EP3832791B1

EP3832791B1 - Power divider

Info

Publication number: EP3832791B1
Application number: EP19212846.0A
Authority: EP
Inventors: Andreas Schinagl-Weiß; Michael Schneider
Original assignee: Airbus Defence and Space GmbH; Airbus Defence and Space SAS
Current assignee: Airbus Defence and Space GmbH; Airbus Defence and Space SAS
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2023-11-15
Anticipated expiration: 2039-12-02
Also published as: EP3832791A1

Description

In the following, a waveguide power divider is disclosed.
A general problem, e.g. in the technical field of array antenna technology, is a limited space for a waveguide network behind the radiator because of the array density. For example, if implementing a diamond-shaped array grid for a multiple feed per beam concept with groups of four Horns, not a uniform power distribution is needed but a pair wise power distribution with unequal power between two pairs. Regarding this, the network gets more complex, even so the space is limited.
Waveguide arrangements for splitting electromagnetic energy provided are known e.g. from documents EP 0075394 A1 , EP 2869396 A1 , US 2015/0372369 A1 and ES 255634 . However, the waveguide arrangements disclosed by these documents provide an equal split of electromagnetic waves provided with regard to a magnitude of the waves provided. As set out above e.g. diamond-shaped array grids may require an unequal power split due to their array formation.
Further, document EP 1492191 B1 discloses a more flexible waveguide arrangement. However, this arrangement requires several movable components and requires, therefore, extensive space, which may not be available for a waveguide network behind the radiator. Additionally, since the disclosed arrangement comprises a plurality of movable components, failure susceptibility is increased compared to fixed waveguide arrangements.
The document US 2 941 166 A discloses a waveguide arrangement comprising a cuboid-shaped waveguide coupled to a plurality of output waveguides and an input waveguide coupled to the cuboid-shaped waveguide. In this connection, a propagation direction of an electromagnetic wave guided through the input waveguide is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides. The disclosed waveguide arrangement is configured to split an electromagnetic wave provided into the cuboid-shaped input waveguide into a plurality of electromagnetic waves guided through the output waveguides.
Another waveguide arrangement for splitting electromagnetic energy provided is disclosed by ISAO OHTA: "A New Six-Port Microwave Network: Six-Port Magic Junction", I.E.E.E. TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, 1 May 1988, pages 859-864.
Therefore, there is still a need for a compact enhanced power divider comprising an error unsusceptible layout and less movable parts, capable of an asymmetric split of an electromagnetic wave provided.
A solution for this problem is provided by an arrangement according to independent claims 1,8. Further embodiments are defined by the dependent claims.
A waveguide arrangement comprises a cuboid-shaped waveguide coupled to a plurality of output waveguides. The waveguide arrangement further comprises an input waveguide coupled to the cuboid-shaped waveguide. A propagation direction of an electromagnetic wave guided through the input waveguide is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides.
The waveguide arrangement is configured to split an electromagnetic wave provided into the input waveguide into a plurality of electromagnetic waves guided through the output waveguides. A power ratio of/between the plurality of electromagnetic waves travelling/propagating through the output waveguides is defined by an angle, α, enclosed by a polarization (or an imaginary two-dimensional plane extending along the polarization and/or indicated/defined by the polarization direction) of the wave guided by the input waveguide and a surface (or an imaginary two-dimensional plane extending along the surface and/or indicated/defined by the surface) of the cuboid-shaped waveguide on which an output waveguide is arranged.
With this proposed arrangement the magnitude of the power division between multiple output waveguides /ports can be determined by rotating a polarization direction of an electromagnetic wave provided with respect to the cuboid-shaped waveguide and/or the output waveguide arranged at the cuboid-shaped waveguide.
An advantage of the proposed arrangement is a very compact and reliable design suitable for limited space environments. Further, the arrangement is capable of covering a wide bandwidth independent of a desired coupling factor.
The waveguide arrangement may comprise two or four or more than four output waveguides. The output waveguides may be coupled with the cuboid-shaped waveguide. However, a propagation direction of waves guided through the output waveguides is always at least substantially perpendicular to a propagation direction of a wave propagating through and/or guided by the input-waveguide.
In some implementations, more than one output waveguide may be arranged/coupled to a surface of the cuboid-shaped waveguide.
The term "coupled" may be understood to mean that an output waveguide and/or the input waveguide is positioned on/at a surface/side of the cuboid-shaped waveguide, wherein the cuboid-shaped waveguide's surface/side comprises an opening enabling an unobstructed propagation of a guided electromagnetic wave from or to the output waveguide and/or the input waveguide through the opening. Thereby, the opening corresponds to the geometry of the output waveguide and/or the input waveguide and/or is covered/enclosed by the output waveguide and/or the input waveguide.
The term "power ratio of the plurality of electromagnetic waves" may define a power or magnitude ratio between the plurality of the electromagnetic waves guided (or traveling/propagating) through the plurality of output waveguides and/or a power or magnitude ratio between a certain electromagnetic wave guided (or traveling/propagating) through one of the plurality of output waveguides and a certain electromagnetic wave guided or provided (or traveling/propagating) through the input waveguide.
