DE2445565A1 - HIGH FREQUENCY COAXIAL CABLE AND METHOD OF ITS MANUFACTURE - Google Patents

Description

PATENT ADVOCATES A. GRÜNECKER

DIPL.-INQ.

* H. KINKELDEY

DR.-IN3.

W. STOCKMAIR

ΟΛΛ5565 DR-INa. -AeB (CALTBCH)

AtHOOWvJ _{K SCHUMANN}

. DR. RER. NAT. · OtPU-PHVS.

P. H. JAKOB

DIPL.-INQ.

P 8568-32 / Sr g. bezold

= = = = == = = 3 === - DR.RER. NAT. · DIPL.-CHEM.

MUNICH

E. K. WEIL

DR. RKR. OEC. INQ.

LINDAU

8 MUNICH 22

MAXIMILIANSTRASSa 43

September 19, 1974

Bunker Ramo Corporation

900 Commerce Drive

Oak Brook, 111. 60521. USA

High frequency coaxial cable and method of - its manufacture.

The invention relates to a high frequency coaxial cable and to a method for its manufacture which has a low Should have reflection factor and low insertion losses.

When transmitting high frequency signals, especially in Gigahertz range, the structure of the transmission cables is particularly critical. In addition, such cables are often Bends and other physical influences that affect the physical arrangement of the individual components make it even more critical.

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There are therefore transmission links with low insertion losses and a low reflection factor within a label that provides a constant Reflection factor and insertion loss also at Bends and other mechanical stresses

One of the problems with constructing such a coaxial cable is achieving the required high electrical power (Tolerances. This is the case, for example, with the manufacture of a coaxial cable with a characteristic impedance of 50 ohms _ + 1 ohms often difficult to get the ladder and the to change electrical parts so that an impedance in this range is achieved.

The object of the invention is to provide a new high-frequency coaxial cable and a method for its production, which allows a relatively simple adjustment of its components to the desired impedance properties within to be able to maintain close tolerances.

In the case of a high-frequency coaxial cable of the type mentioned, this object is achieved by an outer conductor with a spacing arranged inner turns, which form inner surfaces, by at least one inner conductor which is axially within the Outer conductor is arranged by a dielectric part comprising the inner conductor with a plurality of axially aligned Arms that extend towards the outer conductor and through at least one inwardly extending ratchet tooth, which extends along the inner surfaces of the outer conductor at a distance and against the arms of the dielectric Partly pushes to lock this in a desired position, the radial position of the ratchet tooth accordingly the desired electrical properties of the cable is selected for their adjustment.

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In the high-frequency coaxial cable according to the invention So during its manufacture routine tests were carried out and a ratchet was slightly modified to adjust the impedance correct within a desired range. Such a ratchet or projection can easily be inserted into the individual links of a corrugated outer conductor are pressed in before the assembly of the cable or else a Cable that has already been assembled without its shielding wire mesh and outer plastic sheath can continue are compressed to give the desired impedance properties to reach.

The new high-frequency coaxial cable therefore has a corrugated shape Outer conductors with spaced inner turns that form flat inner surfaces. Within the Outer conductor is axially arranged an inner conductor around which a dielectric core is formed, the axially aligned Has arms that extend towards the outer conductor. Inwardly extending ratchet teeth or projections, .the spaced along the flat inner surfaces of the outer conductor press against the arms of the dielectric Core to hold or lock it in the desired position and thus the smallest inner diameter of the Form outer conductor.

According to an essential development of the invention, a method for producing the new high-frequency coaxial cable is provided specified, which is characterized by the fact that an outer conductor with spaced inner turns, form the inner surfaces, is produced that a dielectric core is formed around an inner conductor, which has several axially aligned arms that the inner

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head and the core is inserted axially into the outer conductor and that at least one inwardly extending Ratchet tooth is formed, which is spaced along the inner surfaces of the outer conductor to form a smallest inner diameter of the outer conductor runs.

