial cable (2) and the outer jacket (7) such that the outer jacket (7) and the coaxial cable (2) are spaced a distance apart.

Claims

1. A cable assembly (1) comprising: a. a coaxial cable (2) with an inner conductor (3) and a shield (4) and a dielectric (5) arranged between the inner conductor (3) and the shield (4); b. an outer jacket (7) which encompasses the coaxial cable (2) at a certain distance; wherein c. at least one spacer (10) is arranged between the coaxial cable (2) and the outer jacket (7) such that the outer jacket (7) and the coaxial cable (2) are spaced a distance apart.

2. The cable assembly (1) according to claim 1, wherein the shield (4) comprises a layer of braided wires.

3. The cable assembly (1) according to claim 2, wherein layer of braided wires are tin-coated.

4. The cable assembly (1) according to claim 1, wherein the shield (4) is encompassed by a cable sheath (6).

5. The cable assembly (1) according to claim 1, wherein the at least one spacer (10) is attached to the cable sheath (6) of forms part thereof.

6. The cable assembly (1) according to claim 1, wherein spacers (10) are arranged at a distance (A) with respect to each other along the coaxial cable (2).

7. The cable assembly (1) according to claim 1, wherein the at least one spacer (10) is made from a shrink tube.

8. The cable assembly (1) according to claim 1, wherein the outer jacket (7) comprises an armour (8).

9. The cable assembly (1) according to claim 6, wherein the armour (8) comprises a wire spiral (9)

10. The cable assembly (1) according to claim 1, wherein the outer jacket (7) comprises a protective sleeve (9).

11. The cable assembly (1) according to claim 1, wherein the outer jacket (7) is movable along the length of the coaxial cable (2) with respect to the coaxial cable (2).

12. The cable assembly (1) according to claim 1, wherein a connector (13) is attached to a least one end of the coaxial cable (2).

13. The cable assembly (1) according to claim 1, wherein at least one bushing (12) is mounted on the coaxial cable (2).

14. The cable assembly (1) according to claim 13, wherein the at least one bushing (12) is mounted on the coaxial cable (2) in an area where the coaxial cable (2) exits the outer jacket (7).

15. The cable assembly (1) according to claim 13, wherein the at least one bushing (2) forms part of a connector (13).

16. The cable assembly (1) according to claim 13, wherein the at least one bushing (12) comprises or is interconnected to a first interface (14) suitable to receive a second interface (15) of one or several connectors (13).

17. The cable assembly (1) according to claim 12, wherein a first contact sleeve (25) is attached to the shield (4) of the coaxial cable (2) contributing to the electrical contact between the shield (4) and the outer conductor (22) of the connector (13).

18. The cable assembly (1) according to claim 1, wherein the outer jacket (7) is terminated by an end sleeve (16).

19. The cable assembly (1) according to claim 18, wherein the end sleeve (16) is suitable to receive the at least one bushing (12).

20. The cable assembly (1) according to claim 12, wherein at least at one end of the cable assembly (1) a handle (17) mechanically interconnects the outer jacket (7) and the related connector (13).

21. A PIM test cable comprising a cable assembly according to claim 1.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0012] The herein described invention will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the invention described in the appended claims. The drawings are showing:

[0013] FIG. 1 is a cable assembly in a side view;

[0014] FIG. 2 is the cable assembly in a front view;

[0015] FIG. 3 is the cable assembly in a segmented section view along section line B-B of FIG. 2;

[0016] FIG. 4 is detail C of FIG. 3;

[0017] FIG. 5 is one end of a cable assembly in a perspective view;

[0018] FIG. 6 is a section view of the cable assembly according to FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 shows a cable assembly 1 according to the invention in a side view. FIG. 2 shows the cable assembly in a front view and FIG. 3 shows a section view of the cable assembly along section line B-B as indicated in FIG. 2. FIG. 4 shows detail C as indicated in FIG. 3. FIG. 5 shows an end section of the cable assembly according to FIG. 1 and FIG. 6 shows the end section according FIG. 5 in a section view, such that the inside becomes partially visible.

[0020] As visible in FIG. 3 and FIG. 4 the cable assembly 1 comprises a coaxial cable 2 with an inner conductor 3, a shield (outer conductor) 4 and a dielectric 5 arranged between the inner conductor 3 and the shield 4. Furthermore the cable assembly 1 comprises a tubular outer jacket 7 which encompasses the coaxial cable 2 at a certain radial distance. Good results are achieved when the inner diameter of the outer jacket 7 is about 1.1 to 2 times of the outer diameter of the coaxial cable 2.

[0021] At each the end of the coaxial cable 2 a bushing 12 is mounted. This provides local stiffening and prevents negative kinking of the coaxial cable 2 especially in the area where the coaxial cable exits the outer jacket 7 and is not protected anymore. In the shown variation the coaxial cable 2 is at either end terminated by a connector 13 which are here attached to the coaxial cable 2 by a first and a second (standardized) interface 14, 15. This offers the advantage that the same cable assembly can be equipped with different types of connectors 13 and can thereby easily be adapted to different fields of application. If appropriate the bushings 12 can form part of a connector. On either end the outer jacket 7 is terminated by an end sleeve 16. The end sleeves 16 comprise an opening 18 which acts as guiding means for the therein arranged bushing 12.