Further, at least two output waveguides of the plurality of output waveguides may be arranged at surfaces of the cuboid-shaped waveguide which oppose each other. In one implementation of the waveguide arrangement each of the output waveguides of the plurality of output waveguides opposes another of the output waveguides coupled with the cuboid-shaped waveguide.
In a variant of the waveguide arrangement one or two or four or all of the output waveguides are cuboid shaped or cylindrical-shaped waveguide terminals.
Further, one or two or four or all of the output waveguides may be identically-shaped output waveguides, particularly identically shaped cuboid shaped or cylindrical-shaped output waveguides.
An advantage of identically-shaped output waveguides is that no waveguide transitions are needed and, therefore, no phase issue arises.
The input waveguide can be implemented as cuboid-shaped waveguide or as cylindrical-shaped waveguide.
A geometric center of the input waveguide may be positioned, in a direction identical to a propagation direction of an electromagnetic wave traveling/propagating through the input waveguide, over a geometric center of the cuboid-shaped waveguide. In other words, the geometric center of the input waveguide may be positioned, seen from a two-dimensional top- or side-view of the arrangement in which the cuboid-shaped waveguide is seen as a rectangular surface, over a geometric center of the cuboid-shaped waveguide.
In case the input waveguide is implemented as cuboid-shaped waveguide, the polarization direction of the electromagnetic wave travelling through the input waveguide can be determined by the shape of the input waveguide and/or the polarization direction of the electromagnetic wave travelling through the input waveguide can be perpendicular and/or parallel to an inner wall of the waveguide. In other words, the implementation as a cuboid-shaped input waveguide allows to force and/or to steady the polarization direction of an electromagnetic wave to a desired polarization direction.
In consequence, if a cuboid-shaped input waveguide is implemented, the angle α can be alternatively defined as the angle enclosed by an inner surface of the cuboid-shaped input waveguide (or an imaginary two-dimensional plane along the inner surface and/or indicated/defined by the inner surface of input waveguide) and a surface of the cuboid-shaped waveguide (or an imaginary two-dimensional plane along the surface and/or indicated/defined by the surface of the cuboid-shaped waveguide).
The input waveguide can be coupled rotatably with the cuboid-shaped waveguide. In other words, the input waveguide may be rotated relative to the cuboid-shaped waveguide around an axis extending in the propagation direction of a wave propagating in or guided by the input waveguide.
An advantage of an input waveguide rotatably coupled to a waveguide, particularly a rotable cuboid-shaped waveguide, is that a power ratio between the electromagnetic waves provided or guided by the output waveguides can be adjusted e.g. to meet certain requirements of a concrete implementation. In other words, an advantage of a rotatably coupled cuboid-shaped input waveguide is that a polarization direction of the electromagnetic wave travelling/propagating through the input waveguide can be determined/changed by rotating the input waveguide relative to the cuboid-shaped waveguide. However, the waveguide arrangement design remains delicately compact, reliable and efficient compared to known arrangements since the number of movable parts/elements is reduced to a single one.
In a specific implementation the waveguide arrangement comprises four output waveguides each coupled to the cuboid-shaped waveguide, wherein each of the four output waveguides opposes another of the output waveguides coupled to the cuboid-shaped waveguide. In this implementation a power of an electromagnetic wave travelling in one of the output waveguides is defined by the factor "0.5 cos (a)" or "0.5 sin (a)", respectively, multiplicated with the power of the electromagnetic wave provided into the input waveguide.
Implementations of input waveguides and/or output waveguides comprising quadratic or ellipsoid cross-sectional shapes are explicitly possible.
The cuboid-shaped waveguide and/or the input waveguide and/or the output waveguides may comprise a metal material and/or may be made of a metal material.
An alternative waveguide arrangement, which provides an alternative solution for the problem defined above, comprises a cylindrical-shaped waveguide coupled to a plurality of output waveguides. An input waveguide is coupled to the cylindrical-shaped waveguide. A propagation direction of an electromagnetic wave guided through the input waveguide is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides.
The waveguide arrangement is configured to split an electromagnetic wave provided into the input waveguide into a plurality of electromagnetic waves guided through the output waveguides. A power ratio of/between the plurality of electromagnetic waves travelling through the output waveguides is defined by a polarization direction of the wave guided by the input waveguide, wherein the polarization direction of the electromagnetic wave travelling through the input waveguide is determined by a shape of the input waveguide.
The input waveguide can be coupled rotatably to the cylindrical-shaped waveguide. The input waveguide can be implemented as a cuboid-shaped waveguide.
An advantage of a rotatably coupled cuboid-shaped input waveguide is that a polarization direction of the electromagnetic wave travelling/propagating through the input waveguide can be determined/changed by rotating the input waveguide relative to the cylindrical-shaped waveguide.
Optionally, the waveguide arrangement comprises four output waveguides. Each of the output waveguides of the plurality of output waveguides can be arranged opposing another of the output waveguides coupled with the cylindrical-shaped waveguide.
To enhance the understanding of the arrangement described above the following figures are provided:

