US 2852752 A
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Description (OCR text may contain errors)
Sept. 6, 1958 R. L. MqcREARY 2,852,752
COUPLING MEANS Filed July 18. 1951 fiiyf INVENTOR.
- Rmrnl MCRumv BY A T Tokus v United States Patent COUPLING MEANS.
Ralph L. McCreary, Cedar Rapids, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa, a corporation of Iowa Application JulylS, 1951, Serial Noi 237,387 3 Claims. (cl. 333-33 This invention relates in general to. coupling means and in particular to apparatus. for coupling energy between a pair of wave guides while maintaining a vacuum seal between the wave guides. L
In electronics, it is oftentimes desirable to couple the high frequency energy from an evacuated envelope to a wave guide open to atmospheric pressure. For example, in' radar, it is oftentimes desirable to beam energy from an open wave guide toward atarget. The output Wave guide oftentimes receives its energy from. anevacuv ty v n by ahigh freq encytu It has b n customarypreviously to couple the output from the evacuated nant cavity by sealingoff h end of a wave guide: connected to the cavity with a dielectric ma t ri s h a slassorce arniawhich is bondedto the metallic parts. The seal thus formed is subjected to excessive heating due to the energy passing therethrough and with levels of energy now available with high power tubes, the dielectrics may be over heated and thus destroyed.
As the operating frequency is increased, the dimensions of the tube and the transmission lines are decreased. This means that a seal placed either in the tube or transmission line must occupy less volume at higher frequencies. For comparable power outputs the energy density at higher frequencies is therefore greater and a dielectric material therefore intercepts more energy per unit volume at these higher frequencies. Hence, for a given form of seal and type of dielectric material the power output of the tube must be decreased as the frequency is increased.
It is an object of this invention therefore to provide a means for coupling energy from an evacuated chamber to an open chamber or wave guide.
Another object of this invention is to provide coupling means for coupling energy from a first wave guide section to a second wave guide section while maintaining a pressure gradient between the two wave guides.
A feature of this invention is found in the provision for a plurality of openings formed longitudinally between adjacent wave guides with probes supported in each opening with a feather edge seal. 4
Further objects, features and advantages of this invention will become apparent from the following description and claims when read in view of the drawing, in which:
Figure 1 illustrates a pair of rectangular Wave guides with a coupling of this invention mounted between;
Figure 2 is a detailed view of one of the seals about a probe;
Figure 3 is a view illustrating coupling from a single wave guide to a pair of wave guides;
Figure 4 illustrates a modification of this invention for coupling energy between a pair of rectangular wave guides; and
Figure 5 illustrates a modification of this invention illustrating means for coupling enrgy between a circular wave guide and a coaxial line.
Figure 1 illustrates a wave guide which has its end 11 closed by a metal cover. The wave guide 10, for
' guides 10 and 14. As best shown in detail in Figure 2,
the top wall 12 and the bottom-wall 13 are formed with openings through which the probes 17 extend. The probes 17 are supported by glass discs 18 and a. ring 19 is formed with a feathered or thin edge 21 which: is embedded in the glass. The outer portion of the ring 19 is welded to the bottom wall 13 of wave guide 14.
The probes 17 extend into the confines of both wave guides and due to antenna action, transfer energy from one wave guide to the other.
As shown in Figure 1, a plurality of probes 17 may be used and the lengths may be varied so that each probe couples the same amount of energy. 7
There are two ways in which the energy coupled between wave guides may be controlled. One is by regulating the length of the probes and the other is by varying the positions of the probes relative to the center of the wave guides. If a probe extends essentially across the wave guide and is located in the center, it will form a short circuit which will remove substantially all of the energy traveling down the wave guide. However, if a large amount of energy is being transferred, one probe will be overloaded and a burn-out is likely to occur. For this reason, if it is assumed that energy is traveling down the wave guide 10 from the left to the right with reference to Figure 1, the probe 17 first intercepting the energy will be shorter than the. subsequent probes. This will allow the energy to be evenly distributed among the various probes without overloading any.
Alternatively, the distribution of energy may be con trolled by having the first probe close to one of the sides of the wave guide and each succeeding probe nearer the center.
A modification of this invention is shown in Figure 3 wherein the output of a first wave guide 22 which has its end 23 closed is coupled to a pair of wave guides 24 and 26 which have their respective ends 27 and 28 closed. A plurality of probes 17 couple energy from the wave guide 22 to the wave guides 24 and 26.
Figure-4 illustrates a further modification of this invention wherein the probes 17 are replaced by a conductive Wedge 29 supported between wave guides 31 and 32 by a glass to Kovar seal 30. The wedge 29 represents an infinite ntunber of probes placed very close together.
Figure 5 illustrates a means for coupling energy between a circular wave guide and a coaxial line. A circular wave guide 33 has its end 34 closed and an outer conductor 36 of a coaxial line is mounted concentric about the circular wave guide 33 and has its end 37 closed and sealed to the exterior of the circular wave guide 33. The coaxial line is formed by extending the circular wave guide past the closed end 34 so as to form the center conductor of the coaxial line and the outer conductor is continued about the center conductor.
A plurality of probes 17 are mounted in the wall of the circular wave guide 33 by a glass to Kovar seal as illustrated in Figure 2. Energy will be coupled from the circular wave guide to the coaxial line.
It is seen that this invention provides means for coupling energy between sealed and open wave guide sections. Applicant has discovered that the type of seal and coupling means disclosed herein are very eflicient and allow substantially all of the power to be coupled from one overloaded and there is no failure due to overheating.
Although this invention has been described with respect to particular embodiments thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention as defined by the appended claims,
1. Means for transferring substantial amounts of energy between adjacent wave guides where it is desired to maintain a pressure differential between the wave guides comprising, an input wave guide with one end closed, an output wave guide with one end closed, a common wall between an overlapping portion of said input and output wave guides near their ends and formed with a plurality of openings that are longitudinally spaced along said common wall, a plurality of thin flexible rings sealed to said common wall about each of said openings, a plurality of insulating discs fused into the openings of the plurality of rings, and a plurality of conducting probes of various lengths individually supported at their mid-points in the plurality of glass discs with their ends extending into adjoining wave guide sections.
2. Apparatus fortransferring energy between adjacent wave guides where it is desired to maintain a pressure differential between the wave guides comprising, a first wave guide with one end closed, a second wave guide with one end closed, a common wall between said wave guides near their closed ends and formed with a plurality of openings that are both longitudinally and laterally spaced from each other, a plurality of thin flexible rings welded to said common wall, a plurality of insulating discs fused into the openings of said rings, and a plurality of probes supported in said discs with opposite ends extending into the first and second wave guides.
3. Apparatus for transferring substantial amounts of energy between adjacent wave guides where it is desired to maintain a pressure difierential between the wave guides comprising, a first wave guide with one end closed, a second wave guide with one end closed, a common wall formed with a plurality of openings between the first and second wave guides, a plurality of insulatingdiscs supported in the openings, and a plurality of conducting probes of various lengths extending through said glass discs with opposite ends extending into said first and second wave guides, said first and second wave guides being concentrically mounted cylinders.
References Cited in the file of this patent UNITED STATES PATENTS 7 Riblet Feb. 14,