# Patent

## Title
HF coaxial cable with angular plug connection, and a method for producing same

## Abstract

The invention is characterized in that a HF coaxial cable is designed as a conventional corrugated sheath cable comprising a cable outer conductor, in the form of a metal corrugated tube, having a line impedance Zk and a minimum bending radius rk,min specified by the manufacturer as a characteristic feature of the coaxial cable; in corrugated sheath cable, directly or indirectly following the straight plug connector, is bent to have a bending radius rα, where 0.2 rk,min≦rα≦0.9 rk,min, which alters the line impedance Zk by a maximum of 1 ohm. The bend with the bending radius rα is produced by cold forming corrugated sheath cable with the introduction of bending forces and tensile forces directed along said corrugated sheath cable.

## Background
CROSS REFERENCE TO RELATED APPLICATION
Reference is made to German Application DE 102 012 4425.3, filed Jul. 20, 2012 and PCT Application PCT/EP2013/002153, filed on Jul. 19, 2013, which applications are incorporated herein by reference in their entirety.
TECHNICAL FIELD
The invention relates to an HF coaxial cable that comprises a cable inner conductor and a cable outer conductor, as well as an angular plug connection at at least one of its two cable ends.
PRIOR ART
HF angular plug connections of the above type allow a substantially loss-free HF signal redirection, preferably by 90°, and are typically used for purposes of HF signal coupling into or HF signal coupling out of HF device components. Particularly advantageous is the only small overall height of such angular plug connections, which enables a reliable HF signal connection for the first time, principally in narrow installation spaces, as are often prevalent on the rear walls of devices.
An HF coaxial angular plug connector of the generic type is described in the published document DE 198 54 503 C1, which provides a plug connector inner conductor, which is centered by means of an insulating support of dielectric material within a metal housing, which at the same time constitutes the plug connector outer conductor. A receptacle opening for an HF coaxial cable assembled at the front is provided at right angles to a housing axis that can be allocated to the metallic housing. For the purpose of securely joining the cable inner and outer conductors to the corresponding inner and outer conductor regions provided on the housing side, an access opening that can be closed at the side on the metallic housing is provided, through which soldered connections between the respective inner and outer conductors have to be undertaken, but which are viewed as complicated installation steps and thus contribute a considerable portion of the production costs.
An angular plug connection for high-frequency coaxial cables is known from DE 38 36 141 A1, which can be realized with lower production costs owing to the simpler construction thereof. The known angular plug connection to this end provides a flexible HF coaxial cable. The cable outer conductor is a wire mesh and the assembled cable end thereof is connected to a specially shaped straight plug connector. The plug connector has a contact sleeve surrounding the cable outer conductor, which has a sleeve opening, which makes it possible to bend the sleeve region including the inner coaxial cable through 90°. The bending of the sleeve regions ensures that the cable inner conductor retains its insulation in the region of the angling. The radius of curvature of cable inner conductor and cable outer conductor is dimensioned such that the wave impedance of the coaxial cable remains constant, particularly in the region of the kink. For the purposes of plug stabilization, protection and also improved handling, the ready-installed plug is encapsulated with a corresponding plastic coating.
The coaxial cable described in the published document DE 103 50 763 A1 provides a similarly simple construction with an angular plug connection, in which the redirection through 90° for the HF signal line is realized by bending a flexible coaxial cable. In this case, the assembled coaxial cable end is connected to a straight plug connector, which is known per se. The HF coaxial cable set thereof, which protrudes directly out of the plug connector, has a 90° bend. A moulded part of a thermoplastic is used for maintaining the shape thereof. The flexible HF coaxial cable has an outer conductor formed from a metal mesh.