Figure 1: shows a perspective view of an example implementation of a waveguide arrangement.
Figure 2: shows a two-dimensional top view of the example implementation shown in figure 1.
Figure 3: shows an example course of a power ratio provided by an output waveguide in dependency of an angle a, wherein the relative magnitude values (0.5 to 0) relate to a magnitude value of an electromagnetic wave provided to the input waveguide.
Figure 4: shows a perspective view of another example implementation of a waveguide arrangement.
Figure 5: shows a two-dimensional top view of the example implementation shown in figure 4.
Figure 6: shows examples for cross-sectional designs of the input waveguide and output waveguides.
Figure 7: shows a perspective view of another example implementation of a waveguide arrangement.

If not explicitly described to the contrary, identical reference signs used in the drawings describe corresponding or similar components used for the different implementations. Further, to enhance clarity of the implementations shown, not all figures comprise reference signs for all elements shown.
Figure 1 shows a waveguide arrangement 100, which comprises a cuboid-shaped waveguide coupled to a plurality of output waveguides, particularly four output waveguides, each defining a Port to provide electromagnetic wave energy. An also cuboid-shaped input waveguide is coupled to a top-surface of the cuboid-shaped waveguide.
As shown in the figure, a propagation direction of an electromagnetic wave guided through the input waveguide is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides. In other words, the input waveguide extends orthogonal to each of shown the output waveguides.
The shown waveguide arrangement 100 is capable of splitting an electromagnetic wave provided into the input waveguide into a plurality, particularly four, of electromagnetic waves guided and/or propagating through the output waveguides.
The power ratio of the electromagnetic waves travelling/propagating through the output waveguides to the Ports is defined by an angle, a, enclosed by a polarization direction of the wave guided by (or travelling/propagating through) the input waveguide and a (lateral) surface of the cuboid-shaped waveguide on which an output waveguide is arranged.
Since, as shown in the figure, the input waveguide is a cuboid-shaped input waveguide, the angle α is also to be defined as an angle enclosed by an inner wall of the input waveguide and a (lateral) surface of the cuboid-shaped waveguide on which an output waveguide is arranged and/or an (imaginary) 2-dimensional plane defined/indicated or extending by/through a (lateral) surface of the cuboid-shaped waveguide on which an output waveguide is arranged. The angle α describes the smallest angle enclosed by these two surfaces and/or (imaginary) planes.
Figure 2 shows the same arrangement 100 as figure 1 but from a two-dimensional top view. The geometric center of the input waveguide 10 is positioned, seen from this two-dimensional top-view of the arrangement, over the geometric center of the cuboid-shaped waveguide 20 (or over the geometric center of the surface of the cuboid-shaped waveguide 20 on which the input waveguide 10 is coupled to).
The output waveguides 22, 24, 26, 28 are coupled to lateral surfaces of the cuboid-shaped waveguide 20. As show in figure 2, the angle α is - identically - to be defined as an angle enclosed by the polarization direction a wave travelling/propagating through the input waveguide 10 and a lateral surface of the cuboid-shaped waveguide 20 and as an angle enclosed by an inner surface of the cuboid-shaped input waveguide 10 and a lateral surface of the cuboid-shaped waveguide 20.
