FR2644282A1 - SUPPORT SYSTEM FOR INSULATING MATERIAL IN A COAXIAL LINE - Google Patents

Abstract

An insulating material support system in a coaxial line comprises an insulating material support having a discode portion 1b and a region made as a socket 1a which surrounds an inner conductor segment 5a. In order to avoid field overcurrents in the region of the transition between the insulating material support and the inner conductor and in the surrounding region, it is proposed to realize the inner conductor parts 4, 5 located on both sides of the segment of inner conductor 5a surrounded by the sleeve 1a of the insulating material support in such a way that they partially cover the sleeve 1a of the insulating material support 1.

Description

i -The invention involves a support system in sioiate matter in, a

  coaxial line, comprising a support in insulating material aul is disposed between the inner conductor and the conductor. outside and whose central region, surrounding a segment of the inner conductor of reduced diameter. is made in the form of a socket where: the axial length is greater than the thickness of the disc part of the support made of insulating material, said see in the coaxial cavity, an annular slot in between the inner conductor segment reduced diameter and surface The inner envelope

cv'li dricue de la aouille.

  An insulating material support system of this kind is known from patent DE 20 20 173. Admittedly, this insulating material support system has good high frequency characteristics, that is to say that '' it produces only a slight degradation of the reflectance over the whole extent of a large bandwidth, but it is not satisfactory in that

  - design the resistance to voltage discharges.

  To improve resistance to voltage discharges, it is also already known to have on the inner conductor, the two sides of the part of a support made of insulating material which surrounds this conductor, the guard rings known in the high voltage technique , in the form of appropriate thickenings of the inner conductor, but the result is that the reflectance is increased considerably or at least cannot be kept at a low value acceptable within the limits of a width narrow strip. The reason for this is the capacitive effect of the guard rings, which cannot be fully

compensates for a wide band.

  The object of the invention is to provide a support system for insulating material of the kind defined in the preamble in such a way that the coaxial line which is drawn therefrom can be used over a wide band with a: reflection factor for the transmission of powers. HF very high, that is to say that the form of construction of the support system in insulating material gives a very high resistance to the discharges of

zens4on.

  -e object is achieved according to the invention by the fact that the inner conductor parts located of the two cokes of the inner conductor segment of diameter re-had partially cover the socket of the support in

insulating material.

  -at. this construction characteristic, field intensities in the region of the transition between the support in insulating material and the inner conductor and in the neighboring region are avoided or at least reduced to a large extent. At the same time, the extended current path along the inner conductor leads to a. broadband inductive compensation of the capacity represented by the support in

insulating material.

  Additional improvements in the resistance to discharge are obtained by the following additional arrangements: first, the annular segments of the parts of the inner conductor which cover the sleeve are rounded, at least at their end surfaces facing the support in insulating material; secondly, there is a slot between each of the end surfaces of the annular segments of the parts of the inner conductor which cover the socket and the socket of insulating material; thirdly, the transition between the discoidal part of the insulating material support and the central bushing thereof is rounded; fourthly, a slot is formed between the cylindrical inner envelope surfaces of the annular segments of the parts of the inner conductor which cover the sleeve and the cylindrical outer envelope surface of the sleeve of the insulating support; finally, the inner conductor has an outer diameter increases in the region of its annular segments which cover the socket. In addition to removing sharp edges throughout the transition region between the inner conductor and the insulating material support, the slots provided between the insulating material support region adjacent to the inner conductor and the neighboring edges of the inner conductor contribute to a reduction. uniform. field strengths. The form given to the device can be chosen without difficulty in such a way that a broadband compensation of the capacity formed by the support in insulating material is obtained by 2-5 increasing the inductivity of the inner conductor in the same plane radial or approximately in the

same radial plane.

  The insulating material support system according to the invention will be described below with reference to the appended figure which shows in a simplified manner a form of embodiment of the invention given as

example.

  Referring to the figure. the support system comprises a support made of insulating material 1 between two 3. contiguous parts of a coaxial line which consists of the outer conductor segments 2 and 3, as well as

  tubular inner conductor parts 4 and 5.