The published document DE 18 01 189 A discloses a right-angled coaxial-cable connector, with reduced electrical losses. Reference is expressly made to the fact that electrical losses increase in the case of deformations of a coaxial cable with radii that are too narrow. It is suggested to bend the coaxial cable in a gentle arc. A slot-shaped recess additionally is introduced in a plug housing part. Through the recess the cable is formed in the forming region into a gentle arc to the greatest extent possible.
The published document FR 2 503 942 A1 is concerned with the production of a bent semi-rigid cable, avoiding mechanical and electrical discontinuities in the outer conductor, which can occur in the form of microtears due to the deformation process, to the greatest extent possible. It is suggested to electrolytically coat the outer conductor after the bending of the semi-rigid cable, e.g. with a layer thickness of 2.2 mm, in order to improve the electrical properties.
Finally, the published document DE 30 48 781 A1 discloses a flexible coaxial cable with an outer-conductor mesh constructed as an outer conductor. It is suggested to remove the outer layer of the coaxial cable in the bending region, so that the outer conductor mesh is exposed. Subsequently, the coaxial cable is bent and the bend is fixed by a setting material. Solders or resin-based adhesives are preferred as setting material.
SUMMARY OF THE INVENTION
The invention is based on developing a HF coaxial cable including a cable inner conductor, a dielectric layer surrounding and contacting the cable inner conductor and a corrugated metal cable outer conductor surrounding and contacting the inner dielectric layer and an angular plug connector attached at at least one of two cable ends thereof so that the production outlay is reduced, and high-frequency signal transmission properties are improved significantly, particularly at high frequencies, for example greater than 4 GHz. It is necessary that the sizes, that is to say particularly the overall heights of hitherto-known angular plug connectors are not exceeded, but rather are reduced by providing a bending radius less than a manufacturer specified bending radius which is a characteristic feature of the HF coaxial cable along with the line impedance Zk. It is possible to implement this cable in terms of process engineering, simple means, particularly of assembling factories. Also, the diversity of parts required to be stocked for producing the angular plug connection, the logistics and storage outlay should be reduced considerably.
A HF coaxial cable constructed according to the invention has a conventional corrugated sheath cable, which is known per se, having a cable outer conductor constructed as a metal corrugated tube surrounding and contacting a dielectric layer and a cable inner conductor surrounded by and contacted by the dielectric layer, having a line impedance Zk and also a minimum bending radius rk,min, which are determined and specified by the cable manufacturer. A straight plug connector is attached at at least one cable end. For connection to the plug connector, the at least one cable end of the corrugated sheath cable is assembled. The cable inner conductor exposed at the end is joined with an inner conductor of the straight plug connector and the cable outer conductor is joined with an outer conductor of the straight plug connector. Directly or indirectly following the joining of the plug connector, to the cable inner conductor, the corrugated sheath cable is bent to a bending radius rα, which is significantly smaller than the minimum bending radius rk,min specified by the cable manufacturer. In accordance with the invention, significantly smaller means a bending radius rα, for which the following applies: 0.2 rk,min≦rα≦0.9 rk,min, preferably 0.3 rk,min≦rα≦0.7 rk,min, particularly preferably 0.4 rk,min≦rα≦0.6 rk,min.
In addition, the bent corrugated sheath cable dimensioned according to the invention has a line impedance Zα, for which the following applies:

