Coupling device for a coaxial line system

A coupling device for two coaxial line systems which extend in planes disposed above one another. The coupling device comprises a pin, and a sleeve which is pushed over the pin in a no-contact manner, and between the interior conductors permits a high-frequency energy transmission.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to a coupling device for a coaxial conductor system 
of the type in which conductor sections are formed in a planar member 
which defines external conductors with a rectilinear (generally, square or 
rectangular) cross-section in which, by means of dielectric supporting 
material, interior conductors are disposed which have a rectangular 
cross-section. 
German Patent Document DE-PS 27 01 228, discloses a coaxial conductor 
system of the type referred to herein, which comprises exterior conductor 
sections of a square or rectangular cross-section embedded in a base plate 
in which a rectangular interior conductor is disposed by means of 
dielectric supporting material. The base plate is closed off by a planar 
covering plate. However, the subject patent reference fails to disclose 
any special embodiment of a coupling device suitable for use with such a 
coaxial conductor system. 
Heretofore, it has been customary to construct coaxial coupling devices 
with parts which are rigidly screwed together. However, this system has 
the disadvantage that it is severely stressed mechanically by thermal 
expansion. Another embodiment with elastic plug contacts has the 
disadvantage of generating passive intermodulation products. 
It is therefore an object of the present invention to provide a coupling 
device for coaxial conductor systems of this type (particularly for the 
coupling of two conductor sections arranged in planes disposed above one 
another) which is characterized by low losses and can also compensate for 
temperature-caused differences. 
This object is achieved according to the invention, by means of a coupling 
comprising a pin mounted on the interior conductor of the first coaxial 
conductor which is inserted into a sleeve mounted on the interior 
conductor of the second coaxial conductor. The pin and sleeve extend 
through a coupling opening in a common wall shared by the exterior 
conductors of the respective coaxial conductors. 
A particular advantage of the coupling device according to the invention is 
that the above-mentioned disadvantages of the prior art coupling devices 
are eliminated and that the compensation of different linear expansions 
because of a temperature gradient between interior and exterior conductors 
or due to different coefficients of expansion of the materials is 
possible. 
Other objects, advantages and novel features of the present invention will 
become apparent from the following detailed description of the invention 
when considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS 
The coupling device is used to transmit high frequency electromagnetic 
energy from a first coaxial conductor 1 of the type referred to above, 
into a second coaxial conductor 2 arranged below it. The exterior wall of 
the first coaxial conductor 1 is formed by a recess in a housing 13 which 
is covered by a plate 3. In the same manner, the second coaxial conductor 
2 is embedded in the housing 14. In the common wall formed by the plate 3, 
a coupling opening 4 is provided. The vertical distance between the 
central axis 16 of the coupling opening 4 and the short circuits 6, 9 of 
the respective coaxial conductors 1, 2 is approximately half the 
transverse dimension of the respective coaxial conductors 1, 2. The 
interior conductors 5, 7 of the coaxial conductors 1, 2 extend slightly 
beyond the center of the coupling opening 4 in the direction of the 
respective short circuits 6, 9 terminating the respective coaxial 
conductors. In this case, the short circuits may be constructed as a plane 
or as a curved wall. 
At the point where the central axis 16 of the coupling opening 4 passes 
through interior conductor 5 of the first coaxial conductor 1, a pin 8 is 
mechanically fastened to the interior conductor 5, which pin extends 
through the coupling opening 4 and into an opening in the interior 
conductor 7 of the second coaxial conductor 2. In a no-contact manner, a 
sleeve 10 surrounds pin 8 and is fastened to the interior conductor 7 of 
the second coaxial conductor 2. As can be seen from the FIGURE, pin 8 is 
slidably inserted into sleeve 10, and provides the coupling between the 
respective coaxial conductors 1 and 2; it can be withdrawn (upwardly in 
the FIGURE) to break the coupling and separate the coaxial conductors. 
Between the pin 8 and the sleeve 10, a narrow air gap 15 is provided which 
is used to compensate for different temperature-caused linear expansions. 
Advantageously, the pin 8 is covered with a thin insulator made of, for 
example, the synthetic material known under the trademark name Teflon. The 
sleeve 10 extends from the interior conductor 7 of the second coaxial 
conductor 2 to close to the interior conductor 5 of the first coaxial 
conductor 1 without, however, coming in contact with it. 
The design of the coupling device according to the invention may be 
optimized in a number of ways in order to adapt it to a particular 
environment. For example, the diameter of the coupling opening 4 can be 
varied relative to the outside diameter of the sleeve 10. Also, the pin 8 
and the sleeve 10 may be guided through the interior conductor 7 of the 
second coaxial conductor 2 and may extend a distance beyond it as shown in 
the FIGURE. In the area of the short circuit 9, steps 12 may be provided 
in the exterior wall; and finally, the width of the rectangular interior 
conductor 5 and/or 7 may be decreased or increased in the area of the 
coupling device 8, 10. 
Although the invention has been described and illustrated in detail, it is 
to be clearly understood that the same is by way of illustration and 
example, and is not to be taken by way of limitation. The spirit and scope 
of the present invention are to be limited only by the terms of the 
appended claims.