Waveguide absorber

A waveguide absorber which withstands high mechanical and thermal loads is typified in that a member (4) exhibiting absorber material is clamped between waveguide walls (5, 6) in such a way that at least one wall region (5) adjoining the member (4) is constructed flexibly, and that a force acting on the flexible wall region (5) presses the latter against the member (4).

BACKGROUND OF THE INVENTION 
The present invention relates to a waveguide absorber which has at least 
one member inserted into a waveguide and exhibiting absorber material. 
Terminating impedances and attenuators are frequently required in microwave 
technology. Use is made as such of waveguide absorbers such as are 
disclosed, for example, in the "Taschenbuch der Hochfrequenztechnik" 
["Manual of radio-frequency technology"], H. Meinke and F. W. Gundlach, 
3rd edition, 1968, pages 443 to 445. This publication does not reveal the 
means by which the members consisting of absorber material and arranged in 
the waveguide are fixed. 
Special requirements for fixing the absorbing member are to be made for the 
application of waveguide absorbers in the field of space flight. The 
fixing is to be able to withstand high mechanical and thermal loads. It is 
the object of the present invention to specify a waveguide absorber of the 
type mentioned at the beginning which fulfils the abovementioned 
requirements. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a 
waveguide absorber which eliminates the disadvantages of the prior art. 
In keeping with these objects and with others which will become apparent 
hereinafter, one feature of the present invention resides, briefly stated, 
in a waveguide absorber which has at least one member inserted into a 
waveguide and composed at least partially of absorber material, wherein 
the member is clamped between opposing waveguide walls by providing that 
at least one wall region resting on the member is constructed flexibly, 
and that a force acting on the flexible wall region presses the latter 
against the member and the flexible wall region is realized by a strong 
reduction of wall thickness of one of said waveguide walls in the wall 
region resting on the member as compared with the opposing, rigid, 
waveguide wall. 
In accordance with another advantageous feature of the flexible wall region 
is realized by an appropriately strong reduction in the wall thickness. 
In accordance with still another feature of the present invention, a 
pressure clamp exerts the clamping pressure on the flexible wall region, 
rests on the flexible wall region and is screwed to a wall region of the 
waveguide which is opposite the flexible wall region. The clamping 
pressure is produced by a correspondingly tight screwing of the pressure 
clamp to the opposite wall region. 
Finally, the pressure lamp can be formed as screws which can be screwed 
against the flexible wall region in order to be able to produce the 
clamping pressure. 
The invention has the advantage that no use is made for fixing the absorber 
member of the usual materials such as adhesive or solder, which often do 
not withstand very high thermal or mechanical stress. In addition, the 
mechanical outlay is very low in the waveguide absorber according to the 
invention. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT 
The FIGURE shows a side view of a rectangular waveguide 1 which is provided 
at one end with a flange 2, and whose other end is sealed by a cover 3. 
Inserted into this waveguide 1 is a member 4 which consists at least 
partially of a thermostable absorber material (for example, silicon 
carbide). The member 4 extends with a subregion over the entire height of 
the waveguide and has the shape of a wedge. The absorber member can have 
any arbitrarily different shape; it depends, for example, on the 
electrical requirements and on the mounting position in the waveguide. It 
is important that the member extends at least partially over the entire 
height of the waveguide (or the entire diameter of the waveguide in the 
case of a round waveguide), so that it can be clamped between mutually 
opposite wall regions of the waveguide. 
In order to fix the member 4 in the waveguide 1 by clamping, the thickness 
of one waveguide wall 5 is so strongly reduced at least in the region 
resting on the member 4 that this region is flexible. If a pressure is 
exerted on this flexible wall region 5, the member 4 is pressed against 
the opposite rigid waveguide wall 6. The result is a contact, which 
conducts heat well, between the member 4 and this waveguide wall 6 on 
whose outside a cooling system, for example a heat pipe, is arranged in 
accordance with the illustrated exemplary embodiment. 
A pressure clamp 8 lying on the flexible wall region 5 is fastened by means 
of screws 9 to the opposite waveguide wall 6. By means of these fastening 
screws 9 themselves, either the pressure clamp 8 can be tensioned so far 
that it exerts the required clamping pressure on the flexible wall region 
5, or it is possible apart from the fastening screws 9 to provide in 
addition in the pressure clamp 8 screws which can be screwed against the 
flexible wall region 5.