|Zα−Zk|≦1Ω

That is in spite of bending the corrugated sheath cable with a significantly smaller bending radius rα which is less than the predetermined manufacturer's bending radius rk,min, the HF coaxial cable with angular plug connection according to the invention has HF transmission qualities, which correspond or at least substantially correspond to those of an undeformed corrugated sheath cable. The HF coaxial cable according to the invention is therefore characterized in particular by having a bending radius rα, which is produced by cold forming the corrugated sheath cable with the introduction of a bending force transversely to the corrugated sheath cable and also a tensile force along the corrugated sheath cable. The mutually adjusted introduction of bending and tensile forces ensures that the corrugated sheath cable geometry, which is characteristic for a loss-free HF signal propagation along the corrugated sheath cable, is not or at least is not appreciably changed by the bending. The corrugated sheath geometry characteristic for the HF signal propagation is in particular understood to mean an electrically effective diameter of the corrugated sheath cable, which corresponds to half the sum of one maximum and minimum diameter in each case that can be allocated to the cable outer metallic corrugated conductors, which are constructed in a corrugated manner. For an unhindered HF signal propagation along the corrugated sheath cable section bent according to the invention, the electrical diameter of the corrugated sheath cable deviates in the region of the bending radius rα by less than 10% from the electrical diameter in a remaining non-bent or shaped corrugated sheath cable region.
Due to the bending of the corrugated sheath cable according to the invention with the required bending radii rα far below the minimum bending radii rk,min specified by the manufacturer, the invention uses known HF coaxial cable angular plug connections, in which the HF signal propagation direction at 90° is realized by bending a correspondingly flexibly configured coaxial cable. The invention goes beyond technically acceptable use limits imposed by the manufacturer in the case of corrugated sheath cables by not undershooting a predetermined minimum bending radii. The significant undershooting of the bending radius initially creates the prerequisite of creating compact overall heights for the construction of an angular plug connection based on a corrugated sheath cable, which has overall heights comparable with the overall heights of conventional angular plug connections. However, due to the use of corrugated sheath cables bent according to the invention, in contrast with conventional coaxial cables with angular plug connections, in addition to a simpler installation or production of the angular connection, explained hereinafter, significantly better signal transmission qualities result, particularly in the case of frequencies of greater than 4 GHz.
The HF coaxial cable with an angular plug connection according to the invention can fundamentally be realized with corrugated sheath cables of all standardized diameter classes from 1⁄8′′ to 5⁄8′′. Thus, for corrugated sheath cables with a nominal diameter of 1⁄8′′, a minimum bending radii rα of 4 mm to 10 mm can be realized according to the invention with the minimum bending radius rk,min specified by the manufacturer typically being specified as 18 mm. In the case of “1⁄4” corrugated sheath cables, minimum bending radii rα of 5 mm to 15 mm can be manufactured with rk,min typically being 25 mm. For corrugated sheath cables with a nominal diameter, of 3⁄8′′, a minimum bending radii rα of 7 mm to 20 mm can be realized, for which a minimum bending radius rk,min of 25 mm being specified by the manufacturer. Finally, for 1⁄2′′ corrugated sheath cables, a minimum bending radii rα between 9 and 25 mm can be realized with rk,min at 32 mm being specified by the manufacturer. All commercially available corrugated sheath cables are fundamentally suitable for realizing a HF coaxial cable with angular plug connector according to the invention which relates to standardized corrugated sheath cables, particularly also super-flexible corrugated sheath cables, which have a spiral-corrugated outer conductor contour, that is with a pitch.
To produce the HF coaxial cable with angular plug connection according to the invention, at least one cable end needs to be assembled initially and the cable outer conductor and also the cable dielectric are trimmed with respect to the cable inner conductor. If present, the cable sheath protecting the HF corrugated sheath cable is likewise trimmed in certain areas.