The invention is illustrated by means of one in the drawing Embodiment explained in more detail. Show in detail:

Pig. 1 shows a partially sectioned representation of the new high-frequency coaxial cable,

Fig. 2 is a longitudinal sectional view of the coaxial cable the line 2-2 of Fig. 1, and

J shows an enlarged illustration of part of the cable, which is cut out along the line 3-3 in FIG.

Fig. 1 shows the new high-frequency coaxial cable, which has a selected outer conductor 10 with connecting or locking parts 11 and 12 inner turns. The inner turns 12 have substantially flat inner surfaces, which can be seen better in FIG. 3. Along each of the inner surfaces an inwardly extending projection or ratchet 13 is provided, the meaning of which will be explained later will. The locking parts 11 of the outer conductor 10 are connected to one another with the aid of soldering points 14. the The inner surface of the outer conductor is coated with a highly conductive metal such as silver or gold. Part A in Fig. essentially shows where the inner surfaces e.g. with silver

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2U5565

■ are coated or plated. For additional flexural rigidity To achieve a protective braid 15 made of wire and an outer sheath 16 made of plastic is provided, which surround the outer conductor 10.

The inner conductor 20 is coaxial within the outer conductor 10 arranged. A dielectric part or core 21 is cast around the inner conductor 20 and has arms 22, 23 and 24 which extend radially outward from the inner conductor and press against the outer conductor 10. The dielectric rise Core 21 is preferably made of polytetrafluoroethylene, although other dielectric materials can be used. The space 25 'that of that dielectric core 21 is occupied, is filled with air, which also acts as a dielectric material.

A key feature of the new high-frequency coaxial cable is the ratchet or projection 13 »on the flat inner surface 12 of the outer conductor 10 is arranged at a distance. By changing or choosing yourself inward extending projection or the radial position of the locking tooth 13 can be the effective inner diameter of the outer conductor 10 changed and thereby changed the impedance or electrical properties of the coaxial cable or accordingly can be set.

The outer conductor 10 forms a continuous path for the high frequency signals. The inner conductor 20 is preferably a silver coated twisted conductor, although a solid conductor can also be used if this is desired. The air-polytetrafluoroethylene arrangement reduces the dielectric constant and thus also the

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dielectric losses of the cable.

for best results, the diameter should be of the outer conductor 10 must be constant and the width of the turns must be equal to each other. The dielectric core 21 is connected to the outer conductor 10 by mechanical pressure. This makes the core and its inner conductor 20 held against a relative movement with respect to the outer conductor 10. This' becomes an excellent mutual Alignment achieved even if the cable is subjected to bending or mechanical shock.

The impedance of the cable is adjusted by the amount of compression of the outer diameter. The impedance of the coaxial cable can be calculated from the following expression:

Z - 128 log _{10 t}

in the DM the main diameter of the inner diameter of the outer conductor, ID the outer diameter of the inner conductor and E are the effective dielectric constant of the core assembly.

The insertion loss of the cable is the sum of the inner conductor losses, the dielectric losses and the External conductor losses calculated. The inner conductor losses and dielectric loss becomes more conventional by using it Microwave relationships calculated for the insertion losses. The outer conductor losses are from conventional Expressing determined with the exception that the added link length due to the turns in this

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Calculations need to be introduced. The cable has a low reflection factor and high electrical phase stability with mechanical stress and a high consistency in phase maintenance. For example of the low insertion loss, measurements of less than 0.35 db per 0.3 m of cable length. at 16 GHz, less than 0.14 db per 0.3 m cable length at 8 GHz and less than 0.065 db per 0.3 m cable length at 2 GHz for a Transmission path recorded with 50 ohms.