A ratio of the power/magnitude of the electromagnetic energy provided at the Ports and/or the output waveguides 22, 24, 26, 28 relative to the power/magnitude of the electromagnetic energy provided into the input waveguide is defined by the angle o. In particular, the output waveguides 22, 26 (0° Port 1 and 0° Port 2) each provide 0.5 cos (a) of the electromagnetic power/magnitude provided into the input waveguide 10, wherein the output waveguides 24, 28 (90° Port 1 and 90° Port 2) each provide 0.5 sin (α) of the electromagnetic power/magnitude provided into the input waveguide 10.
Since the input waveguide 10 may be implemented as an element rotable with respect to the cuboid-shaped waveguide 20, the angle α may be adjusted as required. In consequence, also a ratio of the output power/magnitude provided at certain Ports may be adjusted as required.
Figure 3 illustrates that the power/magnitude provided at a certain Port and/or an waveguide depends on the angle α shown in figures 1 and 2. In an extreme case (a = 90°) the power/magnitude provided at two Ports or output waveguides can be reduced to substantially zero. On the other hand, the remaining Ports may provide a power, which, in addition, substantially equals the power provided into the input waveguide. Of course, this effect can be switched/changed/adjusted by rotating the input waveguide about 90°.
Figures 4 and 5 show another waveguide arrangement 200 comprising a cylindrical-shaped input waveguide 30, wherein the remaining elements correspond to the arrangement 100 shown in figures 1 and 2.
Since the cylindrical-shaped input waveguide 30 does not force or steady a certain polarization direction provided into the input waveguide 30, the angle α is defined exclusively by the polarization direction of the electromagnetic wave provided and a lateral surface of the cuboid waveguide 20. However, by adjusting the polarization direction of the provided electromagnetic wave by means other than a rotation of the input waveguide 30 an effect similar to the one described above is to be achieved. In other words, changing the polarization direction of an electromagnetic wave provided into the cylindrical-shaped input waveguide 30 directly affects the power/magnitude of the waves provided by the output waveguide 22, 24, 26, 28 and/or the Ports. This effect can be achieved without implementing any movable parts, which enhances the reliability and compactness of the shown waveguide arrangement.
Figure 6 shows further examples for cross-sectional geometries for input waveguides and/or output waveguides. In particular, the input waveguide and/or output waveguides may comprise - at least partially - rectangular-, quadratic-, rhombus, spherical- and/or elliptical shaped cross-sectional geometries. Further, other implementations of the waveguide arrangement may include waveguides comprising other geometries than shown and/or described.
Figure 7 shows an alternative waveguide arrangement 300 comprising a cylindrical-shaped waveguide 40 coupled to a plurality of output waveguides, particularly four output waveguides 22, 24, 26, 28, each defining a Port to provide electromagnetic wave energy. A cuboid-shaped input 10 waveguide is rotatably coupled to a top-surface of the cylindrical-shaped waveguide.
Analogue to the waveguide arrangement 100 shown in figure 1 and figure 2, a direction of the polarization of the electromagnetic wave travelling/propagating through the input waveguide 10 can be determined/changed by rotating the input waveguide 10. In consequence, also a ratio of/between the magnitude/power of the electromagnetic waves travelling/propagating through the four output waveguides 22, 24, 26, 28 can be determined/influenced/changed by rotating the cuboid input waveguide 10.
Conclusively, it is emphasized that the subject-matter shown in the figures does not limit the subject-matter claimed and does merely serve to enhance the understanding of the disclosure. However, the features shown in the figures and described above are included in the disclosure and can explicitly be combined with further features of the disclosure.