In a next step, a straight plug connector is securely connected to the previously explained prepared cable end by joining the cable inner conductor to the inner conductor of the straight plug connector and the cable outer conductor to an outer conductor of the straight plug connector, preferably by soldering, crimping or similar joining methods. Of course, releasably secure joining techniques can also be used. For example, the cable inner conductor can be connected to a plug-side inner conductor structure by laminating or spring-loaded contacting. The installation outlay required for this is far lower compared to angular plug connectors composed of a plurality of components, as are known from the published document DE 198 54 503 C1 discussed above.
Subsequently, it is necessary to bend the corrugated sheath cable emanating from the plug connector in a straight line in one region which preferably directly follows the plug connector. The bending process takes place by means of cold forming under the action of a bending force directed transversely to the longitudinal extension of the HF corrugated sheath cable and a tensile force orientated longitudinally to the HF corrugated sheath cable, in such a manner that the corrugated sheath cable experiences a permanent bend with a bending radius rα, where rα≦rk,min, directly or indirectly following the straight plug connector. This bending alters the line impedance Zk of the straight-running, undeformed corrugated sheath cable by a maximum of 1 ohm, as a result of which the return loss ar of the conventional corrugated sheath cable can be changed as a function of the frequency by up to 2% due to the bend of the bending radius rα.
The tensile force additionally acting along the corrugated sheath cable as a function of the bending force acting on the corrugated sheath cable is chosen to provide a stretching of the corrugation contour of the cable outer conductor facing radially inwards to the bending radius on the one hand, so that a direct mutual bearing of adjacent corrugated structure side faces is counteracted. But on the other hand, the formation of tears, owing to overextension or overstretching, on the outer conductor surface radially outwardly facing the bend is eliminated.
Optionally, the cold formed bending region of the corrugated sheath cable is provided with an envelope, which exerts both a protection and support function for the bent region of the HF corrugated sheath cable. The bent cable region with the plug connector connected thereto is advantageously inserted into a correspondingly prefabricated casting mould and in a subsequent moulding process, is provided with a corresponding envelope using a suitably chosen thermoplastic material. Depending on the functional demand, the bent corrugated sheath cable region can alternatively be protectively surrounded with a hot adhesive, a shrink-fit hose or a suitably constructed protective sleeve.
With the previously described method, HF angular plug connectors can be realized, which are characterized by the use according to the invention of a HF corrugated sheath cable whose bend according to the invention, which is created by cold forming, has a significantly smaller bending radius than the minimum bending radius permitted by the manufacturer in each case. Thus, for example, an angular plug connector constructed according to the invention using a 1⁄4′′ corrugated sheath cable has an overall height of just approx. 40 mm. Although an overall height of this type can be realized with conventional angular plug connections, it cannot be realised using a conventional straight plug connection on a corrugated sheath cable, which would be bent minimally in accordance with manufacturer instructions and would furthermore permanently have HF transmission qualities that comply with the technical standard.
In another embodiment, the region of the cable is not bent directly following the straight plug connector along the corrugated sheath cable. Instead, the bend is rather in a suitable region, which lies spaced apart from the at least one plug connector attached to the cable at the end. Although the main aspect of the HF coaxial cable with angular plug connection according to the invention typically provides a bending angle β of 90° with a tolerance range of ±5°, i.e. 85°≦β≦95°, bends along the corrugated sheath cable are also conceivable with bending angles, β, which deviate therefrom, for example β=60°.
The dimensional shape of the angular plug connection and associated therewith the bending angle can be permanently fixed, for example by providing thermoplastically injection moulded geometries at the manufactured angular plug connection like webs, bulges, lobes, sieve-like structures. These geometries do not require additional effort and can be used for further functions like labels, attached caps, embedded functional parts etc.
Also, a plurality of bending regions can clearly be provided along a HF corrugated sheath cable, using the suggested cold forming method.



BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described by way of example in the following without limitation of the general inventive idea on the basis of exemplary embodiments with reference to the drawings. In the figures:
FIG. 1 shows a longitudinal section through an HF coaxial cable with an angular plug connection constructed according to the invention;
FIG. 2 shows a longitudinal section through a bent corrugated sheath cable for illustration of the electrical diameter;
FIG. 3 shows a longitudinal section through a straight plug connector attached on the cable end of a corrugated sheath cable;
FIGS. 4a-c show a sequential image illustration for cold forming according to the invention of the corrugated sheath cable with straight plug connector;
FIG. 5 shows an alternative bending device for a corrugated sheath cable for producing the smallest bending radii; and
FIG. 6 shows a graph for comparing the standing wave ratio between a straight connection, a bent embodiment according to the invention and a conventional angular plug connection with mountable plug connection.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a longitudinal sectional illustration for an HF coaxial cable with an angular plug connection constructed according to the invention. The HF coaxial cable used according to the invention constitutes a conventional corrugated sheath cable 1, which has a cable outer surrounding metallic conductor 2, which is corrugated in a spirally undulated manner. An inner cable conductor 4, which is guided centrally to the cable outer conductor 2 is surrounded by and contacts a cable dielectric 3. The cable outer conductor 2 is typically encapsulated by a plastic envelope 5.
The cable end of the corrugated sheath cable 1 of FIG. 1 has a protruding end 41 of the cable inner conductor 4 opposite a trimmed cable dielectric 3 and a cable outer conductor 2. The end 41 of the cable inner conductor 4 leads into a receptacle opening inside an inner conductor 42 provided on the plug side which is gripped in a component 7 to provide electrical insulation with respect to a plug-side outer conductor 6. The end of the cable outer conductor 2 is surrounded on the outside by an accommodating sleeve 61 of the plug outer conductor 6, and is securely joined to the same, preferably by means of a solder connection 62. A union nut 8 is additionally attached externally on the plug outer conductor 6 such that it can move longitudinally and cannot be lost. The plug connector S, which is securely connected to the corrugated sheath cable 1 at the end in FIG. 1, constitutes a straight plug connector that is known per se. It is possible to use customary joining techniques that are simple to master for the attachment thereof on the prefabricated cable end of the corrugated sheath cable 1. In addition, an envelope 10 is provided around the bent region of the corrugated sheath cable 1, which is not covered with the cable covering 5. The envelope can preferably be produced by a thermoplastic forming process and in addition to it providing a mechanical support function, the thermoplastic also ensures a sealing and protecting function with respect to external influences.
The novelty of the angular plug connection illustrated in FIG. 1 on the one hand lies in the use of the corrugated sheath cable 1, on the assembled cable end to which a straight a conventional plug connector S is attached with the corrugated sheath cable 1 having a bend, having a uniform bending radius rα. The bending radius according to the invention is chosen to be significantly smaller than a minimum bending radius rk,min specified as a minimum by the manufacturer of the corrugated sheath cable 1. Only by significantly undershooting the minimum bending radius rk,min permitted by the manufacturer can an angular plug connection be achieved, with the overall height h corresponding to or undercutting the dimensions of known angular plug connections being reduced relative to a height that would be achieved if rα was equal to rk,min.
The actually achievable bending radius rα is dimensioned on a circumferential contour facing the inward bend along the cable outer conductor 2, which comes into contact with a correspondingly fitted bending tool, as is also described below. Additional application-specific properties can be realized with the envelope.
The bending of the corrugated sheath cable 1 takes place in a cold forming process, which is performed with sufficient care to not impair the electrically effective diameter de. The electrically effective diameter de for a corrugated sheath cable 1, which has a decisive influence on the HF signal transmission along the corrugated sheath cable 1, is composed of half of the sum of the maximum and minimum diameter of the corrugated sheath cable 1 resulting from the corrugated cable outer conductor structure thereof.
The dielectric diameter de is illustrated with two dashed lines l1 and l2 in FIG. 2 which is a longitudinal section of a bent corrugated sheath cable 1. The cable 1 is connected at one end to a straight plug connector S, which is explained in more detail in conjunction with FIG. 1. Both dashed lines l1 and l2 run centrally through the corrugated cross-sectional contour of the cable outer conductor 2. In order to retain the required unchanged HF transmission qualities along the corrugated sheath cable 1 in spite of significant undershooting of the minimum bending radius rk,min defined by the manufacturer, it is necessary to carry out the bending along the corrugated sheath cable 1 with unchanged dielectric diameter de. The electrically effective diameters de at the representatively indicated cable points A, B, C, D are ideally identical. A tolerable deviation of the actual cable diameter at the points C, B compared to a non-bent cable region, for example A, D may be 10% at most.
To produce the angular plug connection according to the invention, a straight end of a corrugated sheath cable 1 is prepared and provided by trimming the outer cable sheath 5 as far as the cable sheath end 51 of the cable outer conductor 2 and of the cable dielectric 3, as it were, with respect to the cable inner conductor 4 (cf. FIG. 3). It may only be mentioned for the sake of completeness that the cable sheath 5 is only shortened as far as the cable sheath end 52 if no subsequent bending of the cable sheath 1 takes place.
Subsequently, a conventional straight plug connector S can be joined to the assembled cable end. The plug inner conductor 42 may be securely connected, for example by soldered or crimped, to the exposed cable inner conductor 4. Subsequently, the plug outer conductor 6 is pushed on or alternatively screwed on and soldered, clamped, welded or otherwise securely connected to the cable outer conductor 2. In this case, the straight plug connector S can be completed in advance, for example using a union nut 8, an insulating component 7 or, if necessary, using a seal 9. Alternatively, the straight plug connector S can be a plug, as a coupler or in a hybrid manner.
The cold-forming procedure takes place in the next step, which is explained with reference to the FIGS. 4a to c on the basis of a first exemplary embodiment. A retainer 12 is illustrated in FIG. 4a, which has a receptacle opening 13, which is adapted in an oppositely contoured manner to a supporting section of the plug connection S, so that the straight plug connector S is releasably fixed in a secure manner relatively to the retainer 12, which is attached in a stationary manner. A bending guide 14 adjoins the retainer 12 on one side along the corrugated sheath cable 1. The bending contour of the bending guide 14 corresponds to a predetermined bending radius rα. The corrugated sheath cable 1 is connected to a clamping and tensioning device 15 at a distance from the retaining means 12. The clamping and tensioning device creates both a tensile force Fz orientated longitudinally along the cable longitudinal extent L and a bending force Fr directed transversely to the cable longitudinal extent L onto the corrugated sheath cable 1, as is illustrated in FIG. 4b. Here, the clamping/tensioning element 15 including corrugated sheath cable 1 is guided around the bending guide 14 in a force-loaded manner, so that the region of the corrugated sheath cable 1 divested of the cable sheath 5 clings to the surface of the bending guide 14 in the manner illustrated in FIG. 4b. 
The bending process is ended as soon as the clamping/tensioning element 15 has cold formed the corrugated sheath cable 1 by 90°, as is illustrated in FIG. 4c. 
The bending guide 14 advantageously has a concavely constructed contact surface. In use the bending guide 14 comes into contact with at least one eighth and preferably up to a half of the circumferential edge of the corrugated cable outer conductor of the corrugated sheath cable 1. The concave construction of the bending guide 14 supports the shape retention of the cross-sectional geometry of the corrugated sheath cable 1 and, connected therewith, the constant electrically effective diameter de during the cold forming process.