When manufacturing the new high-frequency coaxial cable, the ratchet or protrusion in the outer conductor can be in front of the Joining the cable together must be shaped in order to achieve the calculated values. At one in a manufacturing process Once the high-frequency coaxial cable has been assembled, the selected outer conductor is formed with inner turns, representing flat inner surfaces, then a dielectric core is formed around an inner conductor, the dielectric core has several axially aligned arms, the inner conductor becomes axial together with the dielectric core arranged within the outer conductor and then several inwardly extending projections or Ratchet teeth pressed in along the flat inner surfaces of the outer conductor to the minimum inner diameter of the outer conductor to build.

The projections or ratchet teeth can be used during the production of the outer conductor or after the assembly of the inner conductor, Outer conductor and dielectric core can be produced or changed. In this way, after the Assembling these three components the impedance of the cable is measured and the depth of the ratchet can be changed

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in order to also change the impedance in the desired range. The cable is then enveloped by the wire mesh and the plastic jacket. Becomes the inner surface of the outer conductor plated with silver, this step is preferably performed prior to assembling the inner conductor, outer conductor and of the dielectric core.

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Claims (13)

Claims 1. High-frequency coaxial cable, marked chnet u r c h an outer conductor (10) with spaced apart inner turns (12), which form inner surfaces, through at least one inner conductor (20), which is axially inside of the outer conductor is arranged by a dielectric part (21) comprising a plurality of the inner conductor axially aligned arms' (22) extending towards the outer conductor and through at least one inwardly extending Ratchet tooth (13) which extends along the inner surfaces of the outer conductor at a distance and against the arms of the dielectric member to lock it in a desired position, the radial position of the Ratchet tooth is selected according to the desired electrical properties of the cable for their adjustment. 2. High-frequency coaxial cable according to claim 1, characterized characterized in that the outer conductor (10) wt It is and that the ratchet tooth (13) extends around the circumference around and axially along the face of the outer conductor. 3. high frequency ^ coaxial cable according to claim 1 or 2, characterized in that the inner conductor (20) has a plurality of coated with silver has twisted wires. 4. High-frequency coaxial cable according to one of claims 1-3 » characterized in that the outer conductor (10) interlocked parts (11) and its inner surface is plated with silver. 5098 15/090 1 ■ * IvJ "~ 5. High-frequency coaxial cable according to claim 4, characterized in that the outer conductor (10) soldered to its interlocked parts (11). (14) is. 6. High-frequency coaxial cable according to one of claims 1-5 » characterized in that the outer conductor (10) is enclosed by a wire mesh (15) and a plastic outer jacket (16). 7. High-frequency coaxial cable according to one of claims 1-6, characterized in that the dielectric part (21) is attached to the inner conductor (20) is. 8. High-frequency coaxial cable according to one of claims 4-7 » characterized in that the outer conductor (1O) consists of a series of continuous turns (12) with interlocked opposing edges (11) and a wall portion within each turn (12) between the opposite edges is formed, which is bent radially inwardly from the opposite edges, wherein the ratchet tooth (13) is formed in this wall part, around the radially outwardly extending ends of a to act on each of the arms (22). 9. A method for producing a high-frequency coaxial cable, in particular according to one of claims 1-8, characterized characterized in that an outer conductor with spaced inner turns, the inner surfaces form, is produced that around an inner conductor 50981 5/0901 dielectric core is formed, the several axially aligned Has arms that the inner conductor and the core is inserted axially into the outer conductor and that at least one inwardly extending ratchet tooth is formed, which is spaced along the inner surfaces of the outer conductor to Formation of a smallest inner diameter of the outer conductor runs. 10. The method according to claim 9 »characterized in that that the inner surface of the outer conductor is plated with silver. 11. The method according to claim 9 or 10, characterized characterized in that the corrugated outer conductor is formed with interlocking parts that are soldered together. 12. The method according to any one of claims 9-11 »characterized ichnet that the outer conductor of a Wire mesh and enclosed in a plastic outer sheath will. 13. The method according to any one of claims 9-12, characterized characterized in that the projection of a plurality of ratchet teeth after assembly of the inner conductor, of the outer conductor and the dielectric core is changed in order to keep the impedance within a desired tolerance range to change. 509815/0901 rs ¹ page