Claims

A waveguide arrangement (100, 200) comprising:
a cuboid-shaped waveguide (20) coupled to a plurality of output waveguides (22, 24, 26, 28); and

a cuboid-shaped input waveguide (10) coupled to the cuboid-shaped waveguide (20), wherein a propagation direction of an electromagnetic wave guided through the cuboid-shaped input waveguide (10) is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides (22, 24, 26, 28); wherein

the waveguide arrangement is configured to split an electromagnetic wave provided into the cuboid-shaped input waveguide (10) into a plurality of electromagnetic waves guided through the output waveguides (22, 24, 26, 28), wherein

a power ratio of the plurality of electromagnetic waves travelling through the output waveguides (22, 24, 26, 28) is defined by an angle, a, enclosed by a polarization of the wave guided by the cuboid-shaped input waveguide (10) and a side surface of the cuboid-shaped waveguide (20) on which any one of the output waveguides is arranged,

characterized in that

the cuboid-shaped input waveguide (10) is rotatably coupled to the cuboid-shaped waveguide (20) such that a power ratio between the electromagnetic waves provided or guided by the output waveguides (22, 24, 26, 28) is adjustable.
The waveguide arrangement (100, 200) according to claim 1, comprising
two or four or more than four output waveguides (22, 24, 26, 28).
The waveguide arrangement (100, 200) according any one of the preceding claims, wherein
at least two output waveguides of the plurality of output waveguides (22, 24, 26, 28) are arranged at surfaces of the cuboid-shaped waveguide (20), which oppose each other, and/or

each of the output waveguides of the plurality of output waveguides (22, 24, 26, 28) opposes another of the output waveguides coupled with the cuboid-shaped waveguide (20).
The waveguide arrangement (100, 200) according any one of the preceding claims, wherein
one or two or four or all of the output waveguides are cuboid shaped (22, 24, 26, 28) or cylindrical-shaped output waveguides.
The waveguide arrangement (100, 200) according any one of the preceding claims, wherein
two or four or all of the output waveguides (22, 24, 26, 28) are identically shaped.
The waveguide arrangement (100) according any one of the preceding claims, wherein
the polarization direction of the electromagnetic wave travelling through the cuboid-shaped input waveguide (10) is determined by a shape of the cuboid-shaped input waveguide, and/or

the polarization direction of the electromagnetic wave travelling through the cuboid-shaped input waveguide (10) is perpendicular and/or parallel to a side surface of the cuboid-shaped input waveguide (10).
The waveguide arrangement (100, 200) according any one of the preceding claims, wherein
the waveguide arrangement comprises four output waveguides (22, 24, 26, 28) each coupled to the cuboid-shaped waveguide (20), wherein

each of the four output waveguides (22, 24, 26, 28) opposes another of the output waveguides coupled to the cuboid-shaped waveguide,

wherein a power of an electromagnetic wave travelling in one of the output waveguide is

0.5 cos (a) or 0.5 sin (a) of the power of the electromagnetic wave provided into the cuboid-shaped input waveguide (10).
A waveguide arrangement (300) comprising:
a cylindrical-shaped waveguide (40) coupled to a plurality of output waveguides (22, 24, 26, 28); and

a cuboid-shaped input waveguide (10) coupled to the cylindrical-shaped waveguide (40), wherein a propagation direction of an electromagnetic wave guided through the cuboid-shaped input waveguide (10) is perpendicular to propagation directions of electromagnetic waves, which are guided through the output waveguides (22, 24, 26, 28); wherein

the waveguide arrangement is configured to split an electromagnetic wave provided into the cuboid-shaped input waveguide (10) into a plurality of electromagnetic waves guided through the output waveguides (22, 24, 26, 28), wherein

a power ratio of the plurality of electromagnetic waves travelling through the output waveguides (22, 24, 26, 28) is defined by a polarization direction of the wave guided by the cuboid-shaped input waveguide (10), and wherein

the polarization direction of the electromagnetic wave travelling through the input waveguide (10) is determined by a shape of the cuboid-shaped input (10) waveguide

and wherein the cuboid-shaped input waveguide (10) is rotatably coupled to the cylindrical-shaped waveguide (40) such that a power ratio between the electromagnetic waves provided or guided by the output waveguides (22, 24, 26, 28) is adjustable.
The waveguide arrangement (300) according to claim 8, wherein
the waveguide arrangement comprises four output waveguides (22, 24, 26, 28), and/or

each of the output waveguides of the plurality of output waveguides (22, 24, 26, 28) opposes another of the output waveguides coupled with the cylindrical-shaped waveguide (40).