The adaptation of the forces Fz and Fr acting on the corrugated sheath cable 1 during the cold forming process is of central importance. In particular, during the choice of the tensile force Fz acting along the corrugated sheath cable 1, it is necessary to note that the inner surfaces 16 and 17 of two corrugated guides (cf. FIG. 2), which directly face the bending guide 14, are spaced apart from one another by a corresponding stretching action and not pressed together by the bending process. On the other hand, the tensile force Fz must not lead to tears or other material degradations forming on the side of the cable outer conductor 2 facing away from the bending guide 14. Thus, the force contribution of the bending process and acting on the corrugated sheath cable, which is composed of the sum of tensile force Fz and bending force Fr, is chosen individually in each case as a function of size and material type and also of the material composition of the corrugated sheath cable. The forming on the one hand constitutes a plastic forming, providing the desired, bent spatial form of the corrugated sheath which is retained without further force contribution, and on the other hand does not lead to any of the previously described material degradations.
FIG. 5 shows an alternative bending tool with a stationarily attached bending guide 11, to which a retaining means 18 is pivotably attached, into which the straight plug connector S can be inserted in a fixed manner such that it cannot be released. A rolling or sliding body 19 is provided together with the retainer 18 attached such that it can pivot about the bending guide 11 to which the rolling or sliding body is attached radially spaced apart from the circumferential edge of the bending guide 11. During the pivoting process, the rolling or sliding body 19 exerts a contact force onto the corrugated sheath cable 1, which is directed orthogonally onto the bending guide 11 which causes the corrugated sheath cable 1 to be cold formed on the basis of the bending contour of the bending guide 11. Along the corrugated sheath cable 1, the corrugated sheath cable 1 is pressed against a likewise stationarily attached guide unit 20 with a retaining force FR. As a result, the corrugated sheath cable 1 experiences a tensile stress orientated along the corrugated sheath cable, which together with the bending force leads to the cold forming according to the invention. In this case also, it is necessary to choose the retaining force FR, by means of which the tensile and bending forces explained in connection with the FIGS. 4a to 4c are predetermined, in such a manner that a forming, which is plastic and maintains the corrugated outer contour of the corrugated sheath cable, is achieved, with there being no considerable deformation or material degradations, which influence the HF transmission properties of the bent corrugated sheath cable, occur.
In FIG. 6 a graph is shown for comparing the standing wave ratio between a straight (Function 1), a corrugated sheath cable bent according to the invention with angular plug connector (Function 2), and a conventionally bent angular plug connection with mountable plug connector (Function 3). The standing wave ratio is a measure for the standing wave, which arises along a waveguide due to reflection. In the case of a standing wave ratio close to the value 1, virtually the entire HF power fed in is transmitted through the transmission line into a load. This is the desired state if the line is used for energy transmission. With increasing values of the standing wave ratio, the reflected portion increases and thus the loss increases. In the illustrated graph, the so-called electrical voltage standing wave ratio (VSWR) is shown along the ordinate as a function of the frequency f of 0 to 6000 MHz, which is entered along the abscissa.
Starting from a straight, unbent corrugated sheath cable, to which a straight connector is attached to feed in a HF signal, VSWR values from close to 1 up to 1.04 maximum are shown. Using a corrugated sheath cable bent according to the invention, VSWR values in the range of 1 and maximum of 1.08 in the specified frequency range of 0 to 6000 MHz can be achieved. By contrast, in the case of a corrugated sheath cable conventionally assembled with an angular plug, a clear increase of the VSWR value is shown at frequencies from approximately 4500 MHz.
In addition, the simple structure of the angular plug connector formed according to the invention opens up, in view of a reduced number of parts, a significant reduction of intermodulation risks that occur definitely in conventionally formed angular plug connectors already due to their complex and multi-component structure.
REFERENCE LIST