  The support made of insulating material i is essentially produced in the form of a disc lb, but it has, in its central region which surrounds an inner conductor segment 5a of reduced outside diameter, the shape of a socket la whose axial length a is more large than the thickness d of the discoidal part lb of the insulating material support 1 disposed in the coaxial cavity 6. Between the inner conductor segment 5a of reduced outer diameter and the cylindrical inner envelope surface of the socket la of the support insulating material 1, there is an annular slot 7 for the reduction of the strong field strengths therein

  otherwise occur at the boundary surfaces.

  The inner conductor parts 4, 5 located on the two sides of the inner conductor segment 5a partially cover the socket 1a of the support made of insulating material 1. In other words, the socket 1a of the support made of insulating material 1, which can be also called support leg, is received in an undercut delimited by the two inner conductor parts 4, 5. The annular segments 4b and 5b of the inner conductor parts 4, 5 which cover the socket are rounded, at least at least level of their end surfaces 4b 'and 5b' directed towards the support in

insulating material 1.

  Between each of the end surfaces 4b 'and 5b' of the annular segments 4b, 5b covering the sleeve 1a, a slot s is formed which gradually widens from the inside towards the outside, due to a part of the radii of the annular segments 4b, 5b and on the other hand of the rounding of the transition between the discoidal part 1b of the support made of insulating material 1 and the sleeve 1a. This gradual widening of the slit makes, for an appropriate dimensioning, a non-negligible contribution to a uniform reduction of the field strengths which occur in this region. The two slots s continue in slots if between the cylindrical inner casing surfaces of the annular segments 4b, 5b of the inner conductor parts 4, 5 which cover the bushing la and the cylindrical outer casing surface of the bushing la of the support in insulating material 1. The slots if O10 also serve to avoid the action of constraining forces

on the socket.

  In the embodiment shown, the inner conductor parts 4, 5 have, in the region of their annular segments 4b, 5b which cover the bushing la, an outer diameter Di which is larger than the nominal outer diameter D of the inner conductor . This thickening of the inner conductor in the region of the annular segments 4b, 5b acts capacitively and thus compensates, for appropriate dimensioning, the inductive component produced by the inner conductor segment 5a of

reduced diameter.

DREAM NDICATI OENTS

  - Support system in insulating material in a coaxial Linhe, comprising a support in king-ante material yes is disposed between the inner conductor e The outer conductor and whose central region, surrounding a segment to the inner conductor of diameter sated: Z, is rea: isee in the form of a socket whose axial sling is greater than the thickness of the disc ar_-ie of the support made of insulating material disposed in the coaxial cavity, an annular slot 1O being formed between the inner conductor segment -d diameter reduced and the cylindrical inner envelope surface of the sleeve, characterized in that the inner conductor parts (4, 5) located on the two dimensions of the inner conductor segment <(Sa) of d: reduced anchor partially cover the sleeve (the) of

support in insulating material (1).

  2.- System according to claim 1, characterized in that the annular segments (4b, 5b) of the parts of the inner conductor (4, 5) which cover the sleeve (la) are rounded, at least at their surfaces of end (4b ', 5b') directed towards the support in

insulating material (1).

  3.- System - according to claim 1 or 2, characterized in that Q-u'a slot (s) is formed between each of the end surfaces (4b ', 5b') of the annular segments (4b, 5b) of the parts of the inner conductor which covers the sleeve (la) and the material sleeve

insulating (1).

  4.- System according to any one of the claims

  1 & 3. characterized in that the transition between the discoid part (lb) of the insulating material support (1) and the central sleeve (la) of this is rounded.

  5.- System according to any one of the claims

  1 & 4, characterized in that a slot (si) is formed between the cylindrical inner envelope surfaces of the annular segments (4b, 5b) of the parts of the inner conductor 14, 5) which cover the socket (la) and the cylindrical outer shell surface of

  the sleeve (la) of the insulating material support.

  5.- System according to any one of the claims

  1 to 5, characterized in that the inner conductor has an increased outer diameter (Di) in the region of its annular segments (4b, 5b) which cover the socket.