[0022] As best visible in FIG. 4, the inside between the bushing 12 and the coaxial cable 2 is filled with a sealing compound 19. The sealing compound 19 is filled in by an filling opening 20 which is arranged here lateral at the bushing 12 such that during filling in the sealing compound 19 the space is thoroughly filled. If appropriate at least at one end of the cable assembly 1 the bushing 12, the end sleeve 16, the outer jacket 7 and the connector 13 can be encompassed by a handle 17. The handle 17 mechanically interconnects the several elements and safely prevents unwanted relative movement of the involved parts. Furthermore it transfers external load between the outer jacket and the connector 13 during operation and helps to securely protect the inside of the cable assembly, especially the coaxial cable 2. In a preferred embodiment the handle 17 is made out the same material as the sealing compound 19. E.g. the end of the cable assembly is inserted into a mold (not shown in detail) and the sealing compound is injected filling the space between the bushing 12 and the coaxial cable 2 by the opening 20 as well as the handle 17. After curing of the material the cable assembly 1 is removed from the mold. The radial distance between the outer jacket 7 and the coaxial cable 2 is defined by several spacers 10 which are arranged at an even distance 11 between the coaxial cable 2 and the outer jacket 7 along the coaxial cable 2. The shield of the coaxial cable can be single or multi layered. Good results are achieved by a shield 4 which comprises a layer of braided wires, e.g. silver-plated cooper braid, which are then tin-coated. However, depending on the field of application other shield types are possible.

[0023] In the shown variation the coaxial cable 2 comprises a cable sheath 6 is encompasses the shield 4. The spacers 10 are arranged attached to the outside of the cable sheath 6 such that they can inside the outer jacket 7 in length direction along with the coaxial cable 2. Alternatively or in addition at least one spacer 10 can be incorporated in the cable sheath, i.e. forming part thereof. This can be e.g. achieved by cable extrusion of melted plastic material forming the thin and the thick areas of the cable sheath. If appropriate the cable sheath 6 can have a constant thickness over its length. In a very simple manner the spacers 10 can e.g. be made from shrink tube which is placed onto the outer sheet 6 of the coaxial cable 2 and fixed by shrinking. Alternatively or in addition the spacer can e.g. be made from a reversible deformable foam material. Good results are achieved when several spacers 10 are arranged at defined distances 11 along the length of the coaxial cable 2. Smooth bending can be achieved when the spacers 10 are arranged at a distance A apart which corresponds about 20 to 120 times to the outer diameter of the coaxial cable. In a variation the spacer 10 itself may comprise one or several helical coils which extend at least partially along the coaxial cable 2.

[0024] As best visible in FIG. 4 the outer jacket 7 comprises an armour 8 which protects the coaxial cable 2 arranged on the inside against outer forces or over bending. Good results are achieved when the armour comprises a wire spiral 8 preferably made out of steel or another appropriate material and which allows easy bending without negative transformation of the cross section. To prevent damage of the coaxial cable the wire spiral 9 can be coated on the inside or embedded in a side wall of the armour 8. The outer jacket 7 here further comprises a protective sleeve 9 which protects the inside of the cable assembly 1 and prevents over stretching. If appropriate the armour 8 can be embed in the protective sleeve 9.

[0025] In the shown embodiment the connector 13 comprises a here male inner conductor 21 which is held within a housing (outer conductor) 22 by an insulator 23. Both are press-fit within the housing 22. At the rear end the connector 13 comprises a standardized interface 15 which comprises a first thread which can be can be engaged with a corresponding second thread of a corresponding standardized interface attached to an end of the coaxial cable 2. On the outside the connector 13 comprising fixing means, here in the form of a locking nut 24. As the connector 13 is detachable from the coaxial cable 2 by the standardized interfaces 14, 15 is possible to equip the cable assembly 1 easily with different types of connectors 13 as indicated in FIG. 3 on the right hand side.

[0026] As best visible in FIG. 4 in the shown variation a first contact sleeve 25 as attached to the end of the shield 4 of the coaxial cable 2. The contact sleeve 25 provides electrical contact between the shield 4 and the connector 13 and is normally attached alter the bushing 12 is slid on the coaxial cable 2. In the area where the contact sleeve 25 is applied, the cable sheath 6 is removed. Alternatively or in addition a second contact sleeve 26 can be foreseen. In the shown variation a second contact sleeve 26 is attached to the inner conductor 3. The second contact sleeve 26 provides electrical contact between the inner conductor 3 and the inner conductor 21 of the connector 13. This is advantages especially when the inner conductor 3 is a braided inner conductor.

[0027] Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the Spirit and scope of the invention.