    1 Corrugated sheath cable
    2 Cable outer conductor
    3 Cable dielectric
    4 Cable inner conductor
    41 End of the cable inner conductor
    42 Plug inner conductor
    5 Cable sheath
    51 Cable sheath end for angular plug connection
    52 Cable sheath end for straight plug connection
    6 Plug external conductor
    61 Accommodating sleeve
    62 Solder connection
    7 Insulating support
    8 Union nut
    9 Seal
    10 Covering
    11 Bending guide
    12 Retaining means
    13 Recess
    14 Bending guide
    15 Clamping/tensioning element
    16 Internal surface of a cable outer conductor corrugated guide
    17 Internal surface of a cable outer conductor corrugated guide
    18 Retaining means
    19 Rolling or sliding body
    20 Guide unit
    S Plug connector
    h Overall height
    Fz Tensile force
    Fr Bending force
    FR Retaining force

## Claims

1. A method for producing a high-frequency (HF) coaxial corrugated cable including a plug connector located at at least one of two ends, a cable inner conductor, a dielectric layer surrounding and contacting the cable inner conductor and tubular metallic corrugated outer conductor surrounding and contacting the dielectric layer comprising:
providing a HF corrugated coaxial cable including a tubular metallic corrugated outer conductor which centrally surrounds a cable inner conductor and a dielectric layer, the HF corrugated coaxial cable having characteristic features including line impedance Zk, and a minimum bending radius rk,min specified by a manufacturer;
trimming an end of the HF corrugated coaxial cable to provide access to the cable inner conductor, the dielectric layer surrounding and contacting the inner cable conductor and the metallic outer conductor surrounding and contacting the dielectric layer;
connecting the plug connector to the trimmed cable end to join the cable inner conductor with an inner conductor of the plug connector and the cable metallic corrugated outer conductor with an outer metallic conductor of the plug connector; and
cold forming a region of the HF corrugated coaxial cable attached to the plug connector or spaced from the plug connector by applying a bending force directed transversely to a longitudinal part of the HF corrugated coaxial cable and a tensile force directed longitudinally to the HF coaxial cable to form a permanent curved bend subtending an angle between 85° and 95° in the corrugated coaxial cable with a radius length rα extending from a center point to a curved bend of the HF corrugated coaxial cable which alters the line impedance Zk rk,min a maximum of less than 1 ohm when 0.2 rk,min≦rα≦0.9 rk,min.

2. The method according to claim 1, comprising:
coating at least the bend of the HF corrugated cable with a plastic or an adhesive.

3. The method according to claim 1, comprising:
forming the HF corrugated coaxial cable to join the angular plug connector to the cable end while the cable is releasably attached to a retainer, which is guided pivotably relatively to a bending guide to form a bend; and wherein
the retainer includes the angular plug connector joined to the HF corrugated cable which is pivoted relative to the bending guide, the HF corrugated coaxial cable is attached to or spaced from the plug connector and contacts the bending guide while an orthogonal bending force is applied to the bending guide and an axial force is applied to the HF coaxial corrugated cable longitudinally at a region spaced apart from the plug connection and the axial force creates tensile stress within the HF corrugated coaxial cable during the pivoting of the retainer.

4. The method according to claim 2, comprising:
forming the HF corrugated coaxial cable to join the angular plug connector to the cable end while the cable is releasably attached to a retainer, which is guided pivotably relatively to a bending guide to form a bend; and wherein
the retainer includes the angular plug connector joined to the HF corrugated cable which is pivoted relative to the bending guide, the HF corrugated coaxial cable is attached to or spaced from the plug connector and contacts the bending guide while an orthogonal bending force is applied to the bending guide and an axial force is applied to the HF coaxial corrugated cable longitudinally at a region spaced apart from the plug connection and the axial force creates tensile stress within the HF corrugated coaxial cable during the pivoting of the retainer.

5. The method according to claim 3, comprising:
applying the orthogonal force to the HF coaxial corrugated cable during pivoting of the retainer relative to the bending guide.

6. The method according to claim 4, comprising:
applying the orthogonal force to the HF coaxial corrugated cable during pivoting of the retainer relative to the bending guide.

7. The method according to claim 5, comprising:
applying the orthogonal force by guiding a rolling or sliding body relative to the bending guide which contacts the HF corrugated coaxial cable.

8. The method according to claim 3, comprising:
contacting the HF corrugated coaxial cable with the rolling or the sliding body with at least an eighth of a circumferential edge thereof.

9. The method according to claim 4, comprising:
contacting the HF corrugated coaxial cable with the rolling or the sliding body with at least an eighth of a circumferential edge thereof.

10. The method according to claim 1, comprising:
cold forming the HF corrugated coaxial cable which joins the straight plug connector to the cable end while the cable end is fixed to a stationary retainer.

11. The method according to claim 2, comprising:
cold forming the HF corrugated coaxial cable which joins the straight plug connector to the cable end while the cable end is fixed to a stationary retainer.

12. The method according to claim 1, comprising:
applying the bending force and the tensile stress during cold forming without altering an electrical diameter of the bend to vary more than 10% from an electrical diameter of a straight region of the HF corrugated coaxial cable.

13. The method according to claim 1, comprising:
bending the HF corrugated coaxial cable permanently to have a bending radius rα, where 0.4 rk,min≦rα≦0.6 rk,min, while the HF corrugated coaxial cable is attached to or is spaced from the